A Study of Lean Construction Practices in Gaza Strip
A Study of Lean Construction Practices in Gaza Strip
A Study of Lean Construction Practices in Gaza Strip
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The Islamic University <strong>of</strong> <strong>Gaza</strong><br />
Deanery <strong>of</strong> Higher Studies<br />
Faculty <strong>of</strong> Eng<strong>in</strong>eer<strong>in</strong>g<br />
Civil Eng<strong>in</strong>eer<strong>in</strong>g Department<br />
<strong>Construction</strong> Management<br />
A <strong>Study</strong> <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong><br />
<strong>Practices</strong> <strong>in</strong> <strong>Gaza</strong> <strong>Strip</strong><br />
ةﺰﻏ عﺎﻄﻗ ﻲﻓ<br />
ﺲﻠﺴﻟا ءﺎﻨﺒﻟا<br />
ﻖﻴﺒﻄﺗ<br />
Ramdane M. El-Kourd<br />
Supervised by<br />
Dr. Salah R. Agha<br />
Dr. Mamoun A. Alqedra<br />
ةﺰﻏ - ﺔﻴﻣﻼﺳﻹا ﺔﻌﻣﺎﺠﻟا<br />
ﺎﻴﻠﻌﻟا تﺎﺳارﺪﻟا ةدﺎﻤﻋ<br />
ﺔﺳﺪﻨﻬﻟا ﺔﻴﻠآ<br />
ﺔﻴﻧﺪﻤﻟا ﺔﺳﺪﻨﻬﻟا ﻢﺴﻗ<br />
ﻊﻳرﺎﺸﻤﻟا ةرادإ<br />
ﺔﺳارد<br />
A Thesis Submitted <strong>in</strong> Partial Fulfillment <strong>of</strong> the Requirements for the<br />
Degree <strong>of</strong> Master <strong>of</strong> Science <strong>in</strong> <strong>Construction</strong> Management<br />
July, 2009
Dedication<br />
I would like to dedicate this work to my family for<br />
their sacrifice and endless support<br />
Ramdane Mohammed El-Kourd<br />
I
Acknowledgment<br />
I would like to express my deepest appreciation to my<br />
supervisors Dr. Salah R. Agha and Dr. Mamoun A.<br />
Alqedra for their pr<strong>of</strong>essional guidance, useful advice,<br />
cont<strong>in</strong>uous encouragement, and support that made this<br />
thesis possible.<br />
Deepest thanks go for the staff <strong>of</strong> construction<br />
management at the Islamic University for their<br />
academic and scientific supervision dur<strong>in</strong>g my study at<br />
the Islamic University.<br />
Gratitude is due to Abu-Shahla consultant <strong>of</strong>fice for<br />
their help <strong>in</strong> provid<strong>in</strong>g the required documents.<br />
II
III
ABSTRACT<br />
This research deals with the problem <strong>of</strong> waste <strong>in</strong> time, materials, resources and<br />
achievement <strong>of</strong> customer needs. This study has been applied to a contract<strong>in</strong>g company<br />
<strong>in</strong> the construction <strong>of</strong> a project located <strong>in</strong> GAZA. The ma<strong>in</strong> objective <strong>of</strong> this study is to<br />
apply the pr<strong>in</strong>ciples <strong>of</strong> lean to the construction <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong>. The mechanism <strong>of</strong><br />
research implementation consists <strong>of</strong> two stages:<br />
Stage one: Theoretical study <strong>of</strong> various Arabic and English references and Master<br />
researches from the Islamic University, studies that deal with the waste and the problem<br />
<strong>of</strong> contractors’ performance. The criteria that have been derived can be applied to<br />
construction projects <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong>.<br />
Stage two: The methodology <strong>of</strong> apply<strong>in</strong>g lean construction was represented <strong>in</strong> 10<br />
po<strong>in</strong>ts, the standardization tools and the five why tools as described <strong>in</strong> the current study<br />
<strong>in</strong> order to achieve the lean construction <strong>in</strong> reduc<strong>in</strong>g the activity and steps, thus<br />
m<strong>in</strong>imiz<strong>in</strong>g the duration by the elim<strong>in</strong>ation <strong>of</strong> the non-value added process <strong>in</strong> the<br />
activity by us<strong>in</strong>g arena simulation.<br />
The study <strong>of</strong> the project has been implemented <strong>in</strong> the <strong>Gaza</strong> strip because <strong>of</strong> the lack <strong>of</strong><br />
projects under construction due to the situation <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong>. The data <strong>of</strong> the<br />
project was taken from the daily reports. These reports showed the duration and steps <strong>of</strong><br />
the process for execut<strong>in</strong>g the project. Measur<strong>in</strong>g the value and the non-value added <strong>in</strong><br />
the process that used standardization tools and showed the cause <strong>of</strong> waste by us<strong>in</strong>g the<br />
five why tools. Consequently, def<strong>in</strong><strong>in</strong>g solution to deal with them.<br />
Us<strong>in</strong>g simulation was to measure the effect <strong>of</strong> non-value added on each process <strong>in</strong> the<br />
project.<br />
Results showed that us<strong>in</strong>g lean construction reduced the number <strong>of</strong> steps <strong>in</strong> the whole<br />
project by 57%. The non-value added decreased from 81% to 14% <strong>in</strong> the duration <strong>of</strong> the<br />
project. The total cycle time <strong>of</strong> the project was reduced by 75%.<br />
<strong>Lean</strong> construction is new <strong>in</strong> the field <strong>of</strong> construction <strong>in</strong> the world <strong>in</strong> general and <strong>in</strong> the<br />
Arab countries <strong>in</strong> particular.<br />
After prov<strong>in</strong>g the potential <strong>of</strong> apply<strong>in</strong>g lean, the focus should be on obstacles <strong>of</strong> lean<br />
implementation.<br />
IV
Table <strong>of</strong> Contents<br />
Dedication.........................................................................................................................I<br />
Acknowledgment.............................................................................................................II<br />
Arabic Abstract............................................................................................................. III<br />
Abstract.......................................................................................................................... IV<br />
Table <strong>of</strong> Contents........................................................................................................... V<br />
List <strong>of</strong> Abbreviations ................................................................................................. VIII<br />
List <strong>of</strong> Tables ................................................................................................................. IX<br />
List <strong>of</strong> Figures............................................................................................................... .XI<br />
Chapter One: Introduction<br />
1. 1 Statement <strong>of</strong> the problem............................................................................ 2<br />
1. 2 Research aim and objectives....................................................................... 2<br />
1.3 Methodology outl<strong>in</strong>e................................................................................... 2<br />
1.4 Thesis contents............................................................................................ 2<br />
Chapter Two: <strong>Lean</strong> <strong>Construction</strong><br />
2.1 The history <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong> ................................................................... 4<br />
2.2 <strong>Lean</strong> <strong>Construction</strong> Def<strong>in</strong>ition ......................................................................... 5<br />
2.3 Impact <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong> .......................................................................... 6<br />
2.4 <strong>Lean</strong> <strong>Construction</strong> Pr<strong>in</strong>ciples...........................................................................6<br />
2.4.1 Value ........................................................... 6<br />
2.4.2 Value Stream ........................................................... 6<br />
2.4.3 Flow ........................................................... 7<br />
2.4.4 Pull ........................................................... 7<br />
2.4.5 Perfection ........................................................... 7<br />
2.5 Criteria <strong>of</strong> <strong>Lean</strong> construction ......................................................................... 9<br />
2.5.1 Non Value-Added Activities Reduction.......................................... 9<br />
2.5.2 Increase Output Value ................................................................... 9<br />
2.5.3 Variability Reduction....................................................................... 9<br />
2.5.4 Cycle Time Reduction ................................................................... 10<br />
2.5.5 Simplify by M<strong>in</strong>imiz<strong>in</strong>g the Number <strong>of</strong> Steps............................... 11<br />
V
2.5.6 Increase Output Flexibility ............................................................ 12<br />
2.5.7 Increase Process Transparency ...................................................... 12<br />
2.5.8 Focus Control on the Complete Process........................................ 13<br />
2.5.9 Build Cont<strong>in</strong>uous Improvement <strong>in</strong>to the Process .......................... 13<br />
2.5.10 Balance Flow Improvement with Conversion Improvement....... 14<br />
2.5.11 Benchmark................................................................................... 14<br />
2.6. Tools <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong><br />
2.6.1 Just <strong>in</strong> Time (JIT).......................................................................... 15<br />
2.6.2 Last Planner System....................................................................... 16<br />
2.6.3. Increased Visualization................................................................. 18<br />
2.6.4. First Run Studies........................................................................... 19<br />
2.6.5. Daily Huddle Meet<strong>in</strong>gs................................................................. 19<br />
2.6.6. The 5s Process .............................................................................. 20<br />
2.6.7. Fail-Safe for Quality ..................................................................... 21<br />
2.6.8 Productivity Standardization.......................................................... 21<br />
2.6.9 The Five Why's ............................................................................... 22<br />
2.7 <strong>Construction</strong> Waste..................................................................................... 22<br />
2.8 <strong>Construction</strong> Waste <strong>in</strong> <strong>Gaza</strong> <strong>Strip</strong>............................................................... 25<br />
2.9 Summary ..................................................................................................... 29<br />
Chapter Three: Methodology<br />
3.1 Research Strategy ........................................................................................ 31<br />
3.2 Data Collection ............................................................................................. 31<br />
3.3 Application <strong>of</strong> <strong>Lean</strong> Pr<strong>in</strong>ciples <strong>in</strong> <strong>Construction</strong> ........................................... 33<br />
Chapter four: Application<br />
4.1 Project Description ....................................................................................... 35<br />
4.2 Project Activities........................................................................................... 36<br />
4.3 <strong>Lean</strong> criteria Procedure................................................................................. 36<br />
4. 4 Non Value Added Process Identification..................................................... 41<br />
4 .4.1 Mobilization and Excavation Activity............................................. 42<br />
4.4.2 Pla<strong>in</strong> Concrete................................................................................... 42<br />
4.4.3 Foundation Activity.......................................................................... 43<br />
4.4.4 Neck Column Activity...................................................................... 44<br />
VI
4.4.5 Isolation ............................................................................................ 45<br />
4.4.6 Backfill<strong>in</strong>g ........................................................................................ 45<br />
4.4.7 Ground Beam ................................................................................... 46<br />
4.4. 8 Ground Floor Column ..................................................................... 46<br />
4.4. 9 Ground Floor ................................................................................... 47<br />
4.4.10 Ground Floor Slab ......................................................................... 48<br />
4.4.11 First Floor Columns........................................................................ 48<br />
4.4.12 First Floor Slab ............................................................................... 49<br />
4.4.13 Ground Floor Build<strong>in</strong>g.................................................................... 50<br />
4.4.14 First Floor Build<strong>in</strong>g ........................................................................ 51<br />
4.5 Remove or Reduce the Influence <strong>of</strong> Waste .................................................. 52<br />
4.5.1 Mobilization and Excavation Activity................................................. 59<br />
4.5.2 Pla<strong>in</strong> Concrete...................................................................................... 59<br />
4.5.3 Foundation ........................................................................................... 60<br />
4.5.4 Neck Column ....................................................................................... 60<br />
4.5.5 Isolation ............................................................................................... 61<br />
4.5.6 Backfill<strong>in</strong>g ........................................................................................... 61<br />
4.5.7 Ground Beam....................................................................................... 62<br />
4.5.8 Column Ground Floor.......................................................................... 62<br />
4.5.9 Ground Floor........................................................................................ 63<br />
4.5.10 Ground Floor Slab ............................................................................. 63<br />
4.5.11 Column First Floor............................................................................. 64<br />
4.5.12 First Floor Slab .................................................................................. 64<br />
4.5.13 Build<strong>in</strong>g <strong>in</strong> Ground Floor .................................................................. 65<br />
4.5.14 Build<strong>in</strong>g <strong>in</strong> First Floor ....................................................................... 66<br />
4.6 Identify the Cause <strong>of</strong> Wastes ........................................................................ 66<br />
4.7 F<strong>in</strong>d<strong>in</strong>g the Largest Non-Value Added Activity........................................... 69<br />
4.7 Application <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong> for Future <strong>Construction</strong> Project ............. 79<br />
Chapter Five: Conclusions and Recommendations<br />
5.1 Conclusions................................................................................................... 82<br />
5.2 Recommendations…..................................................................................... 83<br />
References...................................................................................................................... 84<br />
VII
Appendices<br />
Appendix (A): Daily Report<br />
Appendix (B): Arena Simulation<br />
Appendix ( C): Simulation result <strong>of</strong> the project before apply<strong>in</strong>g eight po<strong>in</strong>ts and after<br />
apply<strong>in</strong>g lean tools<br />
Appendix (D): Simulation Result after apply<strong>in</strong>g "0" for three biggest non-value added<br />
processes <strong>of</strong> the project dur<strong>in</strong>g apply<strong>in</strong>g eight po<strong>in</strong>ts<br />
VIII
F. Floor First Floor<br />
G. Floor Ground Floor<br />
List <strong>of</strong> Abbreviations<br />
IGLC International Group <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong><br />
JIT Just <strong>in</strong> Time<br />
LC <strong>Lean</strong> <strong>Construction</strong><br />
LPS Last Planner System<br />
NUMMI New United Motor Manufactur<strong>in</strong>g Inc.<br />
NVA Non Value Added<br />
PMI Project Management Institute<br />
PPC Percent Plan Complete<br />
RPS Reverse Phase Schedul<strong>in</strong>g<br />
PS Pilot <strong>Study</strong><br />
SN Steps Number<br />
SWLA Six-Week Look Ahead<br />
TMS Toyota Manufactur<strong>in</strong>g System<br />
VA Value Added<br />
VAS Value Added Steps<br />
VSM Value Stream Mapp<strong>in</strong>g<br />
IX
List <strong>of</strong> Tables<br />
Table 2.1: Conceptualization <strong>of</strong> lean pr<strong>in</strong>ciple <strong>in</strong> construction........................................ 8<br />
Table 2.2: 5S Purpose and Goals.................................................................................... 20<br />
Table 3.1: Productivity <strong>of</strong> resources <strong>in</strong> <strong>Gaza</strong> <strong>Strip</strong>……………………………………..32<br />
Table 4.1: Details <strong>of</strong> project .......................................................................................... 35<br />
Table 4.2: Productivity <strong>of</strong> the Project activities ............................................................. 38<br />
Table4.3: NVA and VA activities <strong>in</strong> mobilization and excavation ................................ 42<br />
Table 4.4: NVA and VA processes <strong>in</strong> pla<strong>in</strong> concrete ................................................... 42<br />
Table 4.5: NVA and VA processes <strong>in</strong> foundation ........................................................ 43<br />
Table 4.6: NVA and VA processes <strong>in</strong> neck column ....................................................... 44<br />
Table 4.7: NVA and VA processes <strong>in</strong> isolation.............................................................. 45<br />
Table 4.8: NVA and VA processes <strong>in</strong> Back fill<strong>in</strong>g......................................................... 45<br />
Table 4.9: NVA and VA processes for ground beam activity........................................ 46<br />
Table 4.10: NVA and VA processes for G.Floor column .............................................. 46<br />
Table 4.11: NVA and VA processes for ground floor.................................................... 47<br />
Table 4.12: NVA and VA processes <strong>in</strong> slab for Ground Floor....................................... 48<br />
Table 4.13: NVA and VA processes <strong>in</strong> column for F.Floor........................................... 49<br />
Table 4.14: NVA and VA processes <strong>in</strong> slab for first Floor ............................................ 49<br />
Table 4.15: NVA and VA processes <strong>in</strong> build<strong>in</strong>g for G.Floor......................................... 50<br />
Table 4.16: NVA and VA processes <strong>in</strong> build<strong>in</strong>g for F.Floor.......................................... 51<br />
Table 4.17: Simulation result.......................................................................................... 56<br />
Table 4.18: Waste elim<strong>in</strong>ation <strong>in</strong> mobilization and excavation...................................... 59<br />
Table 4.19: Waste elim<strong>in</strong>ation <strong>in</strong> pla<strong>in</strong> concrete ............................................................ 59<br />
Table 4.20: Waste elim<strong>in</strong>ation <strong>in</strong> Foundation................................................................. 60<br />
Table 4.21: Waste elim<strong>in</strong>ation <strong>in</strong> column neck .............................................................. 60<br />
Table 4.22: Waste elim<strong>in</strong>ation <strong>in</strong> isolation ..................................................................... 61<br />
Table 4.23: Waste elim<strong>in</strong>ation for backfill<strong>in</strong>g............................................................... .61<br />
Table 4.24: Waste elim<strong>in</strong>ation <strong>in</strong> ground beam.............................................................. 62<br />
Table 4.25: Waste elim<strong>in</strong>ation for ground floor column .............................................. .62<br />
Table 4.26: Waste elim<strong>in</strong>ation for ground floor ............................................................ .63<br />
Table 4.27: Waste elim<strong>in</strong>ation for G.Floor slab ............................................................ 63<br />
X
Table 4.28: Waste elim<strong>in</strong>ation for F.Floor column ....................................................... 64<br />
Table 4.29: Waste elim<strong>in</strong>ation for F.Floor Slab ............................................................. 64<br />
Table 4.30: Waste elim<strong>in</strong>ation processes for build<strong>in</strong>g for G.Floor ................................ 65<br />
Table 4.31: Waste elim<strong>in</strong>ation <strong>in</strong> build<strong>in</strong>g for F.Floor................................................... 65<br />
Table 4.31: Difference between activity before and after apply<strong>in</strong>g lean........................ 66<br />
Table 4.33: Total project duration ................................................................................ 70<br />
Table 4.34: Activities <strong>in</strong> a descend<strong>in</strong>g order based on duration..................................... 71<br />
Table 4.35: Greatest duration <strong>of</strong> waste <strong>in</strong> activity.......................................................... 72<br />
Table 4.36: Project duration without the most wast<strong>in</strong>g activity .................................... .72<br />
Table 4.37: Balanc<strong>in</strong>g the process .................................................................................. 74<br />
Table 4.38: Cycle time compared................................................................................... 78<br />
Table 4.39: Process assigned and process completed..................................................... 80<br />
XI
List <strong>of</strong> Figures<br />
Figure 2.1: Reduction <strong>of</strong> cycle time................................................................................ 11<br />
Figure 2.2: Last Planner plann<strong>in</strong>g................................................................................... 18<br />
Figure 2.3: Seven wastes ................................................................................................ 24<br />
Figure 4.1: Procedure <strong>of</strong> the application <strong>of</strong> lean pr<strong>in</strong>ciples ................................ …..… 37<br />
Figure 4.2: Application <strong>of</strong> lean to mobilization and excavation..................................... 52<br />
Figure 4.3: Excavation process data ............................................................................... 53<br />
Figure 4.4: Laboratory process data ............................................................................... 53<br />
Figure 4.5: Application <strong>of</strong> lean to pla<strong>in</strong> concrete ........................................................... 54<br />
Figure 4.6: Formwork process data ................................................................................ 54<br />
Figure 4.7: Cast<strong>in</strong>g pla<strong>in</strong> concrete process data ............................................................. 55<br />
Figure 4.8: Remove form work process data.................................................................. 55<br />
Figure 4.9: Compar<strong>in</strong>g value added steps to value added time ...................................... 68<br />
Figure 4.10: Cause <strong>of</strong> failure .......................................................................................... 69<br />
Figure 4.11:Simulation model ........................................................................................ 69<br />
Figure 4.12: Duration variability before <strong>in</strong>troduc<strong>in</strong>g buffer........................................... 73<br />
Figure 4.13: Duration variability after <strong>in</strong>troduc<strong>in</strong>g buffer.............................................. 78<br />
Figure 4.14: Actual PPC <strong>of</strong> each week........................................................................... 80<br />
Figure 4.15: Average PPC <strong>of</strong> each four week ................................................................ 81<br />
XII
Chapter One<br />
Introduction<br />
<strong>Lean</strong> production was orig<strong>in</strong>ally encapsulated with<strong>in</strong> the Toyota Manufactur<strong>in</strong>g System<br />
and is well articulated by Womack (1990). <strong>Lean</strong> th<strong>in</strong>k<strong>in</strong>g subsequently became the<br />
generic term to describe universal application beyond manufactur<strong>in</strong>g (Womack and<br />
Jones, 1996). The ideas <strong>of</strong> lean th<strong>in</strong>k<strong>in</strong>g comprise a complex amalgam <strong>of</strong> ideas<br />
<strong>in</strong>clud<strong>in</strong>g cont<strong>in</strong>uous improvement, flattened organization structures, teamwork, the<br />
elim<strong>in</strong>ation <strong>of</strong> waste, efficient use <strong>of</strong> resources and co-operative supply cha<strong>in</strong><br />
management. With<strong>in</strong> the UK construction <strong>in</strong>dustry, the language <strong>of</strong> lean th<strong>in</strong>k<strong>in</strong>g has<br />
become synonymous with the best practice. Confidence <strong>in</strong> these ideas rema<strong>in</strong>s so high<br />
that the lean construction is an established component <strong>of</strong> construction best practice<br />
(Green et al., 2005).<br />
<strong>Lean</strong> construction much like current practice has the goal <strong>of</strong> better meet<strong>in</strong>g customer<br />
needs while us<strong>in</strong>g less <strong>of</strong> everyth<strong>in</strong>g. But unlike current practice, lean construction rests<br />
on production management pr<strong>in</strong>ciples. The result is a new project delivery system that<br />
can be applied to any k<strong>in</strong>d <strong>of</strong> construction but it is particularly suited for complex,<br />
uncerta<strong>in</strong>, and quick projects (Gregory et al., 1999).<br />
Projects <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong> are characterized by: low productivity, errors, poor coord<strong>in</strong>ation,<br />
bad reputation, high accident rates, <strong>in</strong>sufficient quality and overruns <strong>in</strong> cost<br />
and schedule…etc.(Yahia, 2004).<br />
The study was applied to a construction company, with wide experience <strong>in</strong> the field <strong>of</strong><br />
construction <strong>in</strong> <strong>Gaza</strong> <strong>Strip</strong>. The craftsmen with more than 10 years experience were met<br />
so as to compare their productivity with that <strong>of</strong> those work<strong>in</strong>g at the Center National <strong>of</strong><br />
Animation Enterprises and Treatment <strong>of</strong> Information for Labor <strong>in</strong> Algeria. The reason<br />
<strong>of</strong> lack <strong>of</strong> percent plan complete <strong>of</strong> work <strong>in</strong> the process, which means the rate <strong>of</strong> the<br />
processes that were applied compared with that which should be applied, was def<strong>in</strong>ed<br />
from the eng<strong>in</strong>eer <strong>in</strong> Abu Shahla <strong>of</strong>fice by us<strong>in</strong>g the five why tools <strong>of</strong> lean construction.<br />
F<strong>in</strong>ally, the result <strong>of</strong> apply<strong>in</strong>g lean construction, its methodology, and tools were<br />
<strong>of</strong>fered.<br />
1
1.1 Statement <strong>of</strong> the Problem<br />
Most <strong>of</strong> the construction projects <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong> are characterized by <strong>in</strong>efficiencies,<br />
large variability and low performance and thus wast<strong>in</strong>g time, money and other resources<br />
(Said, 2006). In this thesis, we will show the expected benefits <strong>of</strong> us<strong>in</strong>g some lean tools<br />
<strong>in</strong> <strong>Gaza</strong> construction <strong>in</strong>dustry <strong>in</strong> order to reduce or elim<strong>in</strong>ate waste and eventually<br />
satisfy customer needs.<br />
1. 2 Research Aim and Objectives<br />
The aim <strong>of</strong> this research is to study the status quo <strong>of</strong> the application <strong>of</strong> lean construction<br />
practices <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong> and their implications on the performance. The aim <strong>of</strong> this<br />
research can be divided <strong>in</strong>to the follow<strong>in</strong>g objectives:<br />
1. To identify the criteria <strong>of</strong> lean as they apply to construction projects.<br />
2. To identify basic lean tools for process improvement.<br />
3. To identify methodology for application lean tools<br />
4. To <strong>in</strong>vestigate the impact <strong>of</strong> lean practices.<br />
1.3 Methodology Outl<strong>in</strong>e<br />
The methodology used <strong>in</strong> undertak<strong>in</strong>g the study has consisted <strong>of</strong> three stages:<br />
1. Literature review <strong>in</strong>clud<strong>in</strong>g lean pr<strong>in</strong>ciples, lean tools and criteria <strong>of</strong> lean<br />
construction.<br />
2. A project was selected. Then, the processes and activities <strong>of</strong> the project were<br />
analyzed us<strong>in</strong>g the daily reports. The duration and steps were found out.<br />
3. Standardization and five why tools were applied on the project so as to reduce<br />
the non value added process. Simulation was used to measure the impact <strong>of</strong><br />
value added.<br />
F<strong>in</strong>ally, results and recommendations are given.<br />
1.4 Thesis contents<br />
This thesis <strong>in</strong>cludes five chapters. Chapter One <strong>in</strong>troduces the problem statement,<br />
objectives and methodology outl<strong>in</strong>e. Chapter Two <strong>in</strong>troduces literature review <strong>in</strong>clud<strong>in</strong>g<br />
the history <strong>of</strong> lean construction, lean construction pr<strong>in</strong>ciples, lean construction criteria,<br />
lean construction tools, and seven wastes. In chapter three, methodology is given <strong>in</strong><br />
2
details. Chapter Four analyzes case study data before and after apply<strong>in</strong>g lean tools.<br />
F<strong>in</strong>ally, conclusions and recommendations are given <strong>in</strong> Chapter Five.<br />
3
2.1 <strong>Lean</strong> <strong>Construction</strong> History<br />
Chapter Two<br />
<strong>Lean</strong> <strong>Construction</strong><br />
The lean construction system <strong>in</strong>itially appeared after the Second World War as<br />
“Toyota system” or “lean manufactur<strong>in</strong>g system”. Japan was defeated <strong>in</strong> the war, which<br />
caused a lack <strong>of</strong> f<strong>in</strong>ancial, physical and human resources thus result<strong>in</strong>g <strong>in</strong> the<br />
superiority <strong>of</strong> American companies for the auto <strong>in</strong>dustry over Japanese companies by a<br />
factor <strong>of</strong> 10 cars <strong>in</strong> production.<br />
Then, Toyota leaders (Ohno and others), thought about the creation <strong>of</strong> this system<br />
“Toyota system”.<br />
Taiichi Ohno, who was given the task <strong>of</strong> develop<strong>in</strong>g a system that would<br />
enhance productivity at Toyota, is generally considered to be the primary force beh<strong>in</strong>d<br />
his system. Ohno chose some ideas from the west and particularly from Henry Ford’s<br />
book “Today and tomorrow.” Ford’s mov<strong>in</strong>g assembly l<strong>in</strong>e <strong>of</strong> cont<strong>in</strong>uously flow<strong>in</strong>g<br />
material formed the basis for the Toyota production system. After some<br />
experimentation, the Toyota production system was developed and was called “Just <strong>in</strong><br />
Time” between 1945 and 1970. Then the name was changed <strong>in</strong>to “ <strong>Lean</strong> Production” as<br />
the previous name seemed unsuitable. The system is still grow<strong>in</strong>g today all over the<br />
world. The basic underly<strong>in</strong>g idea <strong>of</strong> this system is to m<strong>in</strong>imize the non value added.<br />
In order to compete <strong>in</strong> today’s fiercely competitive market, US manufacturers<br />
have come to realize that the traditional mass production concept has to be adapted to<br />
the new ideas <strong>of</strong> lean manufactur<strong>in</strong>g. A study that was done at the Massachusetts<br />
Institute <strong>of</strong> Technology <strong>of</strong> the movement from mass production to world lean<br />
manufactur<strong>in</strong>g. The study underscored the great success <strong>of</strong> Toyota at NUMMI (New<br />
United Motor Manufactur<strong>in</strong>g Inc.) and brought out the huge gap that existed between<br />
the Japanese and the western automotive <strong>in</strong>dustry. The ideas came to be adopted <strong>in</strong> the<br />
US because the Japanese companies developed, produced and distributed products with<br />
half or less human effort, capital <strong>in</strong>vestment, floor space, tools, materials, time, and<br />
overall the expense (Abudallah et al., 2003).<br />
4
The lean movement <strong>in</strong> construction started around 1992 with the creation <strong>of</strong> the<br />
International Group <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong>, which accepted the Ohno’s production<br />
system design criteria as a standard <strong>of</strong> perfection. S<strong>in</strong>ce then, and especially over the<br />
past decade, organizations all over the world have been look<strong>in</strong>g for ways to <strong>in</strong>crease<br />
competitive advantage for the delivery <strong>of</strong> capital projects through the application <strong>of</strong> lean<br />
concepts and techniques (Arbulu et al., 2006).<br />
Today, there are an Arabic <strong>in</strong>cl<strong>in</strong>ation towards the application <strong>of</strong> lean system <strong>in</strong><br />
the local projects where we f<strong>in</strong>d it <strong>in</strong> many productive projects: military cloth<strong>in</strong>g<br />
<strong>in</strong>dustry as <strong>in</strong> Iraq which got a big success and a big production development. A lot<br />
researches, masters and doctoral theses recommended to apply it at the <strong>Construction</strong><br />
projects level <strong>in</strong> the Arabic countries (Sameh, 2008).<br />
2.2 <strong>Lean</strong> <strong>Construction</strong> Def<strong>in</strong>ition<br />
<strong>Lean</strong> construction presents a coherent synthesis <strong>of</strong> the most effective techniques for<br />
elim<strong>in</strong>at<strong>in</strong>g waste and deliver<strong>in</strong>g significant susta<strong>in</strong>ed improvement. <strong>in</strong> cost, time,<br />
quality and safety simultaneously. In fact, lean construction has many def<strong>in</strong>itions:<br />
Ballard (2004) def<strong>in</strong>es lean "added value by elim<strong>in</strong>at<strong>in</strong>g waste, be<strong>in</strong>g responsive to<br />
change, focus<strong>in</strong>g on quality, and enhanc<strong>in</strong>g the effectiveness <strong>of</strong> the workforce.<br />
Typically, 95% <strong>of</strong> all lead time is non–value added". Ballard and Howell (2004) def<strong>in</strong>ed<br />
it as “a temporary production system while deliver<strong>in</strong>g the product with maximum value<br />
and m<strong>in</strong>imum waste". whereas the lean construction <strong>in</strong>stitute (2003) def<strong>in</strong>es lean<br />
construction as, “a production management based approach to project delivery. <strong>Lean</strong><br />
production management has caused a revolution <strong>in</strong> manufactur<strong>in</strong>g design, supply and<br />
assembly. But Reiser (2000) def<strong>in</strong>es lean construction as, "a project delivery system<br />
based on the lean production management process, orig<strong>in</strong>ally developed by the Toyota<br />
Motor Company that is aimed at improv<strong>in</strong>g value by satisfy<strong>in</strong>g customer needs and<br />
improv<strong>in</strong>g performance".<br />
F<strong>in</strong>ally, lean construction can be def<strong>in</strong>ed as added value by elim<strong>in</strong>at<strong>in</strong>g the waste <strong>of</strong><br />
space floor, material and the productivity <strong>of</strong> resources.<br />
5
2.3 Impact <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong><br />
Accord<strong>in</strong>g to (Colarelli <strong>Construction</strong>, 2005; Arbulu et al., 2006; Reiser et al., 2000),<br />
lean construction provides key benefits and its impacts are as follows:<br />
1. It delivers more value to the client with less waste <strong>of</strong> time and resources.<br />
2. It helps contractors improve processes and overall project delivery.<br />
3. It improves productivity by improv<strong>in</strong>g plann<strong>in</strong>g.<br />
4. It helps accommodat<strong>in</strong>g change.<br />
5. It reduces cost, accelerates delivery, and improves both quality and safety.<br />
6. It delivers products or services on time and with<strong>in</strong> budget.<br />
7. It <strong>in</strong>jects reliability, accountability, certa<strong>in</strong>ty, and honesty <strong>in</strong>to the project<br />
environment.<br />
8. It reduces system noise.<br />
9. It promotes cont<strong>in</strong>uous improvement <strong>in</strong> project delivery methods through<br />
lessons learned.<br />
2.4 <strong>Lean</strong> <strong>Construction</strong> Pr<strong>in</strong>ciples<br />
<strong>Lean</strong> construction consists <strong>of</strong> the follow<strong>in</strong>g five pr<strong>in</strong>ciples:<br />
2.4.1 Value<br />
The first and most critical lean pr<strong>in</strong>ciple as presented <strong>in</strong> lean th<strong>in</strong>k<strong>in</strong>g is value. Womack<br />
and Jones(2003) emphasize that value can only be def<strong>in</strong>ed by the ultimate customer<br />
and only mean<strong>in</strong>gful when it is expressed <strong>in</strong> terms <strong>of</strong> a specific product (a good, or a<br />
service, and <strong>of</strong>ten both at once) which meets the customer’s needs at a specific price<br />
and specific time.<br />
2.4.2 Value Stream<br />
The second lean pr<strong>in</strong>ciple as presented <strong>in</strong> lean th<strong>in</strong>k<strong>in</strong>g is value stream, Womack and<br />
Jones(2003) emphasize that value stream can only be def<strong>in</strong>ed by specific activities<br />
required to design, order and provide a specific product from concept to launch, order to<br />
delivery, raw material <strong>in</strong>to the hands <strong>of</strong> the customer.<br />
6
2.4.3 Flow<br />
The third pr<strong>in</strong>ciple is flow, once all the wasteful activities are elim<strong>in</strong>ated, the rema<strong>in</strong><strong>in</strong>g<br />
value-added steps need to ‘flow’. Conceptually companies have a difficult time<br />
apply<strong>in</strong>g beyond <strong>in</strong>ternal departments. True <strong>in</strong>tegration <strong>of</strong> functions and departments <strong>in</strong><br />
a company <strong>in</strong>to product teams organized along the value stream enables and promotes<br />
flow <strong>of</strong> <strong>in</strong>formation and materials. Thus construction process is composed <strong>of</strong> two<br />
different types <strong>of</strong> flows:<br />
- Material process consist<strong>in</strong>g <strong>of</strong> the flows <strong>of</strong> material to the site, <strong>in</strong>clud<strong>in</strong>g process<strong>in</strong>g<br />
and assembl<strong>in</strong>g on site.<br />
- Work processes <strong>of</strong> construction teams. The temporal and spatial flows <strong>of</strong> construction<br />
teams on site which are <strong>of</strong>ten closely associated with the material processes (koskela et<br />
al., 1992).<br />
2.4.4 Pull<br />
The fourth lean pr<strong>in</strong>ciple as presented <strong>in</strong> lean th<strong>in</strong>k<strong>in</strong>g is pull, Womack and Jones(2003)<br />
emphasize that pull can only be def<strong>in</strong>ed by imply<strong>in</strong>g the ability to design and make<br />
exactly what the customer wants just when they want it. Noth<strong>in</strong>g should be made until it<br />
is needed, then it should be made quickly.<br />
2.4.5 Perfection<br />
The fifth lean pr<strong>in</strong>ciple as presented <strong>in</strong> lean th<strong>in</strong>k<strong>in</strong>g is perfection. Womack and Jones<br />
(2003) emphasize that pull can only be def<strong>in</strong>ed by perfection imply<strong>in</strong>g the complete<br />
elim<strong>in</strong>ation <strong>of</strong> waste. Important th<strong>in</strong>gs to envision is the type <strong>of</strong> product and operat<strong>in</strong>g<br />
technologies needed to improve.<br />
The conceptualization <strong>of</strong> the lean <strong>in</strong> construction as developed by Björnfot (2006) is<br />
shown <strong>in</strong> Table (2.1).<br />
7
Table 2.1 Conceptualization <strong>of</strong> lean pr<strong>in</strong>ciple <strong>in</strong> construction (Björnfot, 2006).<br />
No <strong>Lean</strong> pr<strong>in</strong>ciple Conceptualization <strong>in</strong> construction<br />
1 Value<br />
2 Value stream<br />
3 Flow<br />
4 Pull<br />
5 Perfection<br />
a) Def<strong>in</strong>e the customer.<br />
b) Def<strong>in</strong>e what is value to the customer.<br />
c) Def<strong>in</strong>e what is value to the delivery team.<br />
d) Def<strong>in</strong>e how value is specified by products.<br />
a) Def<strong>in</strong>e all and activities required for construction<br />
b. Def<strong>in</strong>e all resources required for construction.<br />
c) Standardize current practice.<br />
d) Def<strong>in</strong>e and locate key component suppliers.<br />
a) Identify none-value added activities (waste).<br />
b) Remove or reduce the <strong>in</strong>fluence <strong>of</strong> waste as it is observed<br />
c) Identify key performance <strong>in</strong>dicators.<br />
d) Measure performance.<br />
a) Keep the production system flexible to customer<br />
requirements.<br />
b) Keep the production system adaptable to future customer<br />
requirements.<br />
c) Exercise a conscious effort at shorten<strong>in</strong>g lead and cycle<br />
times.<br />
d) Perform work at the last responsible moment.<br />
a) Keep the production system transparent for all <strong>in</strong>volved<br />
stakeholders.<br />
b) Capture and implement experience from completed<br />
projects.<br />
c) Exercise a conscious effort at improv<strong>in</strong>g value for<br />
customers.<br />
d) Exercise a conscious effort at improv<strong>in</strong>g the execution <strong>of</strong><br />
work.<br />
8
2.5 Criteria <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong><br />
Koskela (1992) applied lean production <strong>in</strong> the construction with eleven criteria which<br />
are shown bellow:<br />
2.5.1 Non-value added activities reduction<br />
Reduc<strong>in</strong>g the share <strong>of</strong> non value-added activities is a fundamental guidel<strong>in</strong>e. Experience<br />
shows that non value-added activities dom<strong>in</strong>ate most processes; usually only 3% to 20<br />
% <strong>of</strong> steps add value (Ciampa et al., 1991), and their share <strong>of</strong> the total cycle time is<br />
negligible, from 0.5 to 5 % (Stalk and Hout et al.,1990).<br />
There are three ma<strong>in</strong> causes for the presence <strong>of</strong> non value-added activities:<br />
• <strong>Construction</strong> Management: Non value-added activities are existed by<br />
traditional management. Every time a task is subdivided <strong>in</strong>to two subtasks<br />
executed by different specialists, This leads to an expansion <strong>of</strong> the non valueadded<br />
activities(such as : <strong>in</strong>spect<strong>in</strong>g, wait<strong>in</strong>g …etc) .<br />
• Ignorance: Especially, it exists <strong>in</strong> the adm<strong>in</strong>istration <strong>of</strong> construction. The<br />
volume <strong>of</strong> non value-added activities is not measured. This requires contact<strong>in</strong>g<br />
with a project manager with a wide experience <strong>in</strong> deal<strong>in</strong>g with the use <strong>of</strong> lean<br />
tools.<br />
• Seven wastes dur<strong>in</strong>g construction: There are mistakes <strong>in</strong> the field or defects <strong>in</strong><br />
material.<br />
2.5.2 Increase output value through systematic consideration <strong>of</strong> customer<br />
This is considered the second criteria. S<strong>in</strong>ce value added is achieved accord<strong>in</strong>g to<br />
customer’s requirements without any exaggeration. F<strong>in</strong>d<strong>in</strong>g, for example the enterprise<br />
companies are clients to the consultant. The consultant eng<strong>in</strong>eer’s <strong>of</strong>fice has to give the<br />
design without any errors, the quantity <strong>of</strong> bidd<strong>in</strong>g cope with the design, the duration <strong>of</strong><br />
project is sensible. Consider<strong>in</strong>g the owner is a contractor’s customer, who aims to get a<br />
build<strong>in</strong>g complied with specification <strong>of</strong> bidd<strong>in</strong>g, time schedule and costs as <strong>in</strong> the<br />
contract.<br />
2.5.3 Variability reduction<br />
This is considered the third criteria. Schonberg (1986) says that “the reduc<strong>in</strong>g <strong>of</strong><br />
variation must be considered an essential aim”. So, hav<strong>in</strong>g to measure the reasons <strong>of</strong> the<br />
variation and work on reduc<strong>in</strong>g it, can be done by standardization. It works to measure<br />
the rate <strong>of</strong> standardization <strong>of</strong> work per hour or day. So this can make master schedule<br />
9
for measur<strong>in</strong>g the percent plan complete (PPC) and look for the causes <strong>of</strong> failure. In<br />
addition, PPC also helps to reduce the variation.<br />
2.5.4 Cycle time reduction<br />
The cycle time is the time required for execut<strong>in</strong>g the process traverse the construction<br />
flow. The cycle time is used to measure the flow processes and it is a more useful than<br />
cost and quality. It can be represented as follows:<br />
Cycle time = Process<strong>in</strong>g time + <strong>in</strong>spection time + wait time + move time<br />
The new construction philosophy aims to compress the cycle time, which forces the<br />
reduction <strong>of</strong> <strong>in</strong>spection, move and wait time.<br />
In addition to the forced elim<strong>in</strong>ation <strong>of</strong> wastes, compression <strong>of</strong> the total cycle time gives<br />
the follow<strong>in</strong>g benefits: faster delivery to the customer, reduced need to make forecasts<br />
about future demands, decrease <strong>of</strong> disruption <strong>of</strong> the construction process due to change<br />
orders, easier management because there are fewer customer orders to keep track <strong>of</strong>.<br />
The pr<strong>in</strong>ciple <strong>of</strong> cycle time compression also has other <strong>in</strong>terest<strong>in</strong>g implications:<br />
1. From the perspective <strong>of</strong> control, it is important that the cycles <strong>of</strong> deviation detection<br />
and correction be speedy.<br />
2. In design and plann<strong>in</strong>g, there are many open-ended tasks that benefit from an<br />
iterative search for successively better (if not optimal) solutions. The shorter the<br />
cycle time, the more cycles are affordable.<br />
3. From the po<strong>in</strong>t <strong>of</strong> view <strong>of</strong> improvement, every layer <strong>in</strong> an organizational hierarchy<br />
adds to the cycle time <strong>of</strong> error correction and problem solv<strong>in</strong>g. This simple fact<br />
provides the new construction philosophy’s motivation to decrease organizational<br />
layers, thereby empower<strong>in</strong>g the persons work<strong>in</strong>g directly with<strong>in</strong> the flow.<br />
Practical approaches to cycle time reduction <strong>in</strong>clude the follow<strong>in</strong>g: Elim<strong>in</strong>at<strong>in</strong>g work<strong>in</strong>-progress<br />
(this orig<strong>in</strong>al JIT goal reduces the wait<strong>in</strong>g time and thus the cycle time),<br />
reduc<strong>in</strong>g stor<strong>in</strong>g time and sett<strong>in</strong>g temporary stores so that mov<strong>in</strong>g distances are<br />
m<strong>in</strong>imized, thus keep<strong>in</strong>g th<strong>in</strong>gs mov<strong>in</strong>g; smooth<strong>in</strong>g and synchroniz<strong>in</strong>g the flows,<br />
reduc<strong>in</strong>g variability, chang<strong>in</strong>g activities from sequential order to parallel order, and<br />
eventually isolat<strong>in</strong>g the ma<strong>in</strong> value-added sequence from support work. In general,<br />
solv<strong>in</strong>g the control problems and constra<strong>in</strong>ts prevents a speedy flow.<br />
10
Figure (2.1) shows that the cycle time can be progressively compressed through<br />
elim<strong>in</strong>ation <strong>of</strong> non value added activities and variability reduction.<br />
Waste<br />
time<br />
Process<strong>in</strong>g<br />
time<br />
Waste<br />
time<br />
Process<strong>in</strong>g<br />
time<br />
Waste<br />
time<br />
Process<strong>in</strong>g<br />
time<br />
Process<strong>in</strong>g<br />
time<br />
Figure 2.1 Reduction <strong>of</strong> cycle time (Berl<strong>in</strong>er and Brimson, 1988 )<br />
2.5.5 Simplify by m<strong>in</strong>imiz<strong>in</strong>g the number <strong>of</strong> steps and parts<br />
The human ability to deal with complexity is restricted. This complexity <strong>of</strong> a product<br />
<strong>in</strong>creases non value-added activities. Complexity means the <strong>in</strong>crease <strong>of</strong> the number <strong>of</strong><br />
steps <strong>in</strong> the production process. Reduc<strong>in</strong>g the number <strong>of</strong> steps leads to a reduction <strong>of</strong><br />
cost and an <strong>in</strong>crease <strong>in</strong> reliability <strong>in</strong> the production process. Simplification can be<br />
understood as, reduc<strong>in</strong>g <strong>of</strong> the number <strong>of</strong> components <strong>in</strong> a product, and reduc<strong>in</strong>g <strong>of</strong> the<br />
number <strong>of</strong> steps <strong>in</strong> a material or <strong>in</strong>formation flow. Simplification can be realized, on the<br />
one hand, by elim<strong>in</strong>at<strong>in</strong>g non value-added activities from the production process, and on<br />
the other hand by reconfigur<strong>in</strong>g value-added parts or steps. Organizational changes can<br />
also br<strong>in</strong>g about simplification. Vertical and horizontal division <strong>of</strong> labor always br<strong>in</strong>gs<br />
about non value-added activities, which can be elim<strong>in</strong>ated through self conta<strong>in</strong>ed units<br />
(multi-skilled, autonomous teams). Practical approaches to simplification <strong>in</strong>clude:<br />
shorten<strong>in</strong>g the flows by consolidat<strong>in</strong>g activities, reduc<strong>in</strong>g the part count <strong>of</strong> products<br />
through design changes or prefabricated parts, standardiz<strong>in</strong>g parts, materials, tools, etc.,<br />
decoupl<strong>in</strong>g l<strong>in</strong>kages, and m<strong>in</strong>imiz<strong>in</strong>g the amount <strong>of</strong> control <strong>in</strong>formation needed.<br />
11
2.5.6 Increase output flexibility<br />
Flexibility should be limited dur<strong>in</strong>g the period <strong>of</strong> construction. We can talk about it<br />
from the duration <strong>of</strong> the project, for example, by us<strong>in</strong>g standardization <strong>of</strong> works, we can<br />
add the number <strong>of</strong> resources to reduce the time, while the change <strong>in</strong> the activity affects<br />
the project.<br />
2.5.7 Increase process transparency<br />
In a theoretical sense, transparency means a separation <strong>of</strong> the network <strong>of</strong> <strong>in</strong>formation<br />
and the hierarchical structure <strong>of</strong> order giv<strong>in</strong>g, which <strong>in</strong> the classical organization theory<br />
are identical. The goal is thus to substitute self-control for formal control and related<br />
<strong>in</strong>formation gather<strong>in</strong>g.<br />
Transparency reduces errors and <strong>in</strong>creases motivation for improvement. Thus, it is an<br />
objective to make the production process transparent and observable for facilitation <strong>of</strong><br />
control and improvement: “to make the ma<strong>in</strong> flow <strong>of</strong> operations from start to f<strong>in</strong>ish<br />
visible and comprehensible to all employees” (Stalk and Hout 1989). This can be<br />
achieved by mak<strong>in</strong>g the process directly observable through organizational or physical<br />
means, measurements, and public display <strong>of</strong> <strong>in</strong>formation.<br />
Practical approaches for enhanced transparency <strong>in</strong>clude the follow<strong>in</strong>g:<br />
� Establish<strong>in</strong>g basic housekeep<strong>in</strong>g to elim<strong>in</strong>ate clutter.<br />
� Mak<strong>in</strong>g the process directly observable through appropriate layout and signage<br />
� Render<strong>in</strong>g <strong>in</strong>visible attributes <strong>of</strong> the process visible through measurements<br />
� Embody<strong>in</strong>g process <strong>in</strong>formation <strong>in</strong> work areas, tools, conta<strong>in</strong>ers, materials and<br />
<strong>in</strong>formation systems<br />
� Utiliz<strong>in</strong>g visual controls to enable any person to immediately recognize<br />
standards and deviations from them.<br />
� Reduc<strong>in</strong>g the <strong>in</strong>terdependence <strong>of</strong> production units (focused factories).<br />
2.5.8 Focus control on the complete process<br />
There are two causes <strong>of</strong> segmented flow control: the flow traverses different units <strong>in</strong> a<br />
hierarchical organization or crosses through an organizational border. In both cases,<br />
there is a risk <strong>of</strong> sub optimization.<br />
There are at least two prerequisites for focus<strong>in</strong>g control on complete processes. First,<br />
the complete process has to be measured. Secondly, there must a controll<strong>in</strong>g authority<br />
for the complete process. Several alternatives are currently used. In hierarchical<br />
12
organizations, process owners for cross-functional processes are appo<strong>in</strong>ted, with<br />
responsibility for the efficiency and effectiveness <strong>of</strong> that process (Rummler et al.,<br />
1990). A more radical solution is to let self-directed teams control their processes<br />
(Stewart et al., 1992).<br />
For <strong>in</strong>ter-organizational flows, long term co-operation with suppliers and team build<strong>in</strong>g<br />
has been <strong>in</strong>troduced with the goal <strong>of</strong> deriv<strong>in</strong>g mutual benefits from an optimized total<br />
flow.<br />
2.5.9 Build cont<strong>in</strong>uous improvement <strong>in</strong>to the process<br />
The effort to reduce waste and to <strong>in</strong>crease value is an <strong>in</strong>ternal, <strong>in</strong>cremental, and<br />
iterative activity that can and must be carried out cont<strong>in</strong>uously. There are several<br />
necessary methods for <strong>in</strong>stitutionaliz<strong>in</strong>g cont<strong>in</strong>uous improvement; these <strong>in</strong>clude the<br />
follow<strong>in</strong>g:<br />
� Measur<strong>in</strong>g and monitor<strong>in</strong>g improvement.<br />
� Sett<strong>in</strong>g stretch targets (e.g. for <strong>in</strong>ventory elim<strong>in</strong>ation or cycle time<br />
reduction), by means <strong>of</strong> which problems are unearthed and their solutions<br />
are stimulated.<br />
� Giv<strong>in</strong>g responsibility for improvement to all employees; a steady<br />
improvement from every organizational unit should be required and<br />
rewarded.<br />
� Us<strong>in</strong>g standard procedures as hypotheses <strong>of</strong> best practice, to be constantly<br />
challenged by better ways.<br />
� L<strong>in</strong>k<strong>in</strong>g improvement to control: improvement should be aimed at the<br />
current control constra<strong>in</strong>ts and problems <strong>of</strong> the process. The goal is to<br />
elim<strong>in</strong>ate the root <strong>of</strong> problems rather than to cope with their effects.<br />
2.5.10 Balance flow improvement with conversion improvement<br />
In the improvement <strong>of</strong> productive activities, both conversions and flows have to be<br />
addressed; however, the question is how these two alternatives should be balanced.<br />
For any production process, the flow and conversion aspects have a different<br />
potential for improvement. This goes as a rule:<br />
� The higher the complexity <strong>of</strong> the production process, the higher the impact<br />
<strong>of</strong> flow improvement<br />
13
� The more wastes <strong>in</strong>herent <strong>in</strong> the production process, the more pr<strong>of</strong>itable is<br />
flow improvement <strong>in</strong> comparison to conversion improvement.<br />
However, <strong>in</strong> a situation where flows have been neglected for decades, the potential<br />
for flow improvement is usually higher than conversion improvement. On the<br />
other hand, flow improvement can be started with smaller <strong>in</strong>vestments, but usually<br />
requires a longer time than a conversion improvement.<br />
The crucial issue is that flow improvement and conversion improvement are<br />
<strong>in</strong>timately <strong>in</strong>terconnected:<br />
� Better flows require less conversion capacity and thus less equipment<br />
<strong>in</strong>vestment<br />
� More controlled flows make implementation <strong>of</strong> new conversion technology<br />
easier<br />
� New conversion technology may provide smaller variability, and thus flow<br />
benefits.<br />
Therefore, one is tempted to agree with Ohno, who argues that “improvement<br />
adheres to a certa<strong>in</strong> order” (Ohno, 1988). It is <strong>of</strong>ten worthwhile to aggressively<br />
pursue flow process Improvement before major <strong>in</strong>vestments <strong>in</strong> new conversion<br />
technology: “Perfect exist<strong>in</strong>g processes to their full potential before design<strong>in</strong>g new<br />
ones” (Blaxill et al., 1991). Later, technology <strong>in</strong>vestments may be aimed at flow<br />
improvement or redesign.<br />
2.5.11 Benchmark<br />
Unlike technology for conversions, the best flow processes are not marketed to us; we<br />
have to f<strong>in</strong>d the world class processes ourselves.<br />
Often benchmark<strong>in</strong>g is a useful stimulus to achieve breakthrough improvement through<br />
radical reconfiguration <strong>of</strong> processes.<br />
The basic steps <strong>of</strong> benchmark<strong>in</strong>g <strong>in</strong>clude the follow<strong>in</strong>g (Camp et al., 1989)<br />
� Know<strong>in</strong>g the process; assess<strong>in</strong>g the strengths and weaknesses <strong>of</strong> sub<br />
processes.<br />
� Know<strong>in</strong>g the <strong>in</strong>dustry leaders or competitors; f<strong>in</strong>d<strong>in</strong>g, understand<strong>in</strong>g and<br />
compar<strong>in</strong>g the best practices.<br />
� Incorporat<strong>in</strong>g the best; copy<strong>in</strong>g, modify<strong>in</strong>g or <strong>in</strong>corporat<strong>in</strong>g the best<br />
practices <strong>in</strong> your own sub processes.<br />
14
� Ga<strong>in</strong><strong>in</strong>g superiority by comb<strong>in</strong><strong>in</strong>g exist<strong>in</strong>g strengths and the best external<br />
practices.<br />
2.6 Tools <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong><br />
The lean construction tools which can be applied on the construction projects are:<br />
2.6.1. Just <strong>in</strong> Time (JIT)<br />
It is a philosophy that works <strong>in</strong> the elim<strong>in</strong>ation <strong>of</strong> waste <strong>in</strong> all activities and operations.<br />
JIT system is a production cost system <strong>in</strong> the specified time for certa<strong>in</strong> productivity<br />
with<strong>in</strong> the project; productivity which leads to its development and reduce its costs.<br />
It is an <strong>in</strong>ventory costs system <strong>in</strong> a timely manner, which works on receiv<strong>in</strong>g materials<br />
today and use them tomorrow and this can be effected by adjust<strong>in</strong>g the time <strong>of</strong> material<br />
receipt at the time we start us<strong>in</strong>g it <strong>in</strong> production and adjust<strong>in</strong>g the time <strong>of</strong> completion<br />
with the time we delivered to customer. This represents a step <strong>in</strong> controll<strong>in</strong>g stocks<br />
systems lead<strong>in</strong>g to a JIT process.<br />
On this basis, the adjust<strong>in</strong>g time system which is work<strong>in</strong>g <strong>in</strong> production cost reduction<br />
is by reduc<strong>in</strong>g the supply periods.<br />
The most important JIT goals:<br />
• Dispens<strong>in</strong>g with all types <strong>of</strong> stock or reduced to a m<strong>in</strong>imum.<br />
• Reduc<strong>in</strong>g the wastage <strong>of</strong> time and resources <strong>in</strong> the productive processes.<br />
• Purchas<strong>in</strong>g <strong>in</strong> the appropriate time and quantities to meet consumer needs <strong>in</strong> a<br />
timely and quality Occasion.<br />
• The development <strong>of</strong> trust and relationship between the company and suppliers<br />
through the development <strong>of</strong> long-term goals that lead to confidence<br />
To deduce the problems and disadvantages <strong>of</strong> production costs at the time specified as<br />
follows:<br />
1. Difficulty <strong>of</strong> achiev<strong>in</strong>g some assumptions, such as the absence <strong>of</strong> defects <strong>in</strong><br />
production, as well as reach<strong>in</strong>g level units with zero. Fault, along with zero<br />
<strong>in</strong>ventory, means difficulty <strong>in</strong> achiev<strong>in</strong>g it <strong>in</strong> large-scale company or companies<br />
with seasonal activity.<br />
2. This system requires substantial cooperation among management, workers and<br />
suppliers, and we cannot apply this system without <strong>in</strong>tegration among those parties.<br />
15
3. System requires the need to develop general account<strong>in</strong>g systems, special cost<br />
system, and general costs concepts System.<br />
4. Some company do not accept the idea <strong>of</strong> the application <strong>of</strong> the system <strong>of</strong><br />
production costs <strong>in</strong> time because <strong>of</strong> its high cost, which occur at the beg<strong>in</strong>n<strong>in</strong>g <strong>of</strong> the<br />
application <strong>of</strong> this system by the preparation <strong>of</strong> adm<strong>in</strong>istrators and workers and by<br />
chang<strong>in</strong>g company deal<strong>in</strong>gs with both suppliers and customers.<br />
5. Adm<strong>in</strong>istrators are not conv<strong>in</strong>ced about the change from exist<strong>in</strong>g systems to a<br />
system <strong>of</strong> production costs <strong>in</strong> time because they fear its application failure.<br />
6. Closures is the biggest problem fac<strong>in</strong>g the economic side to provide materials as the<br />
stock <strong>in</strong> this system is equal to zero, and <strong>in</strong> the case <strong>of</strong> the closure, we will not f<strong>in</strong>d<br />
materials to be used by the contractor and consequently activities are halted.<br />
2.6.2 Last Planner System<br />
Ballard (2000) <strong>in</strong>dicates that Last Planner System (LPS) is a technique that shapes<br />
workflow and addresses project variability <strong>in</strong> construction. The Last Planner is the<br />
person or group accountable for operational plann<strong>in</strong>g, that is, the structur<strong>in</strong>g <strong>of</strong> product<br />
design to facilitate improved work flow, and production unit control, that is, the<br />
completion <strong>of</strong> <strong>in</strong>dividual assignments at the operational level. In the last planner system,<br />
the sequences <strong>of</strong> implementation (master schedule, Reverse Phase Schedules (RPS),<br />
six-week look ahead, Weekly Work Plan (WWP), Percent Plan Complete (PPC),<br />
constra<strong>in</strong>t analysis and variances analysis).<br />
The goals <strong>of</strong> last planner are to pull activities by reverse phase schedul<strong>in</strong>g through team<br />
plann<strong>in</strong>g and optimize resources <strong>in</strong> the long-term. This tool is similar to the Kanban<br />
system and production level<strong>in</strong>g tools <strong>in</strong> lean manufactur<strong>in</strong>g.<br />
2.6.2.1 Master Schedule<br />
The master schedule is an overall project schedule, with milestones, that is usually<br />
generated for use <strong>in</strong> the bid package. RPS is produced based on this master schedule.<br />
2.6.2.2 Reverse Phase Schedul<strong>in</strong>g (RPS)<br />
Ballard and Howell (2003) <strong>in</strong>dicated that a pull technique is used to develop a schedule<br />
that works backwards from the completion date by team plann<strong>in</strong>g; it is also called<br />
Reverse Phase Schedul<strong>in</strong>g (RPS). They also state that phase schedul<strong>in</strong>g is the l<strong>in</strong>k<br />
between work structur<strong>in</strong>g and production control, and the purpose <strong>of</strong> the phase schedule<br />
16
is to produce a plan for the <strong>in</strong>tegration and coord<strong>in</strong>ation <strong>of</strong> various specialists’<br />
operations.<br />
The reverse phase schedule is developed by a team consist<strong>in</strong>g <strong>of</strong> all the last planners. It<br />
is closer to reality than the prelim<strong>in</strong>ary optimal schedule which is the master schedule.<br />
However, without consider<strong>in</strong>g actual field factors <strong>in</strong> the RPS, the RPS is less accurate<br />
than the WWP.<br />
2.6.2.3 Six-Week Look Ahead (SWLA)<br />
Ballard (2000) <strong>in</strong>dicated that the tool for work flow control is look ahead schedules.<br />
SWLA shows what k<strong>in</strong>ds <strong>of</strong> work are supposed to be done <strong>in</strong> the future. In the look<br />
ahead w<strong>in</strong>dow, week 1 is next week, the week after the WWP meet<strong>in</strong>g. The number <strong>of</strong><br />
weeks <strong>of</strong> look ahead varies. For the design process, the look ahead w<strong>in</strong>dow could be 3<br />
to 12 weeks (Ballard 2000). All six-week-look ahead durations and schedules are<br />
estimated based on the results <strong>of</strong> the RPS, and constra<strong>in</strong>ts are <strong>in</strong>dicated <strong>in</strong> order to solve<br />
the problems before the actual production takes place. SWLA is distributed to all last<br />
planners at WWP meet<strong>in</strong>gs. <strong>Lean</strong> look ahead plann<strong>in</strong>g is the process to reduce<br />
uncerta<strong>in</strong>ty to achieve possible constra<strong>in</strong>t free assignments (Koskela et al., 2000).<br />
2.6.2.4 Weekly Work Plan (WWP)<br />
Should, Can, and Will are the key terms <strong>in</strong> WWP (Ballard 2000). Weekly Work Plan<br />
(WWP) is produced based on SWLA, the actual schedule, and the field condition before<br />
the weekly meet<strong>in</strong>g. Along with this plan, manpower from each trade will be adjusted to<br />
the need.<br />
• Should: Indicates the work that is required to be done accord<strong>in</strong>g to schedule<br />
requirements.<br />
• Can: Indicates the work which can actually be accomplished on account <strong>of</strong><br />
various constra<strong>in</strong>ts on the field.<br />
• Will: Reflects the work commitment which will be made after all the constra<strong>in</strong>ts<br />
are taken <strong>in</strong>to account.<br />
The WWP meet<strong>in</strong>g covers the weekly schedule, safety issues, quality issues, material<br />
needs, manpower, construction methods, backlog <strong>of</strong> ready work, and any problems that<br />
can occur <strong>in</strong> the field. It promotes two-way communication and team plann<strong>in</strong>g to share<br />
<strong>in</strong>formation on a project <strong>in</strong> an efficient and accurate way. It can improve safety, quality,<br />
17
the work flow, material flow, productivity, and the relationship among team members.<br />
Ballard and Howell (2003) <strong>in</strong>dicates that WWP should emphasize the learn<strong>in</strong>g process<br />
more by <strong>in</strong>vestigat<strong>in</strong>g the causes <strong>of</strong> delays on the WWP <strong>in</strong>stead <strong>of</strong> assign<strong>in</strong>g blames and<br />
only focus<strong>in</strong>g on PPC values. Variance analysis is conducted based on the work<br />
performance plan from the previous week. The causes <strong>of</strong> variance should be<br />
documented with<strong>in</strong> the WWP schedule (Figure 2.2)<br />
CAN<br />
SHOULD<br />
LAST PLANNER<br />
PLANNING<br />
Figure 2.2 Last Planner plann<strong>in</strong>g<br />
WILL<br />
2.6.2. 5 Percent Plan Complete (PPC)<br />
The measurement metric <strong>of</strong> Last Planner is the Percent Plan Complete (PPC) values. It<br />
is calculated as the number <strong>of</strong> activities that are completed as planned divided by the<br />
total number <strong>of</strong> planned activities (Ballard 2000). The positive (upward) slope between<br />
two PPC values means that production plann<strong>in</strong>g was reliable and vice versa. Accord<strong>in</strong>g<br />
to Ballard (1999), PPC values are highly variable and usually range from 30% to 70%<br />
without lean implementation. To achieve higher values (70% and above), additional<br />
lean construction tools such as first run studies have to be implemented.<br />
2.6.3 Increased Visualization<br />
The <strong>in</strong>creased visualization lean tool is about communicat<strong>in</strong>g key <strong>in</strong>formation<br />
effectively to the workforce through post<strong>in</strong>g various signs and labels around the<br />
construction site. Workers can remember elements such as workflow, performance<br />
targets, and specific required actions if they visualize them (Moser and Dos Santos<br />
2003). This <strong>in</strong>cludes signs related to safety, schedule, and quality. This tool is similar to<br />
18
the lean manufactur<strong>in</strong>g tool, Visual Controls, which is a cont<strong>in</strong>uous improvement<br />
activity that relates to the process control<br />
2.6.4 First Run Studies<br />
First Run Studies are used to redesign critical assignments (Ballard and Howell et al.,<br />
1977), part <strong>of</strong> cont<strong>in</strong>uous improvement effort; and <strong>in</strong>clude productivity studies and<br />
review work methods by redesign<strong>in</strong>g and streaml<strong>in</strong><strong>in</strong>g the different functions <strong>in</strong>volved.<br />
The studies commonly use video files, photos, or graphics to show the process or<br />
illustrate the work <strong>in</strong>struction. The first run <strong>of</strong> a selected craft operation should be<br />
exam<strong>in</strong>ed <strong>in</strong> detail, br<strong>in</strong>g<strong>in</strong>g ideas and suggestions to explore alternative ways <strong>of</strong> do<strong>in</strong>g<br />
the work. A PDCA cycle (plan, do, check, act) is suggested to develop the study: Plan<br />
refers to select work process to study, assemble people, analyze process steps,<br />
bra<strong>in</strong>storm how to elim<strong>in</strong>ate steps, check for safety, quality and productivity. Do means<br />
to try out ideas on the first run. Check is to describe and measure what actually happens.<br />
Act refers to reconven<strong>in</strong>g the team, and communicat<strong>in</strong>g the improved method and<br />
performance as the standard to meet.<br />
2.6.5 Daily Huddle Meet<strong>in</strong>gs (Tool-box Meet<strong>in</strong>gs)<br />
Two-way communication is the key <strong>of</strong> the daily huddle meet<strong>in</strong>g process <strong>in</strong> order to<br />
achieve employee <strong>in</strong>volvement. With awareness <strong>of</strong> the project and problem solv<strong>in</strong>g<br />
<strong>in</strong>volvement along with some tra<strong>in</strong><strong>in</strong>g that is provided by other tools, employee<br />
satisfaction (job mean<strong>in</strong>gfulness, self-esteem, sense <strong>of</strong> growth) will <strong>in</strong>crease. As part <strong>of</strong><br />
the improvement cycle, a brief daily start-up meet<strong>in</strong>g was conducted where team<br />
members quickly give the status <strong>of</strong> what they had been work<strong>in</strong>g on s<strong>in</strong>ce the previous<br />
day's meet<strong>in</strong>g, especially if an issue might prevent the completion <strong>of</strong> an assignment<br />
(Schwaber, 1995). This tool is similar to the lean manufactur<strong>in</strong>g concept <strong>of</strong> employee<br />
<strong>in</strong>volvement, which ensures rapid response to problems through empowerment <strong>of</strong><br />
workers, and cont<strong>in</strong>uous open communication through the tool box meet<strong>in</strong>gs.<br />
2.6.6 The 5s Process (Visual Work Place)<br />
• Sort<br />
The first level <strong>of</strong> housekeep<strong>in</strong>g consisted <strong>of</strong> separat<strong>in</strong>g material by reference and<br />
plac<strong>in</strong>g materials and tools close to the work areas with consideration <strong>of</strong> safety and<br />
crane movements.<br />
19
• Straighten<br />
Next, materials were piled <strong>in</strong> a regular pattern and tools were placed <strong>in</strong> gang boxes.<br />
Each subcontractor took responsibility for specific work areas on the job site.<br />
• Standardize<br />
The next level <strong>in</strong>cluded the preparation <strong>of</strong> a material layout design. The layout<br />
conta<strong>in</strong>ed key <strong>in</strong>formation <strong>of</strong> each work activity on the job site. The visual<br />
workplace helped locate <strong>in</strong>com<strong>in</strong>g material, reduce crane movements, and reduce<br />
walk<strong>in</strong>g distance for the crews.<br />
• Sh<strong>in</strong>e<br />
The next step consisted <strong>of</strong> keep<strong>in</strong>g a clean job site. Workers were encouraged to<br />
clean workplaces once an activity had been completed. A housekeep<strong>in</strong>g crew was<br />
set to check and clean hidden areas on the job site.<br />
• Susta<strong>in</strong><br />
The f<strong>in</strong>al level <strong>of</strong> housekeep<strong>in</strong>g sought to ma<strong>in</strong>ta<strong>in</strong> all previous practices throughout<br />
the project. At the end <strong>of</strong> the project, this level is not fully achieved, <strong>in</strong> part because<br />
project personnel did not view housekeep<strong>in</strong>g as a cont<strong>in</strong>uous effort. They had to be<br />
rem<strong>in</strong>ded frequently <strong>of</strong> housekeep<strong>in</strong>g practices.<br />
Table 2.2 resumes 5S purpose and goals.<br />
Table 2.2 5S Purpose and Goals<br />
5S Elements Purpose Goals<br />
Sort<br />
Set <strong>in</strong> Order<br />
Sh<strong>in</strong>e<br />
Elim<strong>in</strong>at<strong>in</strong>g what is not<br />
needed<br />
Creat<strong>in</strong>g the most<br />
effective physical layout<br />
possible<br />
Establish a clean<br />
environment<br />
20<br />
• Elim<strong>in</strong>ate unnecessary items.<br />
• Create means to keep them out <strong>of</strong> the<br />
environment.<br />
• Rega<strong>in</strong> valuable space.<br />
• Elim<strong>in</strong>ate safety hazards caused by<br />
clutter.<br />
• Produce more positive environment.<br />
• Design space that supports work<br />
flow.<br />
• Create a structure that supports<br />
neatness.<br />
• Organize tools, equipment, and<br />
materials <strong>in</strong> a way that facilitates<br />
efficient operations.<br />
• Remove clutter, debris from<br />
environment.<br />
• Identify problems through <strong>in</strong>spection<br />
and <strong>in</strong>itiate a correction process.
Table 2.2 5S Purpose and Goals (cont.)<br />
5S Elements Purpose Goals<br />
Standardization<br />
Susta<strong>in</strong><br />
2.6.7 Fail-Safe for Quality<br />
• Check for Quality<br />
Creat<strong>in</strong>g standard ways <strong>of</strong><br />
do<strong>in</strong>g/stor<strong>in</strong>g th<strong>in</strong>gs so<br />
anyone can di/f<strong>in</strong>d anyth<strong>in</strong>g.<br />
Integrat<strong>in</strong>g 5S pr<strong>in</strong>ciples <strong>in</strong>to<br />
the culture <strong>of</strong> the<br />
organization<br />
• Establish standards that describe how<br />
th<strong>in</strong>gs should exist.<br />
• Establish communication devices so<br />
that everyone may understand how<br />
th<strong>in</strong>gs work.<br />
• Form 5S habits.<br />
• Integrate 5S <strong>in</strong>to the organization's<br />
culture. become s the way th<strong>in</strong>gs are<br />
done around here.<br />
An overall quality assessment was completed at the beg<strong>in</strong>n<strong>in</strong>g <strong>of</strong> the project. Most<br />
quality issues could be addressed by standard practices, and it seemed there was<br />
little room for improvement. Dur<strong>in</strong>g the execution <strong>of</strong> the project, however, some<br />
critical items appeared such as a new vibration method for shear<strong>in</strong>g walls was<br />
suggested and implemented by the super<strong>in</strong>tendent <strong>of</strong> the project.<br />
• Check for Safety<br />
Safety was tracked with safety action plans, i.e., lists <strong>of</strong> ma<strong>in</strong> risk items prepared by<br />
each crew. Potential hazards were studied and explored dur<strong>in</strong>g the job. Most<br />
hazards, such as eye <strong>in</strong>juries, falls and trips, and hear<strong>in</strong>g loss, have standard<br />
countermeasures; however, <strong>in</strong> practice, workers have to be rem<strong>in</strong>ded <strong>of</strong> safety<br />
practices (Salem et al., 2006).<br />
2.6.8 Productivity Standardization<br />
Productivity is a measure <strong>of</strong> how much we produce per unit <strong>in</strong>put. From a client's<br />
perspective, higher productivity leads to lower costs, shorter construction programs,<br />
better value for money and a higher return on <strong>in</strong>vestment (Malcolm et al., 2001).<br />
Contractors’ pr<strong>of</strong>its from <strong>in</strong>creases <strong>in</strong> productivity are generally <strong>in</strong> the range <strong>of</strong> 2% to<br />
4% <strong>of</strong> turnover. The <strong>in</strong>crease <strong>in</strong> labor productivity by 25% would <strong>in</strong>crease their pr<strong>of</strong>it<br />
marg<strong>in</strong>s from 2% to 8%, or from 4 % to 10%, a two and a half to fourfold <strong>in</strong>crease <strong>in</strong><br />
pr<strong>of</strong>it.<br />
Partial Productivity = Total Output / (1) Input<br />
Labour Productivity =Total Output / Number <strong>of</strong> labor<br />
21
Material Productivity = Total Output / Amount <strong>of</strong> Material<br />
Mach<strong>in</strong>e Productivity = Value <strong>of</strong> production / Amount <strong>of</strong> work (Yahia, 2004).<br />
2.6.9 The Five Why's:<br />
Five whys as part <strong>of</strong> lean manufactur<strong>in</strong>g is a problem solv<strong>in</strong>g technique that allows you<br />
to get at the root cause <strong>of</strong> a problem fairly quickly. It was made popular as part <strong>of</strong> the<br />
Toyota Production System (1970’s.) Application <strong>of</strong> the strategy <strong>in</strong>volves tak<strong>in</strong>g any<br />
problem and ask<strong>in</strong>g “Why - what caused this problem”.<br />
The benefits <strong>of</strong> the 5 Whys are as follows:<br />
• It helps to quickly identify the root cause <strong>of</strong> a problem.<br />
• It helps determ<strong>in</strong>e the relationship between different root causes <strong>of</strong> a problem.<br />
• It can be learned quickly and does not require statistical analysis to be used.<br />
2.7 <strong>Construction</strong> Waste<br />
A number <strong>of</strong> def<strong>in</strong>itions <strong>of</strong> waste are available. In general, Alarcon (1994), Koskela<br />
(1992) and Love et al. (1997) argued that all those activities that produce costs, direct or<br />
<strong>in</strong>direct, and take time, resources or require storage but do not add value or progress to<br />
the product can be called waste. These waste categories are measured as a function <strong>of</strong><br />
their costs, <strong>in</strong>clud<strong>in</strong>g opportunity costs. Furthermore, other types <strong>of</strong> waste are related to<br />
the efficiency <strong>of</strong> process, equipment or personnel.<br />
Non value-added activity (also called waste): Activity that takes time, resources or<br />
space but does not add value.(koskela et al., 1992).<br />
Waste <strong>in</strong> the construction <strong>in</strong>dustry has been the subject <strong>of</strong> several research projects<br />
around the world <strong>in</strong> recent years (Formoso et al., 1999). The study by Skoyles (1987) <strong>in</strong><br />
the UK also suggested that all those <strong>in</strong>volved <strong>in</strong> the construction process contributed to<br />
waste. This <strong>in</strong>cludes those who design materials, plant and build<strong>in</strong>g; those who specify<br />
and communicate, for example, the quantity surveyors and head <strong>of</strong>fice staff; and<br />
particularly site managers and site operators.<br />
Therefore, the responsibility for m<strong>in</strong>imiz<strong>in</strong>g waste should be shared by all parties<br />
<strong>in</strong>volved <strong>in</strong> construction projects, <strong>in</strong>clud<strong>in</strong>g:<br />
• All managers <strong>in</strong> build<strong>in</strong>g organizations, not only site managers,<br />
• Those who design, manufacture and supply merchandise and plant used <strong>in</strong><br />
construction,<br />
22
• Those who design build<strong>in</strong>gs,<br />
• Those who specify, describe and account for the works, and<br />
• Those who provide briefs pay for and use build<strong>in</strong>gs.<br />
Graham and Smithers (1996) believed that construction waste could occur dur<strong>in</strong>g<br />
different project phases:<br />
• Design (plan errors, detail errors and design changes),<br />
• Procurement (shipp<strong>in</strong>g error and order<strong>in</strong>g error),<br />
• Materials handl<strong>in</strong>g (improper storage, deterioration and improper handl<strong>in</strong>g on and<br />
<strong>of</strong>f site)<br />
• Operation (human error, trades person, labors, equipment error, accidents and<br />
weather),<br />
• Residual (leftover and irreclaimable non-consumables), and<br />
• Other (theft, vandals and clients actions).<br />
Despite variations <strong>in</strong> construction projects, potential material waste is caused by similar<br />
<strong>in</strong>efficiencies <strong>in</strong> design, procurement, material handl<strong>in</strong>g, operation or residual on-site<br />
waste such as packag<strong>in</strong>g (Formoso et al., 1993 and Gavilan and Bernold, 1993).<br />
Research also <strong>in</strong>dicated that clients could be a source <strong>of</strong> waste through careless<br />
<strong>in</strong>spection procedures and variation orders dur<strong>in</strong>g the process. Initially, carelessness at<br />
the design stage can lead to excessive waste which creates a need to over order to avoid<br />
a shortage <strong>of</strong> materials on site (Graham and Smithers, 1996). Waste <strong>in</strong> construction is<br />
not only focused on the quantity <strong>of</strong> waste <strong>of</strong> materials on-site, but also related to several<br />
activities such as overproduction, wait<strong>in</strong>g time, material handl<strong>in</strong>g, process<strong>in</strong>g,<br />
<strong>in</strong>ventories and movement <strong>of</strong> workers (Formoso et al., 1999; Alarcon, 1994).<br />
Consolidat<strong>in</strong>g research from authors (Alarcon, 1995; Alwi, 1995; Koskela, 1993;<br />
Rob<strong>in</strong>son, 1991; Lee et al., 1999; Pheng and Hui, 1999), the ma<strong>in</strong> categories <strong>of</strong> waste<br />
dur<strong>in</strong>g the construction process can be described as: reworks/repairs, defects, material<br />
waste, delays, wait<strong>in</strong>g, poor material allocation, unnecessary material handl<strong>in</strong>g and<br />
material waste. In Chile, a research study from 1990 to 1994, focus<strong>in</strong>g on waste was<br />
conducted to identify the most relevant factors that produce waste <strong>of</strong> productive time <strong>in</strong><br />
build<strong>in</strong>g construction works (Serpell et al., 1995). The study concluded that wait<strong>in</strong>g<br />
time, idle time and travell<strong>in</strong>g time, <strong>in</strong>dicated as the ma<strong>in</strong> subcategory <strong>of</strong> noncontributory<br />
work (waste), expla<strong>in</strong>ed 87% <strong>of</strong> the total value <strong>of</strong> waste. Another<br />
23
<strong>in</strong>vestigation showed that 25 percent time sav<strong>in</strong>gs is achievable <strong>in</strong> a typical construction<br />
work package without <strong>in</strong>creas<strong>in</strong>g allocated resources (Mohamed et al., 1996).<br />
<strong>Lean</strong> construction maximizes value and reduces waste and applies specific techniques <strong>in</strong><br />
an <strong>in</strong>novative project delivery approach <strong>in</strong>clud<strong>in</strong>g supply cha<strong>in</strong> management and Just-<br />
In-Time techniques as well as the open shar<strong>in</strong>g <strong>of</strong> <strong>in</strong>formation between all the parties<br />
<strong>in</strong>volved <strong>in</strong> the production process. <strong>Lean</strong> manufactur<strong>in</strong>g is an outgrowth <strong>of</strong> the Toyota<br />
Production system that was developed by Taichii Ohno <strong>in</strong> Toyota <strong>in</strong> the 1950s. Ohno<br />
identified seven wastes <strong>in</strong> mass production systems (Figure 2.3).<br />
Wait<strong>in</strong>g time<br />
Defects<br />
Overprocess<strong>in</strong>g<br />
Overproduci<br />
ng<br />
The seven<br />
wastes<br />
Figure 2.3 Seven wastes<br />
24<br />
Motion<br />
Inventory<br />
Material<br />
Movement
2.8 <strong>Construction</strong> Waste <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong><br />
Accord<strong>in</strong>g to Said (2006), construction wastes <strong>Gaza</strong> <strong>Strip</strong> are classified accord<strong>in</strong>g to<br />
the seven wastes as follows:<br />
2.8.1 Over-production<br />
Over-production is unnecessarily produc<strong>in</strong>g more than demanded or produc<strong>in</strong>g it too<br />
early before it is needed. This <strong>in</strong>creases the risk <strong>of</strong> obsolescence, <strong>in</strong>creases the risk <strong>of</strong><br />
produc<strong>in</strong>g the wrong th<strong>in</strong>g and <strong>in</strong>creases the possibility <strong>of</strong> hav<strong>in</strong>g to sell those items at a<br />
discount or discard them as scrap. However, there are some cases when an extra supply<br />
<strong>of</strong> semi-f<strong>in</strong>ished or f<strong>in</strong>ished products is <strong>in</strong>tentionally ma<strong>in</strong>ta<strong>in</strong>ed, even by lean<br />
manufacturers.<br />
Over-production waste <strong>of</strong> construction <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong> is due to:<br />
1. Order<strong>in</strong>g <strong>of</strong> materials that do not fulfill project requirements def<strong>in</strong>ed on design<br />
documents, and wait<strong>in</strong>g for replacement.<br />
2. Over order<strong>in</strong>g or under order<strong>in</strong>g due to mistake <strong>in</strong> quantity surveys.<br />
3. Over order<strong>in</strong>g or under order<strong>in</strong>g due to lack <strong>of</strong> coord<strong>in</strong>ation between warehouse<br />
crews and construction crews.<br />
2.8.2 Defects: (Correction)<br />
In addition to physical defects which directly add to the costs <strong>of</strong> goods sold, this may<br />
<strong>in</strong>clude:<br />
errors <strong>in</strong> paperwork, provision <strong>of</strong> <strong>in</strong>correct <strong>in</strong>formation about the product, late delivery,<br />
production to <strong>in</strong>correct specifications, use <strong>of</strong> too much raw materials or generation <strong>of</strong><br />
unnecessary scrap, repair or rework wastes time and resources at every level <strong>of</strong> the<br />
organization, correction means do<strong>in</strong>g it twice which doubles an employee’s exposure to<br />
risk<br />
Defects waste <strong>of</strong> construction <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong> is due to :<br />
1. Damage materials on site.<br />
2. Unnecessary <strong>in</strong>ventories <strong>in</strong> site which lead to waste.<br />
3. Manufactur<strong>in</strong>g defects.<br />
4. Poor quality <strong>of</strong> materials.<br />
5. Use <strong>of</strong> <strong>in</strong>correct material, thus requir<strong>in</strong>g replacement.<br />
6. Equipment frequently breakdown.<br />
25
7. Poor technology <strong>of</strong> equipment.<br />
8. Shortage <strong>of</strong> tools and equipments required.<br />
10. Rework due to workers’ mistakes.<br />
11. Damage to work done caused by subsequent trades.<br />
12. Poor workmanship.<br />
2.8.3 Inventory<br />
Inventory waste means hav<strong>in</strong>g unnecessarily high levels <strong>of</strong> raw materials, work-<strong>in</strong>progress<br />
and f<strong>in</strong>ished products. Extra <strong>in</strong>ventory leads to higher <strong>in</strong>ventory f<strong>in</strong>anc<strong>in</strong>g<br />
costs, higher storage costs and higher defect rates.<br />
Inventory hides waste and defects as materials that have been fabricated and stored for<br />
various projects, backlog <strong>of</strong> good work over jobs, a batch <strong>of</strong> eng<strong>in</strong>eer<strong>in</strong>g<br />
recommendations, and massive amounts <strong>of</strong> data be<strong>in</strong>g stored for use at a later date or<br />
never used at all.<br />
Inventory waste <strong>of</strong> construction <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong> is due to:<br />
1. Wrong storage <strong>of</strong> materials.<br />
2. Inadequate stack<strong>in</strong>g and <strong>in</strong>sufficient storage on site.<br />
3. Insufficient <strong>in</strong>structions about storage and stack<strong>in</strong>g.<br />
4. Inappropriate storage lead<strong>in</strong>g to damage or deterioration.<br />
2.8.4 Transportation: (Material Movement)<br />
Transportation <strong>in</strong>cludes any movement <strong>of</strong> materials that does not add any value to the<br />
product, such as mov<strong>in</strong>g materials between workstations. The idea is that transportation<br />
<strong>of</strong> materials between productions stages should aim for the ideal that the output <strong>of</strong> one<br />
process is immediately used as the <strong>in</strong>put for the next process. Transportation between<br />
process<strong>in</strong>g stages results <strong>in</strong> prolong<strong>in</strong>g production cycle times, the <strong>in</strong>efficient use <strong>of</strong><br />
labor and space and can also be a source <strong>of</strong> m<strong>in</strong>or production stoppages. Unnecessarily<br />
mov<strong>in</strong>g materials wastes<br />
time, energy, resources, and <strong>in</strong>creases the likelihood <strong>of</strong> <strong>in</strong>jury such as mov<strong>in</strong>g work-<strong>in</strong>process<br />
from a site to site, mov<strong>in</strong>g an eng<strong>in</strong>eer<strong>in</strong>g recommendation from one area to<br />
another for review, mov<strong>in</strong>g pipe from location to location.<br />
Transportation waste <strong>of</strong> construction <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong> is due to:<br />
1. Damage dur<strong>in</strong>g transportation<br />
2. Use <strong>of</strong> <strong>in</strong>adequate tools and equipments<br />
26
3. Poor storage<br />
4. Far distance between place <strong>of</strong> work<strong>in</strong>g and storage.<br />
5. Unpacked supply (fragile).<br />
2.8.5 Wait<strong>in</strong>g<br />
Wait<strong>in</strong>g is idle time for workers or mach<strong>in</strong>es due to bottlenecks or <strong>in</strong>efficient<br />
production flow on the factory floor. Wait<strong>in</strong>g also <strong>in</strong>cludes small delays between<br />
process<strong>in</strong>g <strong>of</strong> units. Wait<strong>in</strong>g results <strong>in</strong> a significant cost <strong>in</strong>s<strong>of</strong>ar as it <strong>in</strong>creases labor<br />
costs and depreciation costs per unit <strong>of</strong> output are <strong>in</strong> general known as: wait<strong>in</strong>g for<br />
parts, wait<strong>in</strong>g for decisions or direction, wait<strong>in</strong>g for data or <strong>in</strong>formation, wait<strong>in</strong>g for<br />
recommendation and wait<strong>in</strong>g for supplies.<br />
Wait<strong>in</strong>g waste <strong>of</strong> construction <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong> is due to:<br />
1. Wait<strong>in</strong>g for design documents and draw<strong>in</strong>gs Motion.<br />
2. Rework that don't comply with draw<strong>in</strong>gs and specifications.<br />
3. Rework due to workers’ mistakes.<br />
4. Delays <strong>in</strong> pass<strong>in</strong>g <strong>of</strong> <strong>in</strong>formation to the contractor on products.<br />
5. Wait<strong>in</strong>g for workers or materials or equipments to arrive.<br />
6. Equipment frequently breakdown.<br />
7. Delay <strong>in</strong> commencement <strong>of</strong> project.<br />
8. Delay <strong>in</strong> perform<strong>in</strong>g <strong>in</strong>spection and test<strong>in</strong>g by the consultant eng<strong>in</strong>eer.<br />
9. Suspension <strong>of</strong> work by the owner.<br />
10. Change orders.<br />
2.8.6 Motion<br />
Motion <strong>in</strong>cludes any unnecessary physical motions or walk<strong>in</strong>g by workers which diverts<br />
them from actual process<strong>in</strong>g work. For example, this might <strong>in</strong>clude walk<strong>in</strong>g around the<br />
factory floor to look for a tool, or even unnecessary or difficult physical movements,<br />
due to poorly designed ergonomics, which slow down the workers. Unnecessary<br />
movement (walk<strong>in</strong>g, reach<strong>in</strong>g, lift<strong>in</strong>g, etc.) wastes time and energy such as walk<strong>in</strong>g<br />
back and forth between equipment and a truck to get tools or parts, walk<strong>in</strong>g back and<br />
forth between the draw<strong>in</strong>g table and a document storage area to get <strong>in</strong>formation, go<strong>in</strong>g<br />
to a warehouse to get parts<br />
Motion waste <strong>of</strong> construction <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong> is due to:<br />
1. Poor schedule to procurement the materials.<br />
27
2. Unnecessary material handl<strong>in</strong>g.<br />
3. Tradesmen slow/<strong>in</strong>effective.<br />
4. Far distance between place <strong>of</strong> work<strong>in</strong>g and storage.<br />
5. Poor distribution <strong>of</strong> materials <strong>in</strong> site.<br />
6. Lack <strong>of</strong> proper ma<strong>in</strong>ta<strong>in</strong>ed pathways.<br />
7. Difficulty <strong>in</strong> motion <strong>of</strong> worker <strong>in</strong> the site<br />
2.8.7 Over-process<strong>in</strong>g<br />
Over-process<strong>in</strong>g is un<strong>in</strong>tentionally do<strong>in</strong>g more process<strong>in</strong>g work than the customer<br />
requires <strong>in</strong> terms <strong>of</strong> product quality or features – such as polish<strong>in</strong>g or apply<strong>in</strong>g f<strong>in</strong>ish<strong>in</strong>g<br />
on some areas <strong>of</strong> a product that won’t be seen by the customer. Do<strong>in</strong>g more work tends<br />
to keep people “busy,” but adds no “value” such as writ<strong>in</strong>g a comprehensive legal<br />
agreement when a simple agreement would suffice, replac<strong>in</strong>g more parts than necessary,<br />
spend<strong>in</strong>g extra time do<strong>in</strong>g more analysis than is really necessary, unnecessary<br />
complexity.<br />
Over-process<strong>in</strong>g waste <strong>of</strong> construction <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong> is due to:<br />
1. Conversion waste from cutt<strong>in</strong>g uneconomical shapes.<br />
2. Us<strong>in</strong>g excessive quantities <strong>of</strong> materials more than the required.<br />
3. Wrong handl<strong>in</strong>g <strong>of</strong> materials.<br />
4. Insufficient <strong>in</strong>structions about handl<strong>in</strong>g.<br />
5. Lack <strong>of</strong> workers or tradesmen or subcontractors’ skill.<br />
6. Difficulty <strong>in</strong> performance and pr<strong>of</strong>essional work.<br />
7. Interaction between various specialists.<br />
8. Us<strong>in</strong>g untra<strong>in</strong>ed labors<br />
28
2.9 Summary<br />
The lean construction takes its idea from the lean manufactur<strong>in</strong>g by mak<strong>in</strong>g customer’s<br />
needs as the ma<strong>in</strong> priority <strong>of</strong> the company objectives. The application <strong>of</strong> lean<br />
construction started <strong>in</strong> 1992 by International Group <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong>. The ma<strong>in</strong><br />
objective <strong>of</strong> lean construction is to <strong>in</strong>crease the value added activities and remove or<br />
reduce the non-value added activities <strong>in</strong> the project. The impact <strong>of</strong> lean construction<br />
gives more value to the client with less waste <strong>of</strong> time and resources. It helps contractors<br />
improve processes and overall project delivery, improve productivity by improv<strong>in</strong>g the<br />
plann<strong>in</strong>g. The impact is also an approach well suited to accommodate change, reduces<br />
cost, accelerates delivery, improves both quality and safety, delivers products or<br />
services on time and with<strong>in</strong> budget. It also <strong>in</strong>jects reliability, accountability, certa<strong>in</strong>ty,<br />
and honesty <strong>in</strong>to the project environment and reduces system noise, improves project<br />
delivery methods and promotes cont<strong>in</strong>uous improvement <strong>in</strong> project delivery methods<br />
through lessons learned. <strong>Lean</strong> th<strong>in</strong>k<strong>in</strong>g consist <strong>of</strong> five po<strong>in</strong>ts: Value, value stream, flow,<br />
pull and perfection. Koskela (1992) applied lean production <strong>in</strong> the construction with<br />
eleven criteria which are: non-value-added activities reduction, <strong>in</strong>crease output value,<br />
variability reduction, cycle times reduction, simplifies by m<strong>in</strong>imiz<strong>in</strong>g the number <strong>of</strong><br />
steps, <strong>in</strong>crease output flexibility, <strong>in</strong>crease process transparency, benchmark, build<br />
cont<strong>in</strong>uous improvement <strong>in</strong>to the process, balance flow improvement with conversion<br />
improvement and focus control on the complete process. The lean construction tools<br />
are: Just <strong>in</strong> time (JIT), last planner system, <strong>in</strong>creased visualization, first run studies,<br />
productivity, the 5S process, fail-safe for quality, the 5 why's and daily huddle meet<strong>in</strong>gs.<br />
The seven wastes accord<strong>in</strong>g to the research thesis <strong>of</strong> the construction wastes <strong>in</strong> the<br />
<strong>Gaza</strong> <strong>Strip</strong> (Said, 2006) are: over-production (order<strong>in</strong>g <strong>of</strong> materials that do not fulfill<br />
project requirements def<strong>in</strong>ed on design documents, and wait<strong>in</strong>g for replacement, over<br />
order<strong>in</strong>g or under order<strong>in</strong>g due to a mistake <strong>in</strong> quantity surveys, over order<strong>in</strong>g or under<br />
order<strong>in</strong>g due to lack <strong>of</strong> coord<strong>in</strong>ation between warehouse and construction crews),<br />
defects (damage materials on site, unnecessary <strong>in</strong>ventories <strong>in</strong> site which lead to waste,<br />
poor quality <strong>of</strong> materials, use <strong>of</strong> <strong>in</strong>correct material, thus requir<strong>in</strong>g replacement,<br />
equipment frequently breakdown, poor technology <strong>of</strong> equipment, shortage <strong>of</strong> tools and<br />
equipments required, rework due to workers’ mistakes, damage to work done caused by<br />
subsequent trades, poor workmanship and choice <strong>of</strong> wrong construction method ),<br />
29
<strong>in</strong>ventory (Wrong storage <strong>of</strong> materials. Inadequate stack<strong>in</strong>g and <strong>in</strong>sufficient storage on<br />
site, <strong>in</strong>sufficient <strong>in</strong>structions about storage and stack<strong>in</strong>g and <strong>in</strong>appropriate storage<br />
lead<strong>in</strong>g to damage or deterioration), transportation (damage dur<strong>in</strong>g transportation, use<br />
<strong>of</strong> <strong>in</strong>adequate tools and equipments, poor storage, far distance between place <strong>of</strong> work<strong>in</strong>g<br />
and storage and unpacked supply), wait<strong>in</strong>g (wait<strong>in</strong>g for design documents and draw<strong>in</strong>gs<br />
motion, rework that does not comply with draw<strong>in</strong>gs and specifications, rework due to<br />
workers’ mistakes, delays <strong>in</strong> pass<strong>in</strong>g <strong>of</strong> <strong>in</strong>formation to the contractor on products,<br />
wait<strong>in</strong>g for workers or materials or equipments to arrive, equipment frequently<br />
breakdown, delay <strong>in</strong> commencement <strong>of</strong> project, delay <strong>in</strong> perform<strong>in</strong>g <strong>in</strong>spection and<br />
test<strong>in</strong>g by the consultant eng<strong>in</strong>eer and suspension <strong>of</strong> work by the owner and change<br />
orders ), motion (poor schedule to procurement the materials, unnecessary material<br />
handl<strong>in</strong>g, tradesmen slow/<strong>in</strong>effective, far distance between place <strong>of</strong> work<strong>in</strong>g and<br />
storage, poor distribution <strong>of</strong> materials <strong>in</strong> site, lack <strong>of</strong> proper ma<strong>in</strong>ta<strong>in</strong>ed pathways, and<br />
difficulty <strong>in</strong> motion <strong>of</strong> worker <strong>in</strong> the site ) and over-process<strong>in</strong>g (conversion waste from<br />
cutt<strong>in</strong>g uneconomical shapes, us<strong>in</strong>g excessive quantities <strong>of</strong> materials more than the<br />
required, wrong handl<strong>in</strong>g <strong>of</strong> materials, <strong>in</strong>sufficient <strong>in</strong>structions about handl<strong>in</strong>g, lack <strong>of</strong><br />
workers or tradesmen or subcontractors’ skill, difficulty <strong>in</strong> performance and<br />
pr<strong>of</strong>essional work, <strong>in</strong>teraction between various specialists and us<strong>in</strong>g untra<strong>in</strong>ed labors).<br />
In this thesis, we shall work on achiev<strong>in</strong>g the largest number <strong>of</strong> lean construction<br />
criteria because the project which was studied was completed. Waste <strong>in</strong> the value added<br />
process and non-value added process will be elim<strong>in</strong>ated or reduced. These wastes are<br />
particularly found <strong>in</strong> the project that was studied. Standardization and five why were the<br />
chosen tools to apply and implement lean construction <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong>.<br />
30
Chapter Three<br />
Methodology<br />
This chapter presents the methodology which was followed <strong>in</strong> this research.<br />
3.1 Research Strategy<br />
Quantitative and qualitative methods are used <strong>in</strong> this thesis. Quantitative data has been<br />
collected to measure the proportion <strong>of</strong> non-value added and the value added for time<br />
and steps <strong>in</strong> each process. This was measured by standardization tools, while qualitative<br />
data was used <strong>in</strong> order to understand the reasons <strong>of</strong> non-value added <strong>in</strong> the process by<br />
us<strong>in</strong>g the five why tools and giv<strong>in</strong>g solutions and suggestions for reduc<strong>in</strong>g the nonvalue<br />
added <strong>in</strong> construction.<br />
3.2 Data Collection<br />
To achieve the objectives <strong>of</strong> the current study, the researcher has used several sources.<br />
These <strong>in</strong>clude:<br />
3.2.1 Primary Sources<br />
Productivity data was obta<strong>in</strong>ed for Yahia (2004). Moreover 30 crafts men who have<br />
more than 10 years experience were <strong>in</strong>terviewed. The results obta<strong>in</strong>ed were compared<br />
with productivity data reported <strong>in</strong> the Center National <strong>of</strong> Animation Enterprises and<br />
Treatment <strong>of</strong> Information for Labor <strong>in</strong> Algeria Company. M<strong>in</strong>imum, the most likely and<br />
the maximum productivity <strong>of</strong> the resources are shown <strong>in</strong> (Table 3.1). In addition, the 5<br />
why were used to determ<strong>in</strong>e the causes <strong>of</strong> waste.<br />
31
Ma<strong>in</strong><br />
Activity<br />
Mobilization<br />
and excavation<br />
Pla<strong>in</strong> concrete<br />
Foundation<br />
work<br />
Neck column<br />
Back fill<strong>in</strong>g<br />
Ground beam<br />
Column work<br />
Ground floor<br />
Slab work<br />
Table 3.1 Productivity <strong>of</strong> resources <strong>in</strong> <strong>Gaza</strong> <strong>Strip</strong><br />
Activity<br />
process<br />
Excavation work M 3<br />
Form work M 3<br />
Cast pla<strong>in</strong> concrete M 3<br />
Remove form work M 3<br />
Form work M 3<br />
Fix neck column M 3<br />
Cast foundation M 3<br />
Remove form work M 3<br />
Form work M 3<br />
Cast concrete M 3<br />
Remove form work M 3<br />
First layer M 3<br />
Second layer M 3<br />
F<strong>in</strong>al layer M 3<br />
Form work M 3<br />
Cast concrete M 3<br />
Remove form work M 3<br />
Fix steel column M 3<br />
Form work M 3<br />
Cast concrete M 3<br />
Remove form work M 3<br />
Preparation work M 2<br />
Steel work M 2<br />
Mechanic work M 2<br />
Cast concert M 2<br />
Form work M 2<br />
Hollow cement<br />
Block work<br />
M 2<br />
Steel work M 2<br />
Electric work M 2<br />
Cast concrete M 2<br />
Remove form work M 2<br />
Unit M<strong>in</strong>imum<br />
32<br />
Unit/hours<br />
Most<br />
likely<br />
Maxim<br />
um<br />
57.69 62.5 68.18<br />
0.625 0.875 1<br />
0.75 0.875 1<br />
0.58 0.7 0.875<br />
0.625 0.875 1.125<br />
0.648 0.81 1.08<br />
5.77 6.5 12<br />
2.62 3.25 4.31<br />
0.072 0.083 0.147<br />
0.083 0.1 0.125<br />
0.31 0.375 0.46<br />
17.85 20.8 22.3<br />
25 31.25 41.66<br />
25 31.25 41.66<br />
0.28 0.4 0.58<br />
0.083 0.1 0.125<br />
0.7 0.93 1.125<br />
1.81 2.26 3<br />
0.176 0.2 0.35<br />
0.4 0.48 0.6<br />
1.51 1.81 2.26<br />
33.33 36.36 40<br />
14.28 14.81 15.38<br />
66.7 80 100<br />
66.7 80 100<br />
6.55 7.37 8.42<br />
9.83 11.8 14.75<br />
6.55 7.37 8.42<br />
6 8 12<br />
8 9 10<br />
4.91 5.9 7.37
Ma<strong>in</strong><br />
Activity<br />
Build<strong>in</strong>g work<br />
3.2.2 Secondary Sources<br />
Table 3.1 Case study productivity (Cont.)<br />
Activity<br />
process<br />
Build<strong>in</strong>g under the<br />
w<strong>in</strong>dow<br />
M 2<br />
L<strong>in</strong>tel work under<br />
w<strong>in</strong>dow<br />
ML<br />
Cast l<strong>in</strong>tel under the<br />
w<strong>in</strong>dows<br />
ML<br />
Remove form work ML<br />
Build<strong>in</strong>g beh<strong>in</strong>d the<br />
widows<br />
M 2<br />
L<strong>in</strong>tel work beh<strong>in</strong>d<br />
w<strong>in</strong>dow<br />
ML<br />
Cast l<strong>in</strong>tel up the<br />
w<strong>in</strong>dows<br />
ML<br />
Remove form work ML<br />
Build<strong>in</strong>g up the<br />
w<strong>in</strong>dow<br />
M 2<br />
Unit M<strong>in</strong>imum<br />
Unit/hours<br />
Most<br />
likely<br />
Maximum<br />
2.07 2.17 2.38<br />
15.91 19.1 23.87<br />
47.75 63.66 95.5<br />
23.87 31.83 47.75<br />
2.65 2.8 3.18<br />
15.91 19.1 23.87<br />
47.75 63.66 95.5<br />
47.75 31.83 93.87<br />
2.07 2.17 2.38<br />
The secondary sources <strong>in</strong>clude books, references, journals and magaz<strong>in</strong>es, and papers<br />
related to the research subject.<br />
3.3 Application <strong>of</strong> <strong>Lean</strong> Pr<strong>in</strong>ciples <strong>in</strong> <strong>Construction</strong><br />
Standardization was used to reduce the waste <strong>in</strong> the process by us<strong>in</strong>g the data <strong>of</strong> (Table<br />
3.1). The five why tools were used to identify the causes <strong>of</strong> waste and reduce the<br />
number <strong>of</strong> steps. The follow<strong>in</strong>g ten po<strong>in</strong>ts were used to def<strong>in</strong>e the biggest non- value<br />
added process <strong>in</strong> the project by us<strong>in</strong>g arena simulation <strong>in</strong> order to reduce non value<br />
added. More details <strong>of</strong> Arena Simulation are given <strong>in</strong> appendix (B).<br />
1. Select all non value-added activities <strong>in</strong> the simulation model (candidates for<br />
improvement). Use the def<strong>in</strong>ition provided by (Koskela, 1992) <strong>in</strong> the previous<br />
section to focus on activities that do not add value to the operation.<br />
2. Set the task durations <strong>of</strong> the improvement candidates to zero (one at a time).<br />
Although, <strong>in</strong> many cases, elim<strong>in</strong>at<strong>in</strong>g these activities is not possible or practical,<br />
do<strong>in</strong>g so will allow one to determ<strong>in</strong>e their significance on the model output.<br />
3. Produce simulation results (run the simulation).<br />
33
4. Sort the candidates <strong>in</strong> order <strong>of</strong> their significance to the simulation model. This will<br />
enable<br />
the improvement process to focus on those activities that have the greatest impact on<br />
model outputs.<br />
5. Look for practical activity reduction solutions for the candidates, start<strong>in</strong>g with the<br />
activity that has the greatest potential for improvement.<br />
6. Edit the simulation model to reflect zero-time delivery the biggest non value added<br />
activities. Although this may not be possible or practical, it will allow one to<br />
determ<strong>in</strong>e the effect on the project.<br />
7. Produce simulation results (run the simulation).<br />
8. Look for practical solutions to improve the material delivery processes (if required).<br />
If the material delivery process has a significant impact on model outputs, efforts<br />
should be made to make practical improvements.<br />
9. Look for practical solutions to improve production activities. Only after the lean<br />
concepts (value-added activities and pull-driven flow) have been <strong>in</strong>troduced to the<br />
model should the improvement be focused on production activities.<br />
10. Introduce buffers to compensate for <strong>in</strong>creased model variability and for differ<strong>in</strong>g<br />
production rates <strong>of</strong> l<strong>in</strong>ked operations. The lean production improvement process has<br />
generally been shown to <strong>in</strong>troduce significant variability <strong>in</strong>to processes. Buffers<br />
should be <strong>in</strong>troduced as a f<strong>in</strong>al step to compensate for this effect (Jack et al., 2004).<br />
34
Chapter Four<br />
Application<br />
<strong>Lean</strong> has been applied on a completed construction project <strong>of</strong> the construction because<br />
there is a lack <strong>of</strong> projects under construction. The project data are available and the<br />
project is <strong>of</strong> a medium size. The lean tools (standardization) are applied on this project<br />
and simulation has been applied to analyze the processes and activities duration.<br />
4.1. Project Description<br />
Table (4.1) shows <strong>in</strong>formation about the selected project.<br />
Table 4.1 Details <strong>of</strong> project<br />
No SUBJECT DATA<br />
1 Project name -<br />
2 Location -<br />
3 Owner -<br />
4 Contractor -<br />
5 Sub contractor -<br />
6<br />
Design consultant<br />
7 Site consultant -<br />
8 Donor The Islamic development bank- Jeddah<br />
9 Project area 3200 m 2<br />
10 Basement floor area 2370 m 2<br />
11 Ground floor area 2508 m 2<br />
12 First floor area 2420 m 2<br />
13 Start day 20/05/2004<br />
14 F<strong>in</strong>ish day 20/06/2006<br />
15 Real project duration 750days<br />
16 Contract duration 365 days<br />
17 Estimated cost <strong>of</strong> project 2,331,834.00 $<br />
35<br />
-
4.2 Project Activities<br />
<strong>Lean</strong> construction has been applied on the follow<strong>in</strong>g project activities <strong>in</strong> mobilization,<br />
pla<strong>in</strong> concrete, foundation, neck column, isolation, back fill<strong>in</strong>g, ground beam works,<br />
column for ground floor, ground floor, ground floor slab, first floor column, second<br />
floor slab, build<strong>in</strong>g for ground floor, and build<strong>in</strong>g works for first floor. The execution <strong>of</strong><br />
the project is divided <strong>in</strong>to three blocks A, B and C. Appendix (E).<br />
4.3 <strong>Lean</strong> Criteria Procedure<br />
The procedure <strong>of</strong> apply<strong>in</strong>g the lean pr<strong>in</strong>ciples is as follows:<br />
• Def<strong>in</strong><strong>in</strong>g the customer, the customer value, all resource required for construction,<br />
and all activities required for construction.<br />
• Identify non value added process (steps, time).<br />
• Remov<strong>in</strong>g or reduc<strong>in</strong>g the wastes <strong>in</strong> process by us<strong>in</strong>g the standardization and the<br />
five why tools to identify the cause <strong>of</strong> failure.<br />
• Identify<strong>in</strong>g non value added activities by apply<strong>in</strong>g the po<strong>in</strong>ts <strong>in</strong> figure 4.1 on the<br />
construction <strong>of</strong> El-Nasser New Pediatric Hospital project.<br />
• Improv<strong>in</strong>g the project until reach<strong>in</strong>g perfection.<br />
The above procedures are applied to the project as follows:<br />
The customer is the M<strong>in</strong>istry <strong>of</strong> Health. The value <strong>of</strong> customer is to construct the project<br />
with the same duration and cost and specification <strong>of</strong> contract.<br />
Only the follow<strong>in</strong>g eight po<strong>in</strong>ts <strong>in</strong> Figure (4.1) from the ten po<strong>in</strong>ts <strong>in</strong> section (3.3) were<br />
applied to the project because it is a completed construction project.<br />
36
Sett<strong>in</strong>g the process durations <strong>of</strong> the improvement candidates<br />
to zero (one at a time)<br />
Produc<strong>in</strong>g simulation result(run the simulation)<br />
Sort<strong>in</strong>g the candidates <strong>in</strong> order <strong>of</strong> their significance to<br />
the simulation model<br />
Look<strong>in</strong>g for practical activity reduction solutions<br />
for the candidates, start<strong>in</strong>g with the activity that has the<br />
greatest potential.<br />
Edit<strong>in</strong>g the simulation model to reflect zero-time on the<br />
biggest non value added process.<br />
Produc<strong>in</strong>g simulation results (run the simulation)<br />
Look<strong>in</strong>g for practical solutions to improve production activities. Only after<br />
the lean concepts (value-add<strong>in</strong>g activities and pull-driven flow) have been<br />
<strong>in</strong>troduced to the model should the improvement be focused on production<br />
activities.<br />
Introduce buffers to compensate for <strong>in</strong>creased<br />
model variability and for differ<strong>in</strong>g production<br />
rates <strong>of</strong> l<strong>in</strong>ked operations.<br />
Conclusion and recommendation<br />
Figure 4.1 Procedure <strong>of</strong> the application <strong>of</strong> lean pr<strong>in</strong>ciples<br />
37
Table 4.2 represents the resources, the duration for the process and the bill <strong>of</strong> the<br />
quantities <strong>of</strong> project by us<strong>in</strong>g Table (3.1). The follow<strong>in</strong>g resources are available<br />
throughout all the project period: Project manager (1), Site eng<strong>in</strong>eer (2), Foreman (1),<br />
Surveyor (1).<br />
Calculation <strong>in</strong> the last column was done as follows:<br />
Duration (hour) = Quantity/ ( Number <strong>of</strong> resources x Productivity x 8 hours)<br />
Maximum duration <strong>of</strong> the excavation process = 6000/ (1x 57x 8)= 13 hours.<br />
Most likely duration <strong>of</strong> the excavation process = 6000/ (1x 62x 8)= 12 hours.<br />
M<strong>in</strong>imum duration <strong>of</strong> the excavation process = 6000/ (1x 68x 8)= 11 hours.<br />
The rema<strong>in</strong><strong>in</strong>g processes were calculated <strong>in</strong> the same way.<br />
Ma<strong>in</strong><br />
Activity<br />
Mobilizatio<br />
n and<br />
excavation<br />
Pla<strong>in</strong><br />
concrete<br />
Foundation<br />
Neck<br />
column<br />
Process<br />
Table 4.2 Productivity <strong>of</strong> the project activities<br />
Excavation<br />
work<br />
Uni<br />
t<br />
M 3<br />
Form work M 2<br />
Cast pla<strong>in</strong><br />
concrete<br />
Remove<br />
form work<br />
M 2<br />
M2<br />
Form work M 3<br />
Fix neck<br />
column<br />
Cast<br />
foundation<br />
Remove<br />
form work<br />
Form work<br />
Cast<br />
concrete<br />
Remove<br />
form work<br />
M 3<br />
M 3<br />
M3<br />
M 3<br />
M 3<br />
M3<br />
Quantity<br />
6000<br />
No.<br />
resource<br />
1<br />
Excavator<br />
Productivity/*<br />
hour<br />
57, 62, 68<br />
140 5 workers 0.6, 0.8, 1<br />
140 5 workers 0.7, 0.8, 1<br />
140 5 workers 0.6, 0.7, 0.9<br />
935 9 workers 0.6, 0.9, 1<br />
935 9 workers 6, 8, 10<br />
935 9 workers 6 , 7 , 12<br />
935 9 workers 2, 3, 4<br />
60 8 workers<br />
60 8 workers<br />
0.07, 0.08,<br />
0.15<br />
0.08, 0.1,<br />
0.12<br />
60 8 workers 0.3, 0.4, 0.5<br />
Duration<br />
1day=8h<br />
11,12,13<br />
days<br />
3.5, 4.5.<br />
5.5<br />
days<br />
4,5,6<br />
hours<br />
3, 4, 5<br />
days<br />
11.5, 15,<br />
21 days<br />
1.5,2, 2.5<br />
days<br />
12, 16,18<br />
hours<br />
3, 4, 5<br />
days<br />
51, 90,<br />
103<br />
hours<br />
60, 75, 90<br />
m<strong>in</strong>ute<br />
16, 20, 24<br />
hours<br />
* This column shows the m<strong>in</strong>imum, most likely and maximum productivities accord<strong>in</strong>g<br />
to the bill quantity <strong>of</strong> the project.<br />
38
Ma<strong>in</strong><br />
Activity<br />
Back fill<strong>in</strong>g<br />
Ground beam<br />
Column<br />
work<br />
Ground floor<br />
Table 4.2 Productivity <strong>of</strong> the project activities(Cont.)<br />
Process Unit<br />
First<br />
layer<br />
M 3<br />
Second<br />
layer M 3<br />
F<strong>in</strong>al<br />
layer<br />
Form<br />
work<br />
Cast<br />
concrete<br />
Remove<br />
form<br />
work<br />
Fix steel<br />
column<br />
Form<br />
work<br />
Cast<br />
concrete<br />
Remove<br />
form<br />
work<br />
Preparati<br />
on work<br />
Steel<br />
work<br />
Mechanic<br />
work<br />
Cast<br />
concrete<br />
M 3<br />
M 3<br />
M 3<br />
M 3<br />
M 3<br />
M 3<br />
M 3<br />
M 3<br />
M 2<br />
M 2<br />
M 2<br />
M 2<br />
Quantity<br />
1000<br />
1000<br />
1000<br />
180<br />
180<br />
180<br />
145<br />
145<br />
145<br />
145<br />
2000<br />
2000<br />
2000<br />
2000<br />
39<br />
No.<br />
resource<br />
2<br />
excavator<br />
s<br />
2<br />
excavator<br />
s<br />
2<br />
excavator<br />
s<br />
8<br />
workers<br />
8<br />
workers<br />
8<br />
workers<br />
4<br />
workers<br />
4<br />
workers<br />
4<br />
workers<br />
4<br />
workers<br />
5<br />
workers<br />
5<br />
workers<br />
5<br />
workers<br />
5<br />
workers<br />
Productivity<br />
/hour<br />
18, 21, 22<br />
25, 31, 41<br />
25, 31, 41<br />
0.3, 0.4,<br />
0.6<br />
0.08, 0.1,<br />
0,12<br />
0.7, 0.9, 1<br />
1.8, 2, 3<br />
0.1, 0.2,<br />
0.3<br />
0.4, 0.5,<br />
0.6<br />
1.5, 1.8, 2<br />
33, 36, 40<br />
14, 15, 16<br />
60, 80,<br />
100<br />
60, 80,<br />
100<br />
Duration<br />
1day=8h<br />
2.5, 3,3.5<br />
days<br />
1.5, 2, 2.5<br />
days<br />
1.5, 2, 2.5<br />
days<br />
4.5, 7, 10<br />
days<br />
60, 75,90<br />
hours<br />
2.5, 3, 4<br />
days<br />
1.5, 2, 2.5<br />
days<br />
102, 180,<br />
206 hours<br />
60, 75, 90<br />
m<strong>in</strong>ute<br />
16, 20, 24<br />
hours<br />
10, 11, 12<br />
hours<br />
26, 27, 28<br />
hours<br />
4, 5 ,6<br />
hours<br />
4, 5 ,6<br />
hours
Ma<strong>in</strong><br />
Activity<br />
Slab work<br />
Build<strong>in</strong>g<br />
work<br />
Table 4.2 Productivity <strong>of</strong> the project activities(Cont.)<br />
Process<br />
Un<br />
it<br />
Form work M 2<br />
Hollow cement<br />
block<br />
M 2<br />
Steel work M 2<br />
Electric work M 2<br />
Cast concrete M 2<br />
Remove form<br />
work<br />
Build<strong>in</strong>g under the<br />
w<strong>in</strong>dow<br />
L<strong>in</strong>tel work under<br />
w<strong>in</strong>dow<br />
Cast l<strong>in</strong>tel under<br />
the w<strong>in</strong>dows<br />
Remove form<br />
work<br />
Build<strong>in</strong>g beh<strong>in</strong>d<br />
the widows<br />
L<strong>in</strong>tel work<br />
beh<strong>in</strong>d w<strong>in</strong>dow<br />
Cast l<strong>in</strong>tel up the<br />
w<strong>in</strong>dows<br />
Remove form<br />
work<br />
Build<strong>in</strong>g up the<br />
w<strong>in</strong>dow<br />
M 2<br />
M 2<br />
M<br />
L<br />
M<br />
L<br />
M<br />
L<br />
M 2<br />
M<br />
L<br />
M<br />
L<br />
M<br />
L<br />
M 2<br />
Quantity<br />
1180<br />
1180<br />
1180<br />
1180<br />
1180<br />
1180<br />
5730<br />
5730<br />
5730<br />
5730<br />
5730<br />
5730<br />
5730<br />
5730<br />
5730<br />
40<br />
No<br />
resource<br />
9<br />
workers<br />
9<br />
workers<br />
9<br />
workers<br />
4<br />
workers<br />
9<br />
workers<br />
9<br />
workers<br />
5<br />
workers<br />
5<br />
workers<br />
5<br />
workers<br />
5<br />
workers<br />
5<br />
workers<br />
5<br />
workers<br />
5<br />
workers<br />
5<br />
workers<br />
5<br />
workers<br />
Productiv<br />
ity/<br />
1hours<br />
6, 7, 8<br />
10, 12, 15<br />
6, 7, 8<br />
6, 8, 12<br />
Duration<br />
1day=8h<br />
(3.5, 4, 4.5)<br />
days<br />
(2, 2.5, 3)<br />
days<br />
(3.5, 4, 4.5)<br />
days<br />
(6, 8, 12)<br />
hours<br />
8, 9, 10 8, 9, 10hour<br />
5, 6, 7 4, 5, 6 days<br />
2, 2.5 ,3<br />
16, 19, 24<br />
20, 22, 23<br />
days<br />
2, 2.5, 3<br />
days<br />
48, 64, 95 4, 6, 8 hours<br />
24,32, 48<br />
2.5, 2.8, 3<br />
16, 19, 24<br />
1, 1.5, 2<br />
days<br />
15, 17, 18<br />
days<br />
2, 2.5, 3<br />
days<br />
48, 64, 95 4, 6, 8 hours<br />
24, 32, 48<br />
2, 2.5 ,3<br />
1, 1.5, 2<br />
days<br />
20, 22, 23<br />
days
4.4. Non-Value Added and Value Added Process Identification<br />
Activities can be classified as:<br />
1. Activity that adds value and can be def<strong>in</strong>ed as follows:<br />
• Activity which contributes to the customer's perceived value <strong>of</strong> the product<br />
or service (Convey et al., 1991).<br />
• Activity that “converts material and/or <strong>in</strong>formation towards what is required<br />
by the customer” (Koskela et al., 1992).<br />
2. Activity that does not add value and can be def<strong>in</strong>ed as follows:<br />
• Activity which, if elim<strong>in</strong>ated, would not detract from the customer's<br />
perceived value <strong>of</strong> the product or service (Saukkorriipi et al., 2004).<br />
• Activity which“takes time, resources and space but does not add value”<br />
Koskela et al., 1992).<br />
In the analysis <strong>of</strong> the project, the value added and non-value added times and steps <strong>of</strong><br />
the process can be def<strong>in</strong>ed as follows:<br />
• Value added time is the time that <strong>in</strong>creases the value duration <strong>of</strong> the process<br />
without any waste.<br />
• Non-value added time is the time that does not <strong>in</strong>crease the value added <strong>of</strong> the<br />
process without waste.<br />
• Value added steps are the steps that <strong>in</strong>crease the value <strong>of</strong> the work steps without<br />
any k<strong>in</strong>d <strong>of</strong> waste.<br />
• Non-value added steps are the steps that do not <strong>in</strong>crease the process value<br />
without waste.<br />
• Waste is a k<strong>in</strong>d <strong>of</strong> seven wastes over- production, defects, <strong>in</strong>ventory,<br />
transportation, wait<strong>in</strong>g, motion and over- process<strong>in</strong>g.<br />
Section 4.4.1 to 4.4.14 show the value and non value added processes <strong>of</strong> the project<br />
activities. The non value added takes “0” whereas value added takes number “1” or a<br />
fraction accord<strong>in</strong>g to the number <strong>of</strong> the steps <strong>in</strong> a process. For example section (4.4.1)<br />
the excavation process took two steps so the value added steps equal 1/2 +1/2 = 1. If the<br />
excavation was performed <strong>in</strong> one step, the value added <strong>of</strong> step takes “1”.<br />
41
4.4.1 Mobilization and excavation<br />
Table (4.3) shows seven processes where the number <strong>of</strong> value added steps is 1 out <strong>of</strong> 7<br />
steps which corresponds to14% <strong>of</strong> total steps. The total duration <strong>of</strong> the mobilization and<br />
excavation <strong>in</strong> the daily report is 240 hours.<br />
No.<br />
Table 4.3 Value and non-value added processes <strong>in</strong> mobilization and excavation<br />
Process<br />
Step<br />
number<br />
Step<br />
Value<br />
added<br />
steps<br />
Duration<br />
1day=<br />
8hours<br />
1 Site clean<strong>in</strong>g, <strong>in</strong>cludes remov<strong>in</strong>g trees 1 0 48<br />
2 Demolish<strong>in</strong>g the exist<strong>in</strong>g wall<strong>in</strong>g fence. 2 0 32<br />
3 To setup the site eng<strong>in</strong>eer <strong>of</strong>fice 3 0 32<br />
4<br />
Excavation <strong>of</strong> the natural ground to the<br />
required levels<br />
4 1/2 96<br />
5 Laboratory 5 0 8<br />
6 Expand the excavation 6 1/2 16<br />
7 Laboratory 7 0 8<br />
Total 7 1<br />
Percentage <strong>of</strong> value added steps 14%<br />
240<br />
4.4.2 Pla<strong>in</strong> concrete<br />
Table (4.4) shows the five processes that constitute the pla<strong>in</strong> concrete. The number <strong>of</strong><br />
value added steps is 1 out <strong>of</strong> 5 steps (20%) and the total duration <strong>in</strong> the daily report is 63<br />
hours.<br />
Table 4.4 Non-value added and value added processes <strong>in</strong> pla<strong>in</strong> concrete<br />
No.<br />
1<br />
2<br />
3<br />
4<br />
5<br />
Process<br />
Step<br />
number<br />
Steps<br />
Value<br />
added<br />
steps<br />
0<br />
1/2<br />
0<br />
1/2<br />
Cheblona work +form work concrete 1<br />
Cast <strong>in</strong> site 10cm thick pla<strong>in</strong> concrete 2<br />
Rework form work for foundation concrete 3<br />
Cast 3M3 pla<strong>in</strong> concrete 4<br />
Remove form work 5 0<br />
Total 5 1<br />
Percentage <strong>of</strong> value added steps 20%<br />
42<br />
Duration<br />
(hours)<br />
1day=<br />
8hours<br />
24<br />
16<br />
8<br />
5<br />
10<br />
63
4.4.3. Foundation<br />
Table (4.5) shows thirteen processes that constitute the foundation. Where the number<br />
<strong>of</strong> value added steps is 2 out <strong>of</strong> 13 steps (15%) and the total duration <strong>in</strong> the daily report<br />
is 276 hours.<br />
No.<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
13<br />
Table 4.5 Non-value added and value added processes <strong>in</strong> foundation<br />
Process<br />
Form work foundation concrete part "C"<br />
Form work foundation concrete part "A and<br />
"B"<br />
Fix steel <strong>of</strong> neck column part "A"<br />
Fix neck steel <strong>of</strong> neck column "B"<br />
Cast foundation "A"<br />
Remove form work part "A"+ form work<br />
part "C".<br />
Fix steel neck column part "C"<br />
Cast foundation part "B"<br />
Steel work for foundation part "C"<br />
Cast foundation part "B"<br />
Remove form work part "C"+ part "B".<br />
Form work for 5 foundation part "c", back<br />
fill<strong>in</strong>g<br />
Steel work +cast 5 foundation part "C" +<br />
back fill<strong>in</strong>g + steel work + Laboratory<br />
Total<br />
Percentage <strong>of</strong> value added steps<br />
43<br />
Step<br />
number<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
13<br />
13<br />
Step<br />
15%<br />
Value<br />
added<br />
steps<br />
0<br />
0<br />
1/4<br />
1/4<br />
1/4<br />
0<br />
1/4<br />
1/4<br />
1/4<br />
1/4<br />
0<br />
0<br />
1/4<br />
2<br />
Duration/<br />
hours<br />
1day=8hou<br />
rs<br />
88<br />
80<br />
28<br />
8<br />
8<br />
8<br />
4<br />
4<br />
8<br />
8<br />
8<br />
16<br />
8<br />
276
4.4.4 Neck column<br />
Table (4.6) shows thirteen processes that constitute the neck column. The number <strong>of</strong><br />
value added steps is 1 out <strong>of</strong> 13 steps (7.6%) and the total duration <strong>in</strong> the daily report is<br />
132 hours.<br />
No.<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
13<br />
Table 4.6 Non-value added and value added processes <strong>in</strong> neck column<br />
Process<br />
Re<strong>in</strong>forced concrete<br />
basement, remove walls form<br />
work<br />
Form work neck column ,<br />
wall concrete<br />
Justify the defect <strong>in</strong> the<br />
column.<br />
Cast wall concrete "A"<br />
Form work "B"<br />
Remove form work "A" neck<br />
column wall concrete+ "<br />
Neck column "B".<br />
Cast neck column "B"+<br />
Remove form work wall<br />
Form work part " C"<br />
Cast neck column part B.<br />
Cast neck column part C<br />
Remove form work +<br />
Cha<strong>in</strong><strong>in</strong>g<br />
Total<br />
Percentage <strong>of</strong> value added steps<br />
Step<br />
number<br />
44<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
13<br />
13<br />
Step<br />
Value<br />
added steps<br />
7.6%<br />
0<br />
0<br />
0<br />
0<br />
0<br />
0<br />
0<br />
1/3<br />
0<br />
0<br />
1/3<br />
1/3<br />
0<br />
1<br />
Duration<br />
(hours)<br />
1day=<br />
8hours<br />
2<br />
8<br />
54<br />
4<br />
2<br />
8<br />
8<br />
16<br />
2<br />
8<br />
10<br />
2<br />
8<br />
132
4.4.5 Isolation<br />
Table (4.7) shows two processes that constitute the isolation. The number <strong>of</strong> value<br />
added steps is 1 out <strong>of</strong> 2 steps (50 %) and the total duration <strong>in</strong> the daily report is 48<br />
hours.<br />
No.<br />
1<br />
Table 4.7 Non-value added and value added processes <strong>in</strong> isolation processes<br />
Clean<strong>in</strong>g<br />
Process<br />
2 Clean<strong>in</strong>g , isolation work<br />
Total<br />
Percentage <strong>of</strong> value added steps<br />
4.4.6 Back fill<strong>in</strong>g<br />
Step<br />
number<br />
1<br />
2<br />
2<br />
Steps<br />
50%<br />
Value<br />
added<br />
steps<br />
0<br />
1<br />
1<br />
Duration (hours)<br />
1day=8hours<br />
The six processes that represent backfill<strong>in</strong>g are shown <strong>in</strong> Table (4.8). The number <strong>of</strong><br />
value added steps is three out <strong>of</strong> six steps (50%) and the total duration <strong>in</strong> the daily report<br />
is 112 hours.<br />
Table 4.8 Non-value added and value added processes <strong>in</strong> back fill<strong>in</strong>g<br />
No.<br />
1<br />
2<br />
3<br />
Process<br />
Back fill<strong>in</strong>g layer1 + clean<strong>in</strong>g<br />
Laboratory<br />
Back fill<strong>in</strong>g layer 2<br />
4 Laboratory<br />
5 Back fill<strong>in</strong>g layer 3<br />
6 Laboratory<br />
Total<br />
Percentage <strong>of</strong> value added steps<br />
Step<br />
number<br />
45<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
6<br />
Step<br />
50%<br />
Value<br />
added<br />
steps<br />
1<br />
0<br />
1<br />
0<br />
1<br />
0<br />
3<br />
8<br />
40<br />
48<br />
Duration<br />
1day=8hours<br />
Duration<br />
Of process/<br />
hours<br />
48<br />
8<br />
32<br />
4<br />
16<br />
4<br />
112
4.4.7 Ground beam<br />
The twelve processes that represent ground beam are shown <strong>in</strong> Table (4.9). The number<br />
<strong>of</strong> value added steps is 6 out <strong>of</strong> 12 steps (50%) and the total duration <strong>in</strong> the daily report<br />
is 192 hours.<br />
Table 4.9 Non-value added and value added processes <strong>in</strong> ground beam<br />
No.<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
Step<br />
Process<br />
Step Value<br />
number added<br />
steps<br />
Form work for ground beam part A 1 0<br />
Form work for ground beam part B 2 0<br />
Back fill<strong>in</strong>g 3 1<br />
Form work for ground beam part C 4 0<br />
Steel work<br />
5 1<br />
Mechanical work<br />
6 1<br />
Earth electric<br />
7 1<br />
Caste ground part A,C<br />
8 1/2<br />
Remove form work part A<br />
9 0<br />
Isolation work<br />
10 1<br />
Cast G. beam part B<br />
11 1/2<br />
Remove form work<br />
12 0<br />
Total<br />
12 6<br />
Percentage <strong>of</strong> value added steps<br />
50%<br />
4.4.8 Ground floor column<br />
Duration<br />
(hours)<br />
1day=8hours<br />
Table (4.10) shows n<strong>in</strong>eteen processes where the number <strong>of</strong> value added steps is 2 out<br />
<strong>of</strong> 18 steps (10%) and the total duration <strong>of</strong> ground floor column <strong>in</strong> the daily report is<br />
346 hours.<br />
Table 4.10 Non-value added and value added processes for ground floor column<br />
No.<br />
1<br />
2<br />
3<br />
Process<br />
Steel work column part A, C.<br />
Form work column part A,C<br />
Check column before cast<strong>in</strong>g<br />
for part C<br />
46<br />
Step<br />
number<br />
1<br />
2<br />
3<br />
Step<br />
Value<br />
added steps<br />
1/2<br />
0<br />
0<br />
16<br />
48<br />
8<br />
60<br />
8<br />
8<br />
8<br />
8<br />
16<br />
4<br />
2<br />
6<br />
192<br />
Duration<br />
(hours)<br />
1day=<br />
8hours<br />
24<br />
96<br />
12
Table 4.10 Non-value added and value added processes for ground floor column (cont.)<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
13<br />
14<br />
15<br />
16<br />
17<br />
18<br />
Cast column part C.<br />
Check column part A<br />
Cast column part A<br />
Remove form work part A, C<br />
Steel work for column part B<br />
Form work column part B<br />
Check column part B<br />
Cast column part B<br />
Remove form work part B<br />
Remove 7 column(error work<br />
Steel work part B for the seven column<br />
Form work part B for the seven column<br />
Check<strong>in</strong>g the column<br />
Cast column<br />
Remove form work<br />
Total<br />
Percentage <strong>of</strong> value added steps<br />
4.4.9 Ground floor<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
13<br />
14<br />
15<br />
16<br />
17<br />
18<br />
18<br />
10%<br />
Table (4.11) shows seven processes where the number <strong>of</strong> value added steps is 3 out <strong>of</strong> 7<br />
steps (43 %) and the total duration <strong>in</strong> the daily report is 64 hours.<br />
No.<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
1/3<br />
0<br />
1/3<br />
0<br />
1/2<br />
0<br />
0<br />
1/3<br />
0<br />
0<br />
0<br />
0<br />
0<br />
0<br />
0<br />
2<br />
Table 4.11 Non-value added and value added processes for ground floor<br />
Process<br />
Mechanic work for part A,B,C<br />
Preparation work for part A,B<br />
Steel work for part A,B<br />
Cast ground floor for part A,B<br />
Preparation work for part C<br />
Steel work for part C<br />
Cast ground floor for part C<br />
Total<br />
Percentage <strong>of</strong> value added steps<br />
47<br />
Step<br />
number<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
7<br />
Steps<br />
43%<br />
Value<br />
added<br />
steps<br />
1<br />
0<br />
1/2<br />
1/2<br />
0<br />
1/2<br />
1/2<br />
3<br />
Duration<br />
(hours)<br />
1days=<br />
8hours<br />
8<br />
4<br />
12<br />
8<br />
16<br />
8<br />
8<br />
64<br />
8<br />
8<br />
8<br />
8<br />
12<br />
24<br />
8<br />
8<br />
16<br />
38<br />
8<br />
16<br />
8<br />
8<br />
36<br />
346
4.4.10 Ground floor slab<br />
The eleven processes that represent ground floor slab are shown Table (4.12). We notice<br />
that the number <strong>of</strong> value added steps is 4 out <strong>of</strong> 11 steps (36%) and the total duration <strong>in</strong><br />
the daily report is 168 hours.<br />
Table 4.12 Non-value added and value added processes <strong>in</strong> slab<br />
No. Process<br />
Step<br />
number<br />
Step<br />
Value added<br />
steps<br />
Duration<br />
/hours<br />
1 Form work for part A,B 1 0 48<br />
2 Hollow cement block for part A,B 2 1/2<br />
3 Electric work for part A,B 3 1/2<br />
4 Mechanical work for part A,B 4 1/2<br />
5 Cast slab ground floor part A,B 5 1/2<br />
6 Form work fort part C 6 0 32<br />
7 Hollow cement bloc for part C 7 1/2<br />
8 Electric work for part C 8 1/2<br />
9 Mechanical work for part C 9 1/2<br />
10 Cast slab for part C 10 1/2<br />
11 Remove form work for part A,B,C 11 0 26<br />
Total 11 4<br />
Percentage <strong>of</strong> value added steps 36%<br />
4.4.11 First floor columns<br />
Table (4.13) shows the twelve processes that constitute the first floor columns. The<br />
number <strong>of</strong> value added steps is 2 out <strong>of</strong> 12 steps (16 %) and the total duration <strong>in</strong> the<br />
daily report is 300 hours.<br />
48<br />
6<br />
6<br />
8<br />
8<br />
12<br />
8<br />
6<br />
8<br />
168
No.<br />
Table 4.13 Non-value added processes <strong>in</strong> first floor column<br />
Process<br />
1 Steel work column part A,C<br />
2 Form work column part A,C<br />
Check column before cast<strong>in</strong>g<br />
3<br />
for part C<br />
4 Cast column part C<br />
5 Check column part A.<br />
6 Cast column part A<br />
7 Remove form work part A, C<br />
8 Steel work for column part B<br />
9 Form work column part B<br />
10 Check column part B<br />
11 Cast column part B<br />
12 Remove form work part B<br />
Total<br />
Percentage <strong>of</strong> value added steps (%)<br />
4.4.12 First floor slab<br />
Step<br />
number<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
12<br />
Step<br />
16%<br />
Value added<br />
steps<br />
1/2<br />
0<br />
0<br />
1/3<br />
0<br />
1/3<br />
0<br />
1/2<br />
0<br />
0<br />
1/3<br />
0<br />
2<br />
Duration/<br />
hours<br />
1day=<br />
8hours<br />
The eleven processes that represent first floor slab are shown <strong>in</strong> Table (4.14). The<br />
number <strong>of</strong> value added steps is 4 out <strong>of</strong> 11 steps (36%) and the total duration <strong>in</strong> the<br />
daily report is 163 hours.<br />
No.<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
Table 4.14 Non-value added processes <strong>in</strong> first floor slab<br />
Process<br />
Step<br />
number<br />
Step<br />
Value added<br />
steps<br />
Duration<br />
1day=<br />
8hour<br />
Form work for part A,B 1<br />
0<br />
50<br />
Hollow cement block for<br />
part A,B<br />
2 1/2<br />
5<br />
Electric work for part<br />
A,B<br />
3 1/2<br />
4<br />
Mechanical work for part<br />
A,B<br />
4 1/2<br />
6<br />
Cast slab ground floor<br />
part A,B<br />
5<br />
1/2<br />
6<br />
Form work fort part C 6<br />
0<br />
34<br />
Hollow cement bloc for<br />
part C<br />
7<br />
1/2<br />
16<br />
Electric work for part C 8 1/2<br />
4<br />
49<br />
32<br />
88<br />
8<br />
7<br />
12<br />
6<br />
12<br />
14<br />
72<br />
6<br />
6<br />
37<br />
300
No.<br />
9<br />
10<br />
11<br />
Table 4.14 Non-value added processes <strong>in</strong> first floor slab (cont.)<br />
Process<br />
Mechanical work for part<br />
C<br />
Cast slab for part C<br />
Remove form work for<br />
part A,B,C<br />
Total<br />
4.4.13 Ground floor build<strong>in</strong>g<br />
Step<br />
number<br />
9<br />
10<br />
11<br />
11<br />
Step Duration<br />
Value added<br />
steps<br />
36%<br />
1/2<br />
1/2<br />
0<br />
4<br />
1day=<br />
8hour<br />
Table (4.15) shows eighteen processes where the number <strong>of</strong> value added steps is 5 out<br />
<strong>of</strong> 18 steps (27%) and the total duration <strong>of</strong> the ground floor build<strong>in</strong>g <strong>in</strong> the daily report<br />
is 560 hours<br />
Percentage <strong>of</strong> value added steps<br />
Table 4.15 Non-value added and value added processes <strong>in</strong> build<strong>in</strong>g for ground floor<br />
No.<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
13<br />
14<br />
15<br />
16<br />
17<br />
18<br />
Steps<br />
Build<strong>in</strong>g work <strong>in</strong> part A,B for first layer<br />
L<strong>in</strong>tel form work under the w<strong>in</strong>dows<br />
Cast l<strong>in</strong>tel<br />
Remove form work<br />
Build<strong>in</strong>g work for part A,B <strong>in</strong> the second<br />
layer<br />
L<strong>in</strong>tel form work up the w<strong>in</strong>dows<br />
Cast l<strong>in</strong>tel for second layer<br />
Remove form work<br />
Build<strong>in</strong>g work up the w<strong>in</strong>dow<br />
Build<strong>in</strong>g work <strong>in</strong> part C for first layer<br />
L<strong>in</strong>tel form work under the w<strong>in</strong>dows<br />
cast l<strong>in</strong>tel<br />
Remove form work<br />
Build<strong>in</strong>g work for part C <strong>in</strong> the second layer<br />
L<strong>in</strong>tel form work up the w<strong>in</strong>dows<br />
Cast l<strong>in</strong>tel for second layer<br />
Remove form work<br />
Build<strong>in</strong>g work up the w<strong>in</strong>dow<br />
Total<br />
Percentage <strong>of</strong> value added steps<br />
50<br />
Step<br />
number<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
13<br />
14<br />
15<br />
16<br />
17<br />
18<br />
18<br />
Step<br />
27%<br />
Value<br />
added<br />
steps<br />
1/2<br />
0<br />
1/2<br />
0<br />
1/2<br />
0<br />
1/2<br />
0<br />
1/2<br />
1/2<br />
0<br />
1/2<br />
0<br />
1/2<br />
0<br />
1/2<br />
0<br />
1/2<br />
5<br />
8<br />
6<br />
24<br />
163<br />
Duration<br />
(hours)<br />
56<br />
24<br />
6<br />
16<br />
72<br />
24<br />
8<br />
8<br />
48<br />
8<br />
48<br />
8<br />
80<br />
56<br />
16<br />
76<br />
24<br />
38<br />
560
4.4.14 First floor build<strong>in</strong>g<br />
Table (4.16) shows the eighteen processes that represent first floor build<strong>in</strong>g. The<br />
number <strong>of</strong> value added steps is 5 out <strong>of</strong> 18 steps (27%) and the total duration <strong>in</strong> the<br />
daily report is 550 hours.<br />
Table 4.16 Non-value added and value added processes <strong>in</strong> build<strong>in</strong>g for first floor<br />
No.<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
13<br />
14<br />
15<br />
16<br />
17<br />
18<br />
Steps<br />
Build<strong>in</strong>g work <strong>in</strong> part A,B for first<br />
layer<br />
L<strong>in</strong>tel form work under the w<strong>in</strong>dows<br />
cast l<strong>in</strong>tel<br />
Remove form work<br />
Build<strong>in</strong>g work for part A,B <strong>in</strong> the<br />
second layer<br />
L<strong>in</strong>tel form work up the w<strong>in</strong>dows<br />
Cast l<strong>in</strong>tel for second layer<br />
Remove form work<br />
Build<strong>in</strong>g work up the w<strong>in</strong>dow<br />
Build<strong>in</strong>g work <strong>in</strong> part C for first layer<br />
L<strong>in</strong>tel form work under the w<strong>in</strong>dows<br />
cast l<strong>in</strong>tel<br />
Remove form work<br />
Build<strong>in</strong>g work for part C <strong>in</strong> the<br />
second layer<br />
L<strong>in</strong>tel form work up the w<strong>in</strong>dows<br />
Cast l<strong>in</strong>tel for second layer<br />
Remove form work<br />
Build<strong>in</strong>g work up the w<strong>in</strong>dow<br />
Total<br />
Percentage <strong>of</strong> value added steps<br />
51<br />
Step<br />
number<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
13<br />
14<br />
15<br />
16<br />
17<br />
18<br />
18<br />
Steps<br />
27%<br />
Value<br />
added<br />
steps<br />
1/2<br />
0<br />
1/2<br />
0<br />
1/2<br />
0<br />
1/2<br />
0<br />
1/2<br />
1/2<br />
0<br />
1/2<br />
0<br />
1/2<br />
0<br />
1/2<br />
0<br />
1/2<br />
5<br />
Duration<br />
(hours)<br />
60<br />
16<br />
6<br />
12<br />
70<br />
24<br />
6<br />
6<br />
40<br />
12<br />
32<br />
10<br />
64<br />
32<br />
24<br />
64<br />
32<br />
40<br />
550
4.5 Remove or Reduce the Influence <strong>of</strong> Waste as it is Observed<br />
Simulation has been used <strong>in</strong> each activity to measure the duration and number <strong>of</strong> steps.<br />
Productivity data <strong>in</strong> Table (3.1) was used <strong>in</strong> the simulation model. Results are shown on<br />
Table (4.17). The full simulation results are shown <strong>in</strong> appendix (C).<br />
The results that were reached from mobilization and pla<strong>in</strong> concrete are expla<strong>in</strong>ed as<br />
follows ( the other activities use the same methodology).<br />
Figure (4.2) shows how lean is applied to mobilization and excavation activity. Firstly<br />
by us<strong>in</strong>g the five why tool. The steps were reduced from seven (Table 4.3) to three steps<br />
(Table 4.18). The seven steps are clean<strong>in</strong>g the site, demolish<strong>in</strong>g exist<strong>in</strong>g walls, build<strong>in</strong>g<br />
eng<strong>in</strong>eer's <strong>of</strong>fice, excavation work, check<strong>in</strong>g soil, extended excavation and check<strong>in</strong>g the<br />
new extension excavation land.<br />
The first three steps can be reduced to one step by coord<strong>in</strong>at<strong>in</strong>g clean<strong>in</strong>g, demolition<br />
and build<strong>in</strong>g. These three contractors can beg<strong>in</strong> work at the same time. The sixth and<br />
seventh steps can be avoided because there is a design error.<br />
Create 1<br />
0<br />
Clean<strong>in</strong>g Ex cav ation Laboratory<br />
0 0 0<br />
Dispose 1<br />
0<br />
0<br />
Figure 4.2 Arena simulation <strong>of</strong> mobilization and excavation<br />
Secondly, apply<strong>in</strong>g productivity to three processes. Clean<strong>in</strong>g lasted for 48 hours,<br />
demolition took 32 hours and build<strong>in</strong>g eng<strong>in</strong>eer's <strong>of</strong>fice took 32 hours. These three<br />
processes may start at the same time. S<strong>in</strong>ce the project was ready, the duration <strong>of</strong><br />
clean<strong>in</strong>g is supposed to be 48 hours (Table 4.3). This is considered non-value added<br />
process.<br />
52
Excavation data accord<strong>in</strong>g to Table (4.2) that shows the productivity <strong>of</strong> one excavator<br />
for 6000m 3 can be achieved <strong>in</strong> eleven days <strong>in</strong> m<strong>in</strong>imum limit and <strong>in</strong> twelve days most<br />
likely and <strong>in</strong> thirteen days maximum. This activity is considered value added process.<br />
The data is shown <strong>in</strong> Figure (4.3).<br />
Figure 4.3 Excavation process data<br />
Check<strong>in</strong>g soil process is done by contact<strong>in</strong>g the technicians <strong>in</strong> the material lab. The time<br />
it takes to get the results is six, eight, ten hours. This is also considered a non value<br />
added process. The data is shown as <strong>in</strong> Figure (4.4).<br />
Figure 4.4 Laboratory process data<br />
53
The result by us<strong>in</strong>g arena simulation replication 30 times is that clean<strong>in</strong>g took 48 hours.<br />
Non value added duration took 8.06 hours; non-value added process, excavation process<br />
took 95.29 hours a value added process. Results are shown <strong>in</strong> appendix ( C ).<br />
Figure (4.5) shows how lean is applied to pla<strong>in</strong> concrete activity after apply<strong>in</strong>g lean.<br />
The five why tool are used to identify the number <strong>of</strong> the steps <strong>in</strong> order to be reduced.<br />
Table (4.4) show five actual steps formwork, cast<strong>in</strong>g, remov<strong>in</strong>g formwork, cast 3 m 3,<br />
remove formwork. Table (4.19) shows that only three steps can be used by elim<strong>in</strong>at<strong>in</strong>g<br />
step four and five because they were ow<strong>in</strong>g to a design error.<br />
create<br />
0<br />
TNOW<br />
for m w ork cast<br />
remove form<br />
work<br />
Dispose 1<br />
0<br />
0<br />
0<br />
0<br />
Figure 4.5 Applied lean to pla<strong>in</strong> concrete activity<br />
Us<strong>in</strong>g standardization <strong>in</strong> Table ( 4.2) us<strong>in</strong>g 140m 2 , five craftsmen and ten workers, the<br />
productivity <strong>of</strong> formwork process was 3.5 days m<strong>in</strong>imum, 4 days most likely and 5.5<br />
days maximum (on eight-hours day work).<br />
Figure(4.6) shows formwork process that is considered non-value added. Average<br />
duration by 30 replications was 34.83 hours.<br />
Figure 4.6 Formwork pla<strong>in</strong> concrete data<br />
54<br />
0
The cast concrete data accord<strong>in</strong>g to Table (3.1) is found <strong>in</strong> Figure (4.7). This process is<br />
value added. The duration was 3.5 hours m<strong>in</strong>imum, 4 hours most likely, 4.5 hours<br />
maximum. Average duration for 30 replication was 3.97 hours.<br />
Figure 4.7 Cast<strong>in</strong>g pla<strong>in</strong> concrete process data<br />
Data <strong>of</strong> formwork removal process <strong>in</strong> Table (4.2) is <strong>in</strong>putted <strong>in</strong> Figure (4.8). This is a<br />
non-value added process. The average duration <strong>of</strong> 30 replications was 5.03 hours.<br />
Figure 4.8 Remove formwork process data<br />
55
Table 4.17 Simulation results<br />
No. Activity Process<br />
1 Mobilization<br />
2 Pla<strong>in</strong> concrete<br />
3 Foundation<br />
4 Column neck<br />
5<br />
Bitumen isolation<br />
6 Back fill<strong>in</strong>g<br />
V.A.Time 1<br />
(hours)<br />
N.V.A.Time 2<br />
(hours)<br />
Clean<strong>in</strong>g 0 48<br />
Excavation 95.29 0<br />
Laboratory 0 8.06<br />
Cast<strong>in</strong>g 3.97 0<br />
Form work 0 34.83<br />
Remove form work 0 5.03<br />
Fix steel 15.94 0<br />
Form work 0 129.6<br />
Cast<strong>in</strong>g 15.55 0<br />
Remove form work 0 31.34<br />
Form work 0 79.23<br />
Cast<strong>in</strong>g 1.26 0<br />
Remove form work 0 19.92<br />
Clean<strong>in</strong>g 0 11.86<br />
Isolation work 39.86 0<br />
Layer 1 23.47 0<br />
Layer 2 16.46 0<br />
Layer 3 15.82 0<br />
Laboratory 0 7.1<br />
Laboratory 0 3.57<br />
Laboratory 0 3.51<br />
1. V.A.Time: Value Added Time: Valued added time / hours<br />
2. N.V.A.Time: Non Value Added time/ hours.<br />
56
Table 4.17 Simulation results (Cont.)<br />
No. Activity Process<br />
7 Ground Beam<br />
8 Ground Floor<br />
9<br />
Column Work<br />
10 Slab Work<br />
11 Build<strong>in</strong>g Work<br />
.<br />
V.A.Time<br />
(hours)<br />
N.V.A.Time<br />
(hours)<br />
Form work 0 56.85<br />
Cast<strong>in</strong>g 4.19<br />
Remove form work 0 25.58<br />
Steel work 14 0<br />
Installation P.V.C 6.21 0<br />
Electrical work 11.76 0<br />
Cast<strong>in</strong>g 4.95 0<br />
Mechanical work 4.95 0<br />
Preparation 0 10.99<br />
Steel work 27.03 0<br />
Steel work 15.87 0<br />
Cast<strong>in</strong>g 1.23 0<br />
Form work 0 163.82<br />
Remove form work 0 19.68<br />
Cast<strong>in</strong>g 8.98 0<br />
Electrical Work 8.69 0<br />
Form work 0 31.58<br />
Hollow cement 19.85 0<br />
Remove form work 0 40.87<br />
Steel work 32.86 0<br />
Build<strong>in</strong>g 1 173.29 0<br />
Build<strong>in</strong>g 2 133.24 0<br />
Build<strong>in</strong>g 3 173.69 0<br />
Form work 1 0 19.62<br />
Form work 2 0 19.72<br />
Cast1 5.87 0<br />
Cast2 5.98 0<br />
Remove 1 0 11.72<br />
Remove2 0 11.88<br />
57<br />
0
Table 4.17 Simulation results (Cont.)<br />
No. Activity Processes<br />
12<br />
Column Work<br />
13 Slab Work<br />
14 Build<strong>in</strong>g Work<br />
.<br />
V.A.Time<br />
(hours)<br />
N.V.A.Time<br />
(hours)<br />
Steel work 16.56 0<br />
Cast<strong>in</strong>g 1.27 0<br />
Form work 0 157.51<br />
Remove form work 0 20.41<br />
Cast<strong>in</strong>g 8.9 0<br />
Electrical work 8.92 0<br />
Form work 0 31.51<br />
Hollow cement 20.32 0<br />
Remove form work 0 39.37<br />
Steel work 32.23 0<br />
Build<strong>in</strong>g 1 172.75 0<br />
Build<strong>in</strong>g 2 132.67 0<br />
Build<strong>in</strong>g 3 172.21 0<br />
Form work 1 0 20.07<br />
Form work 2 0 20.15<br />
Cast1 5.93 0<br />
Cast2 5.99 0<br />
Remove 1 0 12.44<br />
Remove2 0 11.88<br />
58
4.5.1 Mobilization and excavation<br />
Table (4.18) shows that mobilization and excavation duration is equal to 151.35 hours.<br />
Before apply<strong>in</strong>g lean tools, it was 240 hours, and the percentage <strong>of</strong> value added time<br />
was 63%, the actual percent value added duration was 39%, and value added steps after<br />
apply<strong>in</strong>g the five why tools is 33% (before apply<strong>in</strong>g lean tools was 14%). Step1 and 3<br />
are merged.<br />
No. Process<br />
1<br />
2<br />
Table 4.18 Waste elim<strong>in</strong>ation <strong>in</strong> mobilization<br />
Site clean<strong>in</strong>g, <strong>in</strong>cludes remov<strong>in</strong>g<br />
trees<br />
Demolish<strong>in</strong>g the exist<strong>in</strong>g wall<strong>in</strong>g<br />
fence, rooms and any obstructed<br />
item exist<strong>in</strong>g <strong>in</strong> the proposed area<br />
Step<br />
number<br />
1<br />
Step<br />
Value<br />
added<br />
steps<br />
0<br />
Duration<br />
<strong>of</strong> process<br />
(hours)<br />
48<br />
Duration<br />
Value<br />
added<br />
time<br />
(hours)<br />
3<br />
Excavation <strong>of</strong> the natural ground<br />
to the required levels<br />
2 1 95.29 95.29<br />
4 Laboratory 3 0 8.06 0<br />
Total 3 1 151.35 95.29<br />
Percentage <strong>of</strong> value added<br />
33% 63%<br />
4.5.2 Pla<strong>in</strong> concrete<br />
Table (4.19) shows that pla<strong>in</strong> concrete duration is equal to 41.09 hours. Before apply<strong>in</strong>g<br />
lean tools, it was 63 hours, and the percent <strong>of</strong> value added time 9%, the actual duration<br />
was 6%, and value added step percent is 33%. It was 20% before apply<strong>in</strong>g lean tools.<br />
No.<br />
Table 4.19 Waste elim<strong>in</strong>ation <strong>in</strong> pla<strong>in</strong> concrete<br />
Process<br />
1 formwork concrete for<br />
"A-B"<br />
2 Cast pla<strong>in</strong> concrete<br />
3 Remove form work<br />
Total<br />
Percentage <strong>of</strong> value added<br />
Step<br />
number<br />
Step<br />
Value<br />
added steps<br />
0<br />
1<br />
2 1<br />
3 0<br />
3 1<br />
33%<br />
59<br />
Duration<br />
<strong>of</strong> process<br />
(hours)<br />
34.83<br />
3.97<br />
5.037<br />
43.83<br />
Duration<br />
9%<br />
0<br />
Value<br />
added<br />
time<br />
(hours)<br />
0<br />
3.97<br />
0<br />
3.97
4.5.3 Foundation<br />
Table (4.20) shows that foundation duration is equal to 192.43 hours. Before apply<strong>in</strong>g<br />
lean tools, it was 276 hours and the percent <strong>of</strong> value added time was 16%, the actual<br />
duration was 10%, and value added step percent was 50%. It was 15% before apply<strong>in</strong>g<br />
lean tools.<br />
No.<br />
1<br />
2<br />
3<br />
4<br />
Process<br />
Form work foundation<br />
concrete "A-B-C" and<br />
steel.<br />
fix neck column "A-B-<br />
C"<br />
Cast Foundation "A-B-<br />
C"<br />
Remove form work<br />
Total<br />
Percentage <strong>of</strong> value added<br />
Table 4.20 Waste elim<strong>in</strong>ation <strong>in</strong> foundation<br />
Step<br />
number<br />
1<br />
2<br />
3<br />
Step<br />
Value<br />
added<br />
step<br />
0<br />
1<br />
1<br />
4 0<br />
4 2<br />
50%<br />
Duration<br />
<strong>of</strong><br />
process<br />
(hours)<br />
129.6<br />
15.94<br />
15.55<br />
31.34<br />
192.43<br />
Duration<br />
Value<br />
added<br />
time<br />
(hours)<br />
0<br />
15.94<br />
15.55<br />
0<br />
31.49<br />
16%<br />
4.5.4 Neck column<br />
Table (4.21) shows that neck column duration is equal to 100.41 hours, before apply<strong>in</strong>g<br />
lean tools was 132 hours, and the percent <strong>of</strong> value added time 1.2%, the actual duration<br />
was 0.8%, and value added step percent is 33 %, It was 8% before apply<strong>in</strong>g lean tools.<br />
Table 4.21 Waste elim<strong>in</strong>ation <strong>in</strong> neck column<br />
No.<br />
Process<br />
1 Form work neck column<br />
2 cast wall concrete "A"<br />
3 Remove form work<br />
Total<br />
Percentage <strong>of</strong> value added<br />
Step<br />
number<br />
Step<br />
Value<br />
added<br />
steps<br />
1 0<br />
2 1<br />
3 0<br />
3 1<br />
33 %<br />
60<br />
Duration<br />
/hours<br />
Duration<br />
79.23<br />
1.26<br />
19.92<br />
100.41<br />
1.2%<br />
Value<br />
Added<br />
time /<br />
hours<br />
0<br />
1.26<br />
0<br />
1.26
4.5.5 Isolation<br />
Table (4.22) shows that isolation duration is equal to 39.86 hours. Before apply<strong>in</strong>g lean<br />
tools was 48 hours, and the percent <strong>of</strong> value added time 100%, the actual duration was<br />
82%, and value added step percent is 100 %. It was 50% before apply<strong>in</strong>g lean tools.<br />
No.<br />
Process<br />
1 Isolation work<br />
clean<strong>in</strong>g<br />
Total<br />
Percentage <strong>of</strong> value added<br />
Table 4.22 Waste elim<strong>in</strong>ation <strong>in</strong> isolation<br />
Step<br />
number<br />
1<br />
Steps<br />
Value added<br />
steps<br />
1<br />
Duration<br />
(hours)<br />
39.86<br />
Duration<br />
Value added<br />
time (days)<br />
39.86<br />
1 1 39.86 39.86<br />
100 % 100 %<br />
4.5.6 Back fill<strong>in</strong>g<br />
Table (4.23) shows that backfill<strong>in</strong>g duration is equal to 69.93 hours. Before apply<strong>in</strong>g<br />
lean tools was 112 hours, and the percent <strong>of</strong> value added time 79.7%, the actual<br />
duration was 49%, and value added step percent is 100 %. It was 50% before apply<strong>in</strong>g<br />
lean tools.<br />
No.<br />
Table 4.23 Waste elim<strong>in</strong>ation for back fill<strong>in</strong>g<br />
Process<br />
1 Back fill<strong>in</strong>g layer1,<br />
clean<strong>in</strong>g site<br />
2 Laboratory<br />
3 Back fill<strong>in</strong>g layer 2<br />
4 Laboratory<br />
5 Back fill<strong>in</strong>g layer 3<br />
6 Laboratory<br />
Total<br />
Percentage <strong>of</strong> value added<br />
Step<br />
number<br />
1<br />
Step<br />
Value<br />
added<br />
step<br />
1<br />
Duration<br />
(hours)<br />
23.47<br />
Duration<br />
Value<br />
added<br />
time<br />
(days)<br />
23.47<br />
2 0 7.1 0<br />
3 1 16.46 16.46<br />
4 0 3.57 0<br />
5 1 15.82 15.82<br />
6 0 3.51 0<br />
6 3 69.93 55.75<br />
50% 79.7%<br />
61
4.5.7 Ground beam<br />
Table (4.24) shows that ground beam duration is equal to 118.59 hours. Before apply<strong>in</strong>g<br />
lean tools was 192 hours, and the percent <strong>of</strong> value added time 30%, the actual duration<br />
was 20%, and value added step percent is 67 %. It was 50% before apply<strong>in</strong>g lean tools.<br />
No.<br />
1<br />
2<br />
3<br />
4<br />
Table 4.24 Waste elim<strong>in</strong>ation for ground beam<br />
Process<br />
Form work for ground<br />
beam "A-B-C"<br />
Steel work<br />
Install and test<br />
UPVC+ earth electric<br />
Earth electric work<br />
5 Caste ground beam<br />
6 Remove form work<br />
Total<br />
Percentage <strong>of</strong> value added<br />
4.5.8 Column ground floor<br />
Step<br />
number<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
6<br />
Step<br />
67%<br />
Value<br />
added step<br />
0<br />
1<br />
1<br />
1<br />
1<br />
0<br />
4<br />
Duration<br />
(hours)<br />
56.85<br />
14<br />
6.21<br />
11.76<br />
Duration<br />
Value<br />
added<br />
time<br />
0<br />
14<br />
6.21<br />
11.76<br />
4.19 4.19<br />
25.58 0<br />
118.59 36.16<br />
30%<br />
Table (4.23) shows that column ground floor duration is equal to 200.6 hours. Before<br />
apply<strong>in</strong>g lean tools was 346 hours, and the percent <strong>of</strong> value added time 8.5%, the actual<br />
duration was 4.7%, and value added step percent is 50 %. It was 10% before apply<strong>in</strong>g<br />
lean tools.<br />
No.<br />
Table 4.25 Waste elim<strong>in</strong>ation for ground floor column<br />
Process<br />
1 Steel work<br />
2 Form work<br />
3 Cast column<br />
4 Remove form work<br />
Total<br />
Percentage <strong>of</strong> value added<br />
Step<br />
numb<br />
er<br />
1<br />
2<br />
3<br />
4<br />
4<br />
Step<br />
50%<br />
62<br />
Value<br />
creatio<br />
n step<br />
1<br />
0<br />
1<br />
0<br />
2<br />
Duration<br />
(hours)<br />
15.87<br />
163.82<br />
1.23<br />
19.68<br />
200.6<br />
Duration<br />
Value<br />
added<br />
time (hours)<br />
15.87<br />
0<br />
1.23<br />
0<br />
17.1<br />
8.5%
4.5.9 Ground floor<br />
Table (4.26) shows that ground floor duration is equal to 47.56 hours. Before apply<strong>in</strong>g<br />
lean tools was 64 hours, and the percent <strong>of</strong> value added time 77%, the actual duration<br />
was 55%, and value added step percent is 75 %. It was 57% before apply<strong>in</strong>g lean tools.<br />
No.<br />
Table 4.26 Waste elim<strong>in</strong>ation for ground floor<br />
Process<br />
1 Preparation work<br />
2 Steel work<br />
3 Mechanical work<br />
4 Cast concrete<br />
Total<br />
Percentage <strong>of</strong> value<br />
added<br />
Step<br />
number<br />
1<br />
2<br />
3<br />
4<br />
4<br />
Step<br />
75%<br />
Value<br />
added<br />
step<br />
0<br />
1<br />
1<br />
1<br />
3<br />
Duration<br />
10.99<br />
27.03<br />
4.95<br />
4.59<br />
47.56<br />
Duration<br />
77%<br />
Value<br />
added<br />
time<br />
0<br />
27.03<br />
4.95<br />
4.59<br />
36.57<br />
4.5.10 Ground floor slab<br />
Table (4.27) shows that slab ground floor duration is equal to 142.83 hours. Before<br />
apply<strong>in</strong>g lean tools was 168 hours, and the percent <strong>of</strong> value added time 49% the actual<br />
duration was 41%, and value added step percent is 67 %. It was 44% before apply<strong>in</strong>g<br />
lean tools.<br />
No.<br />
Table 4.27 Waste elim<strong>in</strong>ation for ground floor slab<br />
Process<br />
1 Form work<br />
2 Hollow cement block<br />
3 Steel work<br />
Electric + mechanic<br />
4<br />
work<br />
5 Cast concrete<br />
6 Remove form work<br />
Total<br />
Percentage <strong>of</strong> value added<br />
Step<br />
number<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
6<br />
63<br />
Step<br />
67%<br />
Value<br />
added step<br />
0<br />
1<br />
1<br />
1<br />
1<br />
0<br />
4<br />
Duration<br />
31.58<br />
19.85<br />
32.86<br />
8.69<br />
Duration<br />
Value<br />
added<br />
time<br />
0<br />
19.85<br />
32.86<br />
8.69<br />
8.98 8.98<br />
40.87 0<br />
142.83 70.38<br />
49%
4.5.11 Column first floor<br />
Table (4.28) shows that column first floor duration is equal to 195.75 hours. Before<br />
apply<strong>in</strong>g lean tools was 346 hours, and the percent <strong>of</strong> value added time 9%, the actual<br />
duration was 4.7%, and value added step percent is 50 %.It was 10 % before apply<strong>in</strong>g<br />
lean tools.<br />
No.<br />
Table 4.28 Waste elim<strong>in</strong>ation <strong>in</strong> first floor column<br />
Process<br />
1 Steel work<br />
2 Form work column<br />
3 Cast column<br />
4 Remove form work<br />
Total<br />
Percentage <strong>of</strong> value added<br />
Step<br />
number<br />
1<br />
2<br />
3<br />
4<br />
4<br />
Step<br />
Value<br />
added step<br />
Duration<br />
(hours)<br />
Duration<br />
1 16.56<br />
- 157.51<br />
1 1.27<br />
- 20.41<br />
2 195.75<br />
50% 9%<br />
Value<br />
added<br />
time (hours)<br />
16.56<br />
0<br />
1.27<br />
0<br />
17.83<br />
4.5.12 First floor slab<br />
Table (4.29) shows that slab first floor duration is equal to 140.53 hours. Before<br />
apply<strong>in</strong>g lean tools was 168 hours, and the percent <strong>of</strong> value added time 50%, the actual<br />
duration was 44%, and value added step percent is 67 %. It was 41% before apply<strong>in</strong>g<br />
lean tools.<br />
No.<br />
Table 4.29 Waste elim<strong>in</strong>ation for first floor slab<br />
Process<br />
1 Form work<br />
2 Hollow cement block<br />
3 Steel work<br />
4 Electric, mechanic<br />
work<br />
5 Cast concrete<br />
6 Remove form work<br />
Total<br />
Percentage <strong>of</strong> value added<br />
Step<br />
number<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
6<br />
64<br />
Step<br />
Value<br />
added step<br />
67%<br />
0<br />
1<br />
1<br />
1<br />
1<br />
0<br />
4<br />
Duration<br />
31.51<br />
20.32<br />
32.23<br />
8.92<br />
8.9<br />
39.37<br />
140.53<br />
Duration<br />
Value<br />
Added<br />
Time (hrs)<br />
0<br />
20.32<br />
32.23<br />
8.92<br />
8.9<br />
0<br />
70.37<br />
50%
4.5.13 Build<strong>in</strong>g <strong>in</strong> ground floor<br />
Table (4.30) shows that build<strong>in</strong>g ground floor duration is equal to 554.91 hours. Before<br />
apply<strong>in</strong>g lean tools was 560 hours, and the percent <strong>of</strong> value added time 88%, the actual<br />
duration was 87%, and value added step percent was 55 %. It was 26% before apply<strong>in</strong>g<br />
lean tools.<br />
Table 4.30 Waste elim<strong>in</strong>ation for ground floor build<strong>in</strong>g<br />
Step<br />
Duration<br />
No. Process Step<br />
number<br />
Value<br />
added<br />
step<br />
Duration<br />
(hours)<br />
Value<br />
Added<br />
Time (hrs)<br />
1 Build<strong>in</strong>g work<br />
1 1 173.29 173.29<br />
2 Form work<br />
2 0 19.62 0<br />
3 Cast l<strong>in</strong>tel<br />
3 1<br />
5.87 5.87<br />
4 Remove form work 4 0 11.72 0<br />
5 build<strong>in</strong>g work 2<br />
5 1 133.24 133.24<br />
6 L<strong>in</strong>tel work form<br />
work 1<br />
6 - 19.62 0<br />
7 Cast l<strong>in</strong>tel<br />
7 1 5.98 5.98<br />
8 Remove form work 8 - 11.88 0<br />
9 Build<strong>in</strong>g work 3 9 1 173.69 173.69<br />
Total<br />
9 5 554.91 492.07<br />
Percentage <strong>of</strong> value added<br />
55%<br />
88%<br />
4.5.14 Build<strong>in</strong>g <strong>in</strong> first floor<br />
Table (4.31) shows that build<strong>in</strong>g first floor duration is equal to 553.37 hours. Before<br />
apply<strong>in</strong>g lean tools was 560 hours, and the percent <strong>of</strong> value added time 88%, the actual<br />
duration was 87%, and value added step percent is 55 %. It was 26% before apply<strong>in</strong>g<br />
lean tools.<br />
Table 4.31 Waste elim<strong>in</strong>ation for first floor build<strong>in</strong>g<br />
Step<br />
Duration<br />
No. Process<br />
Step<br />
numb<br />
er<br />
Value<br />
added<br />
step<br />
Duration<br />
(hours)<br />
Value<br />
Added<br />
Time (hrs)<br />
1 Build<strong>in</strong>g work<br />
1 1 172.75 172.75<br />
2 Form work<br />
2 0 20.07 0<br />
3 Cast l<strong>in</strong>tel<br />
3 1 5.93 5.93<br />
4 Remove form work 4 0 11.72 0<br />
5 Build<strong>in</strong>g work 2 5 1 132.67 132.67<br />
6 L<strong>in</strong>tel work form work 6 0 20.1 0<br />
7 Cast l<strong>in</strong>tel<br />
7 1 5.99 5.99<br />
8 Remove form work 8 0 11.88 0<br />
9 Build<strong>in</strong>g work 3 9 1 172.21 172.21<br />
Total<br />
9 5 553.37 489.55<br />
Percentage <strong>of</strong> value added 55%<br />
88%<br />
65
4.6 Identify the Cause <strong>of</strong> Waste<br />
Table (4.32) shows the difference between activity before and after apply<strong>in</strong>g lean <strong>in</strong><br />
order to demonstrate the effect <strong>of</strong> lean on the activity and also to identify the activities<br />
that can be improved. The difference column (PVAT) is <strong>in</strong> descend<strong>in</strong>g order.<br />
Table 4.32 Difference between activity before and after lean application<br />
No. Activity<br />
Before apply<strong>in</strong>g<br />
lean<br />
PVAS 3<br />
(%)<br />
PVAT 4<br />
%<br />
After apply<strong>in</strong>g<br />
lean<br />
PVAS<br />
(%)<br />
PVAT<br />
%<br />
Difference<br />
PVAS<br />
(%)<br />
PVAT<br />
%<br />
1 Back fill<strong>in</strong>g 50 49 50 79.7 0 30.7<br />
2 Mobilization 14 39 33 63 19 24<br />
3 Ground floor 57 57 75 77 18 20<br />
4 Isolation 50 82 100 100 50 18<br />
5 Ground beam 43 18.8 67 30 24 11.2<br />
6<br />
7<br />
Slab work <strong>in</strong><br />
first floor<br />
Slab work<br />
ground floor<br />
36 41 67 50 31 9<br />
36 41 67 49 31 8<br />
8 Foundation 15 11 50 16 35 5<br />
9<br />
Column first<br />
floor<br />
10 Column<br />
ground floor<br />
11 Pla<strong>in</strong><br />
concrete<br />
Build<strong>in</strong>g<br />
12 work <strong>in</strong><br />
13<br />
ground floor<br />
Build<strong>in</strong>g<br />
work <strong>in</strong> first<br />
Floor<br />
10 5 50 9 40 4<br />
10 4.9 50 8.5 40 3.6<br />
20 6 33 9 13 3<br />
26 87 55 88 29 1<br />
26 87 55 88 29 1<br />
14 Neck column 8 1 33 1 25 0<br />
3. Percent value added time.<br />
4. Percent value added steps.<br />
66
Figure (4.9) is divided <strong>in</strong>to four quarters.<br />
In the first quarter, little improvement <strong>in</strong> value added steps which produces high<br />
improvement <strong>in</strong> value added time <strong>in</strong> the backfill<strong>in</strong>g, ground floor, mobilization and<br />
excavation activities. The backfill<strong>in</strong>g activity was 0% <strong>in</strong> the value added steps and<br />
30.7% <strong>in</strong> value added time. This happened by avoid<strong>in</strong>g the delay <strong>of</strong> the work <strong>of</strong> the<br />
excavator which stopped for a certa<strong>in</strong> period <strong>of</strong> time. Stopp<strong>in</strong>g was due to an error <strong>in</strong><br />
the design. The production <strong>of</strong> the excavator was not satisfactory because the foremen<br />
were absent. The mobilization and excavator activities <strong>in</strong>crease by 19% <strong>in</strong> value added<br />
steps and 26% <strong>in</strong> value added time by avoid<strong>in</strong>g the unclear design. Ground floor activity<br />
<strong>in</strong>creased by 18% <strong>in</strong> value added steps and 20% <strong>in</strong> value added time by <strong>in</strong>creas<strong>in</strong>g the<br />
management experience.<br />
In the second quarter, a slight improvement <strong>in</strong> value added steps led to the same<br />
improvement <strong>in</strong> value added time. The ground beam activity raised by 17% <strong>in</strong> value<br />
added steps and 11% <strong>in</strong> value added time. The pla<strong>in</strong> concrete activity <strong>in</strong>creased by 3%<br />
<strong>in</strong> value added time because the percentage <strong>of</strong> non value added activity <strong>of</strong> the formwork<br />
and remov<strong>in</strong>g it, are less than value added activity.<br />
In the third quarter, the big improvement <strong>in</strong> value added steps gave only a little<br />
improvement <strong>in</strong> the value added time. The value added steps <strong>in</strong> the slab activity has<br />
raised by 23% and the value added time raised by 8%. The value added steps for the<br />
columns activity raised by 40% and value added time 3.6%. The number <strong>of</strong> the steps <strong>of</strong><br />
the neck columns improved by 25% and the value added time did not improve. The<br />
number <strong>of</strong> steps <strong>of</strong> build<strong>in</strong>g activity improved by 29% and value added time by 1%.<br />
This all happened because the non value added processes (form work and remov<strong>in</strong>g it)<br />
had a big time value <strong>in</strong>side the activity.<br />
In the fourth quarter, a big improvement <strong>in</strong> the value steps produced big improvement <strong>in</strong><br />
the value added time. The number <strong>of</strong> steps <strong>in</strong> the isolation activity <strong>of</strong> the value added<br />
steps rose by 50% that also rose the value added time by 18%. These rises happened<br />
because clean<strong>in</strong>g process was done after remov<strong>in</strong>g the formwork. It was done dur<strong>in</strong>g the<br />
work <strong>of</strong> the contractor because <strong>of</strong> the lack <strong>of</strong> workers and the clean<strong>in</strong>g material.<br />
67
Percent <strong>of</strong> value add<strong>in</strong>g time<br />
35%<br />
30%<br />
25%<br />
20%<br />
15%<br />
10%<br />
5%<br />
0%<br />
2<br />
1<br />
0% 10% 20% 30% 40% 50% 60%<br />
Percent <strong>of</strong> value add<strong>in</strong>g steps<br />
Figure 4.9 Compar<strong>in</strong>g value added steps to value added time<br />
Regard<strong>in</strong>g the causes <strong>of</strong> delays <strong>of</strong> activities, us<strong>in</strong>g the five why tools showed the<br />
follow<strong>in</strong>g results:<br />
• The failure due to design error was 30.7%.<br />
• The failure due to work error was 24%.<br />
• The failure due to lack <strong>of</strong> experienced management was 20%.<br />
4<br />
• The failure due to lack <strong>of</strong> resources was 18% due to lack <strong>of</strong> permanent<br />
resources.<br />
• The failure due to lack <strong>of</strong> material formwork was 8% because the contractor<br />
had to divide the project <strong>in</strong>to many stage because <strong>of</strong> lack <strong>of</strong> the formwork. The<br />
solution is to save enough formwork. Figure (4.10) shows the percentage <strong>of</strong><br />
the causes <strong>of</strong> a failure as <strong>in</strong> the diagram.<br />
68<br />
3
Percent <strong>of</strong> non value added<br />
process<br />
35<br />
30<br />
25<br />
20<br />
15<br />
10<br />
5<br />
0<br />
Design error Work error Lack <strong>of</strong><br />
experience<br />
Lack <strong>of</strong> number<br />
<strong>of</strong> ressources<br />
Cause <strong>of</strong> non value added process<br />
Figure 4.10 Cause <strong>of</strong> failure<br />
4.7 F<strong>in</strong>d<strong>in</strong>g the Largest Non-Value Added Process<br />
Lack <strong>of</strong><br />
material<br />
The eight po<strong>in</strong>ts that were mentioned <strong>in</strong> the methodology (4.3) were applied us<strong>in</strong>g arena<br />
simulation <strong>in</strong> order to f<strong>in</strong>d the biggest non value added process. The whole non value<br />
added process is shown <strong>in</strong> Table (4.33) by putt<strong>in</strong>g “0” non value added process <strong>in</strong> turn<br />
and calculat<strong>in</strong>g the time period <strong>in</strong> the end <strong>of</strong> the project (run the simulation Figure<br />
(4.11)).<br />
TNOW<br />
Create 2<br />
MOBILIZATION<br />
0<br />
PLAIN CONCRETE FOUNDATION NICK COLUMN ISOLATION DEMOLITION<br />
GROUND BEAM COLUMN1 GROUND FLOOR Slab work<br />
build<strong>in</strong>g work1 build<strong>in</strong>g work2 Dispose 2<br />
Figure 4.11 Simulation model<br />
69<br />
0<br />
Column2 SLAB2
Table 4.33 Total project duration<br />
No. Process<br />
Non value added Time<br />
=0<br />
1<br />
Mobilization and<br />
excavation<br />
Site clean<strong>in</strong>g<br />
Laboratory<br />
0<br />
0<br />
2<br />
Pla<strong>in</strong> concrete<br />
Form work concrete<br />
Remove form work<br />
0<br />
0<br />
3<br />
Foundation<br />
Form work concrete<br />
Remove form work<br />
0<br />
0<br />
4<br />
Neck column<br />
Form work concrete<br />
Remove form work<br />
0<br />
0<br />
5 Isolation Clean<strong>in</strong>g 0<br />
6 Back fill<strong>in</strong>g<br />
Laboratory <strong>of</strong> layer1<br />
Laboratory <strong>of</strong> layer2<br />
0<br />
0<br />
Laboratory <strong>of</strong> layer3 0<br />
7 Ground beam<br />
Form work concrete<br />
Remove form work<br />
0<br />
0<br />
8 Column ground floor<br />
Form work concrete<br />
Remove form work<br />
0<br />
0<br />
9. Ground floor Preparation work 0<br />
10 Slab work ground floor<br />
Form work concrete<br />
Remove form work<br />
0<br />
0<br />
11 Column first floor<br />
Form work concrete<br />
Remove form work<br />
0<br />
0<br />
12 Slab work first floor<br />
Form work concrete<br />
Remove form work<br />
0<br />
0<br />
Form work concrete 0<br />
13<br />
Build<strong>in</strong>g work <strong>in</strong> ground<br />
floor<br />
Remove form work<br />
Form work concrete<br />
0<br />
0<br />
Remove form work 0<br />
Form work concrete 0<br />
14 Build<strong>in</strong>g work <strong>in</strong> first floor<br />
Remove form work<br />
Form work concrete<br />
0<br />
0<br />
Remove form work 0<br />
70<br />
Total<br />
duration<br />
2951.3<br />
2991.3<br />
2964.5<br />
2994.3<br />
2869.7<br />
2968<br />
2920.1<br />
2979.4<br />
2992.2<br />
2995.8<br />
2995.8<br />
2942.5<br />
2973.8<br />
2835.5<br />
2979.7<br />
2988.3<br />
2967.8<br />
2958.5<br />
2841.8<br />
2978.9<br />
2967.8<br />
2960<br />
2979.7<br />
2987.6<br />
2979.6<br />
2987.5<br />
2979.3<br />
2986.9<br />
2979.2<br />
2987.5<br />
2951.3
Then the candidates have been sorted out <strong>in</strong> order <strong>of</strong> their significance duration based<br />
on simulation results. This enables the improvement process to focus on those activities<br />
that have the greatest impact on model outputs (Table 4.34).<br />
Table 4.34 Activities <strong>in</strong> a descend<strong>in</strong>g order based on duration<br />
No. Activity Non- value added<br />
Total<br />
duration(hours)<br />
1 Column ground floor Form work concrete 2835.5<br />
2 Column first floor Form work concrete 2841.8<br />
3 Foundation Form work concrete 2869.7<br />
4 Neck column Form work concrete 2920.1<br />
5 Ground beam Form work concrete 2942.5<br />
6 Mobilization and Site clean<strong>in</strong>g 2951.3<br />
7 Slab work ground floor Remove form work 2958.5<br />
8 slab work first floor Remove form work 2960<br />
9 Pla<strong>in</strong> concrete Form work concrete 2964.5<br />
10 Slab work ground floor Form work concrete 2967.8<br />
11 slab work first floor Form work concrete 2967.8<br />
12 Foundation Remove form work 2968<br />
13 Ground beam Remove form work 2973.8<br />
14 Column first floor Remove form work 2978.9<br />
15 Build<strong>in</strong>g work <strong>in</strong> first floor Form work concrete 2979.2<br />
16 Build<strong>in</strong>g work <strong>in</strong> first floor Form work concrete 2979.3<br />
17 Neck column Remove form work 2979.4<br />
18 Build<strong>in</strong>g work <strong>in</strong> ground Form work concrete 2979.6<br />
19 Column ground floor Remove form work 2979.7<br />
20 Build<strong>in</strong>g work <strong>in</strong> ground Form Work Concrete 2979.7<br />
21 Build<strong>in</strong>g work <strong>in</strong> first floor Remove form work 2986.9<br />
22 Build<strong>in</strong>g work <strong>in</strong> ground Remove form work 2987.5<br />
23 Build<strong>in</strong>g work <strong>in</strong> first floor Remove form work 2987.5<br />
24 Build<strong>in</strong>g work <strong>in</strong> ground Remove form work 2987.6<br />
25 Ground floor Preparation work 2988.3<br />
26 Mobilization and Laboratory 2991.3<br />
27 Back fill<strong>in</strong>g Laboratory <strong>of</strong> layer1 2992.2<br />
28 Pla<strong>in</strong> concrete Remove form work 2994.3<br />
29 Back fill<strong>in</strong>g Laboratory <strong>of</strong> layer2 2995.8<br />
30 Back fill<strong>in</strong>g Laboratory <strong>of</strong> layer3 2995.8<br />
71
Then, the processes with the greatest impact on the project duration are identified and<br />
shown <strong>in</strong> Table (4.35).<br />
Calculated <strong>of</strong> the value added percent is as follows:<br />
V.A. Percent=Value added / Total duration<br />
Value added accord<strong>in</strong>g the appendix (c)=1906.15 hours<br />
V.A.Percent <strong>of</strong> the form work the ground floor column = 1906.15 / 2835.5 = 67%.<br />
V.A.Percent <strong>of</strong> the form work the first floor column = 1906.15 / 2841.8 = 67%.<br />
V.A.Percent <strong>of</strong> the form work the foundation = 1906.15 / 2869.7 = 66%.<br />
No. Process<br />
Table 4.35 Greatest duration <strong>of</strong> waste <strong>in</strong> activity<br />
Non value added<br />
Total<br />
duration<br />
(hours)<br />
V.A<br />
Percent<br />
(%)<br />
1 Ground floor column Form work concrete 2835.5 67%<br />
2 First floor column Form work concrete 2841.8 67%<br />
Foundation Form work concrete<br />
3 2869.7 66%<br />
In case <strong>of</strong> putt<strong>in</strong>g “0” for the three process, the results are shown <strong>in</strong> Table (4.36).The<br />
full simulation result is shown <strong>in</strong> appendix (D).<br />
Calculated <strong>of</strong> the value added percent is as follows:<br />
Value added percent = 1906.15 / 2563.05 = 74%<br />
No.<br />
1<br />
Table 4.36 Project duration without the most wast<strong>in</strong>g activity<br />
Process<br />
Non- value<br />
added process<br />
Foundation Form work Concrete<br />
Ground floor column Form work Concrete<br />
First floor column Form work Concrete<br />
72<br />
Total<br />
duration<br />
(hours)<br />
2563.05<br />
V.A<br />
Percent<br />
(%)<br />
74%
F<strong>in</strong>ally, buffers are <strong>in</strong>troduced to balance the processes duration.<br />
Figure (4.12) shows that duration <strong>of</strong> the foundation formwork process is 129.6 hours.<br />
This is far from the other processes (shown as number eight). Ground floor columns<br />
formwork process duration are 163.82. First floor columns formwork process duration<br />
was 157.51 hours. These are longer than the other processes (shown as number 34, 53).<br />
The duration <strong>of</strong> the build<strong>in</strong>g processes took 173.29, 133.2, 173.69, 172.75, 132.67,<br />
172.21 hours. These numbers correspond to 42, 43, 44, 61, 62, 63. These duration are<br />
larger than those <strong>in</strong> the other processes.<br />
Duration (hours)<br />
200<br />
180<br />
160<br />
140<br />
120<br />
100<br />
80<br />
60<br />
40<br />
20<br />
0<br />
Non value added process Value added process<br />
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67<br />
Process<br />
Figure (4.12) Duration variability before <strong>in</strong>troduc<strong>in</strong>g buffers and after apply<strong>in</strong>g lean<br />
tools<br />
Table (4.37) shows the balance improvement <strong>in</strong>to the process by decreas<strong>in</strong>g the duration<br />
<strong>of</strong> processes. Foundation formwork process duration decreased from 129.6 hours to<br />
42.6 hours by <strong>in</strong>creas<strong>in</strong>g the number <strong>of</strong> resources from 9 to 27 workers shown as<br />
number eight <strong>in</strong> Figure (4.13). The duration <strong>of</strong> excavation process decreased from 95.29<br />
to 45 hours by us<strong>in</strong>g 2 excavators shown as number three. The duration <strong>of</strong> the ground<br />
floor columns formwork decreased from 163.82 hours to 56.49 hours by <strong>in</strong>creas<strong>in</strong>g the<br />
number <strong>of</strong> workers to12 workers shown as number 34. The first floor columns<br />
formwork duration decreased from 157.51 hours to 56.49 hours by <strong>in</strong>creas<strong>in</strong>g the<br />
73
number <strong>of</strong> workers to 12 workers shown as number 53. The ground floor build<strong>in</strong>g<br />
duration decreased from 173.29, 133.24, 173.96 hours to 65.9, 66.07, 66.37 hours by<br />
<strong>in</strong>creas<strong>in</strong>g the number <strong>of</strong> workers to 13, 10, 13 workers shown as number 42, 43, 44.<br />
The first floor build<strong>in</strong>g duration decreased from 172.75, 132.67, 172.21 hours to 65.9,<br />
66.07, 66.37 hours by <strong>in</strong>creas<strong>in</strong>g the number <strong>of</strong> workers to 13, 10, 13 workers shown as<br />
number 61, 62, 63.<br />
The result <strong>of</strong> <strong>in</strong>troduc<strong>in</strong>g buffer is that the non-value added time decreased by 55%<br />
(from 1906.15 hours to 846.5 hours).<br />
Activity Process<br />
Mobil.<br />
Pla<strong>in</strong><br />
Table 4.37 Balanc<strong>in</strong>g the process<br />
Before <strong>in</strong>troduc<strong>in</strong>g buffers After <strong>in</strong>troduc<strong>in</strong>g buffers<br />
New<br />
resources<br />
number<br />
VA<br />
hours<br />
NVA<br />
hours<br />
New<br />
resources<br />
number<br />
New<br />
V.A.<br />
New<br />
NVA<br />
Check - 0 8.06 - 0 8.06<br />
Clean<strong>in</strong>g - 0 48 - 0 48<br />
Excavation<br />
concret. Remove<br />
Found.<br />
Neck<br />
1<br />
Excavator<br />
95.29 0<br />
2<br />
Excavator<br />
45 0<br />
Cast<strong>in</strong>g 5 3.97 0 5 3.97 0<br />
Form Work 5 0 34.83 5 0 34.83<br />
form<br />
5 0 5.03 5 0 5.03<br />
Fix steel 9 15.94 0 9 15.94 0<br />
Form work 9 0 129.6 27 0 42.6<br />
Cast<strong>in</strong>g 9 15.55 0 9 15.5 0<br />
Remove<br />
Formwork<br />
Column Remove<br />
formwork<br />
9 0 31.34 9 0 31.3<br />
Formwork 8 0 79.23 14 0 67.29<br />
Cast<strong>in</strong>g 8 1.26 0 8 1.26 0<br />
8 0 19.92 8 0 19.9<br />
74
Activity Process<br />
Isolation Isolation<br />
Backfill<strong>in</strong>g<br />
Ground<br />
beam<br />
Table 4.37 Balanc<strong>in</strong>g the process (cont.)<br />
Before <strong>in</strong>troduc<strong>in</strong>g buffers<br />
NRN<br />
VA<br />
hours<br />
NVA<br />
hours<br />
After <strong>in</strong>troduc<strong>in</strong>g<br />
NRN<br />
buffers<br />
New<br />
V.A.<br />
New<br />
NVA<br />
Clean<strong>in</strong>g 2 0 11.86 2 0 11.8<br />
work<br />
Layer 1<br />
Layer 2<br />
Layer 3<br />
2 39.86 0 2<br />
2<br />
Excavato<br />
r<br />
2<br />
Excavat.<br />
2<br />
Excavat.<br />
23.47 0<br />
16.46 0<br />
15.82 0<br />
2<br />
Excav.<br />
2<br />
Excav.<br />
2<br />
Excav.<br />
39.8<br />
6<br />
23.4<br />
7<br />
16.4<br />
6<br />
15.8<br />
2<br />
Laboratory 1 - 0 7.1 - 0 7.1<br />
Laboratory 2 - 0 3.57 - 0 3.57<br />
Laboratory 3 - 0 3.51 - 0 3.51<br />
Form Work 8 0 56.85 16 0 29.85<br />
Cast<strong>in</strong>g 8 4.19 0 8 4.19 0<br />
Remove form 8 0 25.58 8 0 25.58<br />
Steel work 8 14 0 8 14 0<br />
Install. PVC 8 6.21 0 8 6.21 0<br />
11.7<br />
Electrical 8 11.76 0 8 0<br />
6<br />
75<br />
0<br />
0<br />
0<br />
0
Activity Process<br />
Ground<br />
floor<br />
Column<br />
work<br />
Slab<br />
work<br />
ground<br />
floor<br />
Build<strong>in</strong>g<br />
ground<br />
floor<br />
Table 4.37 Balanc<strong>in</strong>g the process (cont.)<br />
Before <strong>in</strong>troduc<strong>in</strong>g buffers After <strong>in</strong>troduc<strong>in</strong>g buffers<br />
NRN<br />
VA<br />
hours<br />
NVA<br />
hours<br />
NRN<br />
New<br />
V.A.<br />
Cast<strong>in</strong>g 5 4.95 0 5 4.95 0<br />
Mechanical<br />
work<br />
New<br />
NVA<br />
5 4.95 0 5 4.95 0<br />
Preparation 5 0 10.99 5 0 10.99<br />
Steel work 5 27.03 0 5 27.03 0<br />
Steel work 4 15.87 0 4 15.87 0<br />
Cast<strong>in</strong>g 4 1.23 0 4 1.23 0<br />
Form work 4 0 163.82 12 0 56.49<br />
Remove form<br />
Work<br />
4 0 19.68 4 0 19.68<br />
Cast<strong>in</strong>g 9 8.98 0 9 8.98 0<br />
Electrical<br />
work<br />
9 8.69 0 9 8.69 0<br />
Form work 9 0 31.58 9 0 31.58<br />
Hollow<br />
cement<br />
Remove form<br />
work<br />
9 19.85 0 9 19.85 0<br />
9 0 40.87 11 0 32.47<br />
Steel work 9 32.86 0 9 32.86 0<br />
Build<strong>in</strong>g 1 5 173.29 0 13 65.9 0<br />
Build<strong>in</strong>g 2 5 133.24 0 10 66.07 0<br />
Build<strong>in</strong>g 3 5 173.69 0 13 66.37 0<br />
Form work 1 5 0 19.62 5 0 19.62<br />
Form work 2 5 0 19.72 5 0 19.72<br />
Cast1 5 5.87 0 5 5.87 0<br />
Cast2 5 5.98 0 5 5.98 0<br />
Remove 1 5 0 11.72 5 0 11.72<br />
Remove2 5 0 11.88 5 0 11.88<br />
76
Activity Process<br />
Column<br />
work first<br />
floor<br />
.<br />
Slab work<br />
first floor<br />
Build<strong>in</strong>g<br />
work<br />
first floor<br />
Table 4.37 Balanc<strong>in</strong>g process (Cont.)<br />
Before <strong>in</strong>troduc<strong>in</strong>g buffers After <strong>in</strong>troduc<strong>in</strong>g buffers<br />
NRN<br />
VA<br />
hours<br />
NVA<br />
hours<br />
NRN<br />
New<br />
V.A.<br />
Steel work 5 16.56 0 5 16.56 0<br />
Cast<strong>in</strong>g 5 1.27 0 5 1.27 0<br />
New<br />
NVA<br />
Form work 5 0 157.51 12 0 56.49<br />
Remove<br />
form<br />
5 0 20.41 5 0 20.41<br />
Cast<strong>in</strong>g 9 8.9 0 9 8.9 0<br />
Electrical<br />
work<br />
9 8.92 0 9 8.92 0<br />
Form work 9 0 31.51 9 0 31.51<br />
Hollow<br />
cement<br />
Remove<br />
form work<br />
9 20.32 0 9 20.32 0<br />
9 0 39.37 11 0 32.47<br />
Steel work 9 32.23 0 9 32.23 0<br />
Build<strong>in</strong>g 1 5 172.75 0 13 65.9 0<br />
Build<strong>in</strong>g 2 5 132.67 0 10 66.07 0<br />
Build<strong>in</strong>g 3 5 172.21 0 13 66.37 0<br />
Form work 1 5 0 20.07 5 0 20.07<br />
Form work 2 5 0 20.15 5 0 20.15<br />
Cast1 5 5.93 0 5 5.93 0<br />
Cast2 5 5.99 0 5 5.99 0<br />
Remove 1 5 0 12.44 5 0 12.44<br />
Remove2 5 0 11.88 5 0 11.88<br />
77
Actual project duration was 6000 hours.<br />
Actual non-value added duration <strong>of</strong> total process was 4892.17 hours.<br />
Total duration, before <strong>in</strong>troduc<strong>in</strong>g buffer, was 3013.98 hours.<br />
Value added duration <strong>of</strong> total process before <strong>in</strong>troduc<strong>in</strong>g buffer was1906.15.<br />
Total duration after <strong>in</strong>troduc<strong>in</strong>g buffer was 1503.43 hours.<br />
Non value added duration <strong>of</strong> total process after <strong>in</strong>troduc<strong>in</strong>g buffer was 846.5 hours.<br />
80<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
Non value added processes Value added processes<br />
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69<br />
Process<br />
Figure (4.13) Duration variability after Introduc<strong>in</strong>g buffers<br />
The contract<strong>in</strong>g time duration was 2920 hours. After apply<strong>in</strong>g lean tools the total<br />
duration was 1503.15.<br />
Table (4.38) shows the cycle time decrease from 6000 hours to 1503.43 hours<br />
(reduction by 75%).<br />
Table 4.38 Cycle time compared<br />
Activity<br />
Total<br />
duration<br />
Actual<br />
duration<br />
hours<br />
Application<br />
<strong>of</strong> lean tools<br />
Cycle time after<br />
<strong>in</strong>troduc<strong>in</strong>g buffer<br />
Duration (hours) % Duration(hours) %<br />
6000 3013.98 50%<br />
78<br />
1503.43 75%
4.8 Application <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong> for Future <strong>Construction</strong> Project<br />
In order to apply lean construction on future projects, we have to apply the follow<strong>in</strong>g<br />
po<strong>in</strong>ts:<br />
1. To improve master schedule <strong>of</strong> the project by us<strong>in</strong>g standardization tool<br />
2. To hold a weekly meet<strong>in</strong>g and to determ<strong>in</strong>e percent plan complete (PPC) <strong>of</strong><br />
the process <strong>of</strong> the assignment by evaluation <strong>of</strong> the steps. Advancement <strong>of</strong> the<br />
project can be measured every 4 weeks or 6 weeks accord<strong>in</strong>g to the size <strong>of</strong><br />
the project. The average must be more than 80%. Later on the change <strong>of</strong><br />
average may become very simple.<br />
3. To apply the 5 why tool to identify the ma<strong>in</strong> reasons <strong>of</strong> failure.<br />
4. Correct<strong>in</strong>g and avoid<strong>in</strong>g any previous failure <strong>in</strong> the follow<strong>in</strong>g week.<br />
5. To measure the average <strong>of</strong> the percent plan complete <strong>in</strong> each 4 weeks, the<br />
weekly meet<strong>in</strong>g will be good if the percent plan complete is more than 80%.<br />
6. To identify, remove or reduce the non-value added process<br />
7. To make a cont<strong>in</strong>uous improvement.<br />
Apply<strong>in</strong>g the above po<strong>in</strong>ts to the mobilization and excavation activity described <strong>in</strong><br />
project studied: clean<strong>in</strong>g work, cutt<strong>in</strong>g trees, demolition exist<strong>in</strong>g wall <strong>in</strong> the site,<br />
build<strong>in</strong>g an eng<strong>in</strong>eer<strong>in</strong>g <strong>of</strong>fice, excavation work first layer, excavation second layer, and<br />
excavation third layer. Table 4.39 shows the process completed and the process<br />
assigned <strong>in</strong> the master schedule <strong>of</strong> a real project. In the 1 st , 2 nd , 3 rd week there are two<br />
assigned process (clean<strong>in</strong>g, cutt<strong>in</strong>g trees) and only one was completed. In the 4 th and 5 th<br />
week there are three assigned (clean<strong>in</strong>g, cutt<strong>in</strong>g trees, demolition) and only two<br />
processes were completed. In the 6 th and 7 th week there are four assigned and only<br />
three processes were completed. In the 8 th and 9 th week, there are five assigned and only<br />
four processes were completed. In the 10 th week, there are 6 assigned and only 5<br />
processes were completed. In the 11 th week there are 7 assigned and only 5 processes<br />
were completed.<br />
79
Date<br />
Process<br />
Assigned<br />
Process<br />
Completed<br />
Table 4.39 Process assigned and process completed<br />
1 st<br />
Week<br />
2 nd<br />
Week<br />
3 rd<br />
Week<br />
4 th<br />
Week<br />
5 th<br />
Week<br />
6 th<br />
W.<br />
7 th<br />
W.<br />
8 th<br />
W.<br />
9 th<br />
W.<br />
10 th<br />
2 2 2 3 3 4 4 5 5 6 7<br />
1 1 1 2 2 3 3 4 4 5 5<br />
Figure (4.14) shows the real percentage plan complete <strong>of</strong> each week.<br />
PPC=(Number <strong>of</strong> processes completed / Number <strong>of</strong> processes assigned) X 100<br />
In the 1 st , 2 nd , 3 rd weeks, the PPC=1/2 x100=50%. In the 4 th week, 5 th week the PPC =<br />
2/3 x100 = 66%, <strong>in</strong> the 6 th week, 7 th week the PPC= 3/4x100= 75%. %. In the 4 th week,<br />
5 th week the PPC = 2/3 x 100 = 66%, <strong>in</strong> the 8 th week, 9 th week the PPC= 4/5 x 100<br />
=80%. In the 10 th week the PPC = 80%, <strong>in</strong> the 11 th week the PPC= 70%. This needs to<br />
determ<strong>in</strong>e the ma<strong>in</strong> reasons <strong>of</strong> failure.<br />
Us<strong>in</strong>g the five why tool, the cause <strong>of</strong> failure is the lack <strong>of</strong> experienced management and<br />
the lack <strong>of</strong> number <strong>of</strong> resources.<br />
0.9<br />
0.8<br />
0.7<br />
0.6<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
Week 1 Week<br />
2<br />
Week<br />
3<br />
Week<br />
4<br />
Week<br />
5<br />
Week<br />
6<br />
Week<br />
7<br />
Week<br />
8<br />
Week<br />
9<br />
Week<br />
10<br />
Figure 4.14 Actual percent plan complete <strong>of</strong> each week (PPC)<br />
80<br />
W.<br />
Week<br />
11<br />
11 th<br />
W.
Figure (4.15) shows the average <strong>of</strong> percent plan complete is smaller than 80% which<br />
requires f<strong>in</strong>d<strong>in</strong>g out failure reasons <strong>in</strong> each week. By the application <strong>of</strong> the five why<br />
tools and the 10 po<strong>in</strong>ts described <strong>in</strong> part (3.3).<br />
0.9<br />
0.8<br />
0.7<br />
0.6<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
w eekly percent plan complete Average percent plan complete<br />
Week 1 Week<br />
2<br />
Week<br />
3<br />
Week<br />
4<br />
Week<br />
5<br />
Week<br />
6<br />
Week<br />
7<br />
Week<br />
8<br />
Week<br />
9<br />
Week<br />
10<br />
Figure 4.15 Average percent plan complete <strong>of</strong> each four week<br />
81<br />
Week<br />
11
5.1 Conclusion<br />
Chapter Five<br />
Conclusion and Recommendations<br />
This study <strong>of</strong> <strong>Lean</strong> <strong>Construction</strong> <strong>Practices</strong> <strong>in</strong> the <strong>Gaza</strong> <strong>Strip</strong> shows the <strong>in</strong>fluence <strong>of</strong><br />
apply<strong>in</strong>g the lean construction. This study was conducted by identify<strong>in</strong>g criteria <strong>of</strong> lean<br />
construction and apply<strong>in</strong>g standardization tools, 5 why tools, 10 po<strong>in</strong>t to achieve the<br />
lean pr<strong>in</strong>ciple <strong>in</strong> reduc<strong>in</strong>g the activity steps and duration by elim<strong>in</strong>at<strong>in</strong>g the non value<br />
added process <strong>in</strong> the activity by us<strong>in</strong>g the arena simulation. The follow<strong>in</strong>g consequences<br />
have been reached:<br />
1. Value added time <strong>in</strong>creased from 49% to 63% as a result <strong>of</strong> apply<strong>in</strong>g lean tools.<br />
2. The used lean tools decrease the cycle time from 6000 hours to 1503.43 hours<br />
(decreased by 75%).<br />
3. The value added can be enhanced to 74% by improv<strong>in</strong>g the form work material <strong>in</strong><br />
foundation (us<strong>in</strong>g prefabricated) and column activities ( steel form work).<br />
4. The number <strong>of</strong> steps decreased from 161 to 69 (a reduced by 57%).<br />
5. Non -value added duration <strong>of</strong> total process was 4892.17 hours (81%) ; it decreased<br />
to 846.5 hours ( 14% decrease).<br />
6. <strong>Lean</strong> construction through standardization tools reduces the variability <strong>of</strong> the<br />
process, example the excavation work for one hour (57m 3 , 62m 3 , 68m 3 ).<br />
7. The rate <strong>of</strong> no value added process related to the design error was 30.7%. This has<br />
been considered the biggest value <strong>of</strong> the no value added <strong>in</strong> the process s<strong>in</strong>ce it<br />
happens dur<strong>in</strong>g the stage <strong>of</strong> design, therefore, we must apply the lean <strong>in</strong> the design<br />
to avoid waste dur<strong>in</strong>g the construction.<br />
8. The percentage <strong>of</strong> the no value added <strong>in</strong> the process due the above mentioned<br />
reasons were as follow: Rework 24% lack <strong>of</strong> experience management 20%, lack <strong>of</strong><br />
number <strong>of</strong> resources 18%, lack <strong>of</strong> material 8%. This requires tra<strong>in</strong><strong>in</strong>g workers.<br />
Eng<strong>in</strong>eers, other managers, supervisors should beg<strong>in</strong> suitable courses <strong>in</strong><br />
management. It is favorable to work with a permanent technical staff <strong>in</strong> the<br />
company. Efficient resources, sufficient materials should be provided and saved for<br />
the project.<br />
82
5.2 Recommendations<br />
In order to apply lean construction tools and achieve its benefits successfully, the<br />
follow<strong>in</strong>g recommendations should be considered:<br />
1. Us<strong>in</strong>g standardization tool <strong>in</strong> companies.<br />
2. Tra<strong>in</strong><strong>in</strong>g the workers <strong>in</strong> the company <strong>in</strong> order to reach the needed productivity<br />
which has big effects on the improvement <strong>of</strong> work.<br />
3. Us<strong>in</strong>g the 5 why tools to identify the errors and their causes to avoid them and not<br />
look<strong>in</strong>g for the mistaken people.<br />
4. Focus<strong>in</strong>g on this study as a first step to use the lean <strong>in</strong> construction projects.<br />
5. Apply<strong>in</strong>g the methodology used <strong>in</strong> the current study to all companies <strong>in</strong> the <strong>Gaza</strong><br />
<strong>Strip</strong>.<br />
6. Improv<strong>in</strong>g the master schedule <strong>of</strong> the project by standardization tools and measur<strong>in</strong>g<br />
the percent plan complete for each process to deal with errors weekly.<br />
7. Process evaluation and project progress should be measured every 4 weeks as<br />
mentioned <strong>in</strong> the last planner tools.<br />
8. The percent plan complete average <strong>of</strong> lean project must be more than 80%.<br />
9. After prov<strong>in</strong>g the potential application, lean studies should focus on obstacles <strong>of</strong><br />
lean implementation.<br />
83
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88
Appendix A Daily Report.<br />
Appendix B Arena Simulation.<br />
List <strong>of</strong> Appendices<br />
Appendix C Simulation result <strong>of</strong> the project before apply<strong>in</strong>g eight po<strong>in</strong>ts and after<br />
apply<strong>in</strong>g lean tools.<br />
Appendix D Simulation Result after apply<strong>in</strong>g "0" for three biggest non-value added<br />
processes <strong>of</strong> the project dur<strong>in</strong>g apply<strong>in</strong>g eight po<strong>in</strong>ts.<br />
89
Appendices (A)<br />
Daily report<br />
Date Activity<br />
26/06/2003 Site clean<strong>in</strong>g, <strong>in</strong>cludes remov<strong>in</strong>g trees<br />
27/06/2003 Site clean<strong>in</strong>g, <strong>in</strong>cludes remov<strong>in</strong>g trees<br />
28/06/2003<br />
29/06/2003<br />
30/06/2003<br />
Site clean<strong>in</strong>g, <strong>in</strong>cludes remov<strong>in</strong>g trees, demolish<strong>in</strong>g the exist<strong>in</strong>g<br />
wall<strong>in</strong>g fence, rooms and any obstructed item exist<strong>in</strong>g <strong>in</strong> the proposed<br />
area<br />
Site clean<strong>in</strong>g, <strong>in</strong>cludes remov<strong>in</strong>g trees, demolish<strong>in</strong>g the exist<strong>in</strong>g<br />
wall<strong>in</strong>g fence, rooms and any obstructed item exist<strong>in</strong>g <strong>in</strong> the proposed<br />
area and build<strong>in</strong>g eng<strong>in</strong>eer <strong>of</strong>fice<br />
Site clean<strong>in</strong>g, <strong>in</strong>cludes remov<strong>in</strong>g trees, demolish<strong>in</strong>g the exist<strong>in</strong>g<br />
wall<strong>in</strong>g fence, rooms and any obstructed item and exist<strong>in</strong>g <strong>in</strong> the<br />
proposed area and build<strong>in</strong>g eng<strong>in</strong>eer <strong>of</strong>fice<br />
01/07/2003<br />
Site clean<strong>in</strong>g, <strong>in</strong>cludes remov<strong>in</strong>g trees, demolish<strong>in</strong>g the exist<strong>in</strong>g<br />
wall<strong>in</strong>g fence, rooms and any obstructed item and exist<strong>in</strong>g <strong>in</strong> the<br />
proposed area and build<strong>in</strong>g eng<strong>in</strong>eer <strong>of</strong>fice.<br />
02/07/2003 Build<strong>in</strong>g eng<strong>in</strong>eer <strong>of</strong>fice<br />
03/07/2003 Build<strong>in</strong>g eng<strong>in</strong>eer <strong>of</strong>fice<br />
04/07/2003 Build<strong>in</strong>g eng<strong>in</strong>eer <strong>of</strong>fice<br />
05/07/2003 Build<strong>in</strong>g eng<strong>in</strong>eer <strong>of</strong>fice<br />
06/07/2003 Excavation <strong>of</strong> the natural ground to the required levels<br />
07/07/2003 Excavation <strong>of</strong> the natural ground to the required levels<br />
08/07/2003 Excavation <strong>of</strong> the natural ground to the required levels<br />
09/07/2003 Excavation <strong>of</strong> the natural ground to the required levels<br />
10/07/2003 Excavation <strong>of</strong> the natural ground to the required levels<br />
12/07/2003 Excavation <strong>of</strong> the natural ground to the required levels<br />
13/07/2003 Excavation <strong>of</strong> the natural ground to the required levels<br />
14/07/2003 Excavation <strong>of</strong> the natural ground to the required levels<br />
15/07/2003 Excavation <strong>of</strong> the natural ground to the required levels<br />
16/07/2003 Excavation <strong>of</strong> the natural ground to the required levels<br />
17/07/2003 Excavation <strong>of</strong> the natural ground to the required levels<br />
18/07/2003 Excavation <strong>of</strong> the natural ground to the required levels<br />
20/07/2003 Laboratory<br />
21/07/2003 Expand the excavation<br />
22/07/2003 Expand the excavation<br />
23/07/2003 Laboratory<br />
A1
Date<br />
24/07/2003<br />
26/07/2003<br />
27/07/2003<br />
28/07/2003<br />
29/07/2003<br />
30/07/2003<br />
31/07/2003<br />
02/08/2003<br />
03/08/2003<br />
04/08/2003<br />
05/08/2003<br />
06/08/2003<br />
07/08/2003<br />
09/08/2003<br />
10/08/2003<br />
11/08/2003<br />
12/08/2003<br />
13/08/2003<br />
14/08/2003<br />
16/08/2003<br />
17/08/2003<br />
18/08/2003<br />
19/08/2003<br />
20/08/2003<br />
21/08/2003<br />
23/08/2003<br />
24/08/2003<br />
25/08/2003<br />
26/08/2003<br />
27/08/2003<br />
28/08/2003<br />
30/08/2003<br />
31/08/2003<br />
01/09/2003<br />
02/09/2003<br />
03/09/2003<br />
Activity<br />
Cheblona work<br />
Cheblona work and Form work concrete<br />
Cheblona work and Form work concrete<br />
Cast <strong>in</strong> site 10cm thick pla<strong>in</strong> concrete (B200) for "A-B"<br />
Cast <strong>in</strong> site 10cm thick pla<strong>in</strong> concrete (B200) for "C"<br />
Form work foundation concrete "c" and steel work<br />
Form work foundation concrete "c", steel and cast 3M3 pla<strong>in</strong><br />
concrete<br />
Form work foundation concrete "c" and steel<br />
Form work foundation concrete "A-B-C"<br />
Form work foundation concrete "A-B-C "and steel<br />
Form work foundation concrete "A-B" steel work and fix neck<br />
column "A-B"<br />
Form work foundation concrete "A-B-C" and steel<br />
Fix neck column "B" and cast foundation "A-B"<br />
Remove form work part "A", form work for foundation "c-b", steel<br />
work and neck column<br />
Steel work for foundation part "B", fix steel neck column and cast<br />
foundation part<br />
Form work foundation concrete "A "and steel work.<br />
Cast ready mix concrete (B300) for re<strong>in</strong>forced concrete ground<br />
beams "B".<br />
Remove form work and steel work and clean<strong>in</strong>g<br />
Remove and re<strong>in</strong>forced concrete basement walls form work<br />
Form work neck column and wall concrete<br />
Form work neck column A-B and wall concrete and adjust <strong>of</strong> column<br />
Form work neck column A-B and wall concrete and adjust <strong>of</strong> column<br />
Form work wall concrete and cast wall concrete "A" and form work<br />
"B"<br />
Remove form work "A" neck column, form work wall concrete and<br />
neck column "B"<br />
Cast neck column "B", form work "B" wall and neck column<br />
Form work neck column "A,B" and remove form work wall<br />
Form work part "B-C" and cast neck column part B<br />
Cast A-C<br />
Remove form work and clean<strong>in</strong>g foundation.<br />
Isolation work and Clean<strong>in</strong>g site<br />
Form work for wall and neck column part "c", isolation work and<br />
Clean<strong>in</strong>g site<br />
Form work for wall and neck column , isolation work and clean<strong>in</strong>g<br />
site<br />
Isolation work and clean<strong>in</strong>g site<br />
Back fill<strong>in</strong>g and clean<strong>in</strong>g site<br />
Back fill<strong>in</strong>g , laboratory and clean<strong>in</strong>g site<br />
Back fill<strong>in</strong>g 25cm , laboratory and clean<strong>in</strong>g site<br />
A2
04/09/2003<br />
06/09/2003<br />
07/09/2003<br />
08/09/2003<br />
09/09/2003<br />
10/09/2003<br />
11/09/2003<br />
13/09/2003<br />
14/09/2003<br />
15/09/2003<br />
16/09/2003<br />
17/09/2003<br />
18/09/2003<br />
20/09/2003<br />
21/09/2003<br />
22/09/2003<br />
23/09/2003<br />
24/09/2003<br />
25/09/2003<br />
26/09/2003<br />
27/09/2003<br />
28/09/2003<br />
29/09/2003<br />
30/09/2003<br />
01/10/2003<br />
02/10/2003<br />
04/10/2003<br />
08/10/2003<br />
09/10/2003<br />
11/10/2003<br />
12/10/2003<br />
13/10/2003<br />
14/10/2003<br />
15/10/2003<br />
16/10/2003<br />
18/10/2003<br />
19/10/2003<br />
20/10/2003<br />
21/10/2003<br />
22/10/2003<br />
23/10/2003<br />
25/10/2003<br />
26/10/2003<br />
27/10/2003<br />
Back fill<strong>in</strong>g 25 cm , laboratory and clean<strong>in</strong>g site<br />
Form work for 5 foundation part "c", back fill<strong>in</strong>g work and steel work<br />
Form work for 5 foundation, back fill<strong>in</strong>g second layer25 cm<br />
Form work for 5 foundation part "c", back fill<strong>in</strong>g , steel work and<br />
laboratory<br />
Back fill<strong>in</strong>g 25 cm<br />
Form work for wall part "c" and Back fill<strong>in</strong>g 25 cm<br />
Form work for wall, neck column part "c" and back fill<strong>in</strong>g 25 cm<br />
Form work neck column part "c" and back fill<strong>in</strong>g part "A-B"<br />
Cast neck column part "c" and back fill<strong>in</strong>g<br />
Remove form work neck column and Back fill<strong>in</strong>g<br />
Back fill<strong>in</strong>g work 25 cm<br />
Back fill<strong>in</strong>g work 25 cm, form work for ground beam and isolation<br />
work<br />
Back fill<strong>in</strong>g work 25 cm and form work for ground beam<br />
Form work for ground beam "A-B-C"<br />
Form work for ground beam "A-B-C"<br />
Form work for ground beam " B "<br />
Form work for ground beam " B "<br />
Form work for ground beam " B "<br />
Form work for ground beam " B "<br />
Form work for ground beam " B "<br />
Form work for ground beam " B "<br />
Form work for ground beam "A-B-C"<br />
Steel work , excavation under ground beam part "B"<br />
Steel work "A-B"<br />
Form work ground beam "A-C", steel work for part "B", Supply,<br />
<strong>in</strong>stall and test UPVC and earth electric..<br />
form work for ground beam "A-B-C" , sanitary work and earth<br />
electric<br />
Form work ground beam "B" and earth electric<br />
Caste ground part "C"<br />
Caste ground part "A"<br />
Remove form work "A", Form work wall and column "c"<br />
Remove form work "A", Form work wall and column "c", steel work<br />
ground beam "c"<br />
Form work G. beam, Form work column "c" and mechanical work<br />
Form work G.beam , Wall "B", Steel work "c", Isolation work<br />
Form work G. beam, Steel work column, isolation work<br />
Form work wall , Column" ABC"<br />
Form work wall and Column "ABC"<br />
Cast G. Beam "B", form work wall and column "AC"<br />
Remove form wall"B",Form work "AC"<br />
Remove form wall"B"and form work "AC"<br />
Remove form wall"B"and form work "AC"<br />
Form work "ABC"<br />
Form work "ABC"<br />
F<strong>in</strong>ish<strong>in</strong>g work and isolation<br />
Isolation work and clean<strong>in</strong>g<br />
A3
28/10/2003<br />
30/10/2003<br />
01/11/2003<br />
02/11/2003<br />
03/11/2003<br />
04/11/2003<br />
05/11/2003<br />
06/11/2003<br />
08/11/2003<br />
09/11/2003<br />
10/11/2003<br />
11/11/2003<br />
12/11/2003<br />
13/11/2003<br />
15/11/2003<br />
16/11/2003<br />
17/11/2003<br />
18/11/2003<br />
19/11/2003<br />
20/11/2003<br />
22/11/2003<br />
23/11/2003<br />
24/11/2003<br />
29/11/2003<br />
30/11/2003<br />
01/12/2003<br />
04/12/2003<br />
07/12/2003<br />
08/12/2003<br />
09/12/2003<br />
10/12/2003<br />
11/12/2003<br />
13/12/2003<br />
14/12/2003<br />
15/12/2003<br />
16/12/2003<br />
17/12/2003<br />
Form work wall "c" and column "B"<br />
Column and wall "c" and manhole work "B"<br />
Cast column and wall "c" and manhole work "B" and clean<strong>in</strong>g work<br />
Manhole work "BC" and remove form work "C"<br />
Manhole work "BC" and remove form work "C"<br />
Back fill<strong>in</strong>g between ground beam and mechanic work and steel<br />
work" wall B"<br />
Back fill<strong>in</strong>g between ground beam and Form work "B" and<br />
Mechanical work<br />
Back fill<strong>in</strong>g and mechanic work<br />
Back fill<strong>in</strong>g and mechanic work and steel work for column A"<br />
Steel work and Mechanic work and Column and wall "B"<br />
Column and wall 'AB" and Mechanic work<br />
Column and wall 'AB" and Mechanic work<br />
Column and wall 'AB" and Mechanic work and ground floor steel<br />
work<br />
Cast "A" Column and wall and steel ground floor "AB" and<br />
formwork wall and column and mechanical work<br />
Remove form work "A" column and wall and Ground floor "B" and<br />
Form work wall and column "B" and Mechanical work<br />
Cast "c" ground floor and Form work column "<br />
B" remove form work wall and column "A"<br />
Form work column "B”, ground floor work "B" and remove form<br />
work column "A"<br />
Form work column, ground floor AB and Mechanical work and<br />
ground floor slab form work<br />
Form work column "B", ground floor work AB and mechanical work<br />
and Slab form work "c"<br />
Cast ground floor " AB" and Form work column "B" and Form work<br />
slab "c"<br />
Cast column "c", electric work "b", slab work "c" and Ground floor<br />
"B"<br />
Column "B", slab "c" and Ground floor "B"<br />
Cast column "B" and Remove 7 column and Ground floor work<br />
Steel wall and column , slab work "c" and ground floor "B"<br />
Slab "c 'and Wall "B"<br />
Cast ground floor 550m2 "B', slab "c" and wall work "B"<br />
Cast wall "B"<br />
Remove form work band steel work slab "c" and form work "A" slab<br />
Remove form work for wall "B", slab "CA "and column work "B"<br />
Cast column "B", Slab steel, mechanic work "CA" and Remove form<br />
work wall "B".<br />
Slab "AC"<br />
Slab Work "AC" and Cast column "A"<br />
Slab work "AC"<br />
Slab work "AC"<br />
Slab work "AC"<br />
Cast slab "c"and Slab work "AC"and Wall work<br />
Slab work "A"and Column work "c"<br />
A4
18/12/2003<br />
20/12/2003<br />
21/12/2003<br />
22/12/2003<br />
23/12/2003<br />
24/12/2003<br />
25/12/2003<br />
27/12/2003<br />
29/12/2003<br />
30/12/2003<br />
31/12/2003<br />
01/01/2004<br />
03/01/2004<br />
04/01/2004<br />
06/01/2004<br />
11/01/2004<br />
12/01/2004<br />
13/01/2004<br />
14/01/2004<br />
15/01/2004<br />
17/01/2004<br />
18/01/2004<br />
19/01/2004<br />
20/01/2004<br />
21/01/2004<br />
22/01/2004<br />
24/01/2004<br />
25/01/2004<br />
26/01/2004<br />
27/01/2004<br />
28/01/2004<br />
29/01/2004<br />
05/02/2004<br />
07/02/2004<br />
08/02/2004<br />
09/02/2004<br />
10/02/2004<br />
11/02/2004<br />
12/02/2004<br />
16/02/2004<br />
17/02/2004<br />
18/02/2004<br />
19/02/2004<br />
21/02/2004<br />
22/02/2004<br />
23/02/2004<br />
24/02/2004<br />
25/02/2004<br />
Slab work "A"and Column work "c"<br />
Slab work "AB"and Column work "c"<br />
Slab work "AB"<br />
Slab work "AB" and Column work "c"<br />
Slab work "AB" and Column work "c"<br />
Slab work "AB" and Column work "c"<br />
Slab work "AB" and Column work "c"<br />
Cast column "c" and slab "AB"<br />
Slab work "AB"<br />
Cast slab "A" and Work <strong>in</strong> slab "B"<br />
Slab electric work "B"<br />
Slab work "B"<br />
Slab work "B"<br />
Cast Slab work "B"1670m2andform work second floor slab "c"<br />
Form work second floor slab "c" and Column axes "AB"<br />
Form work second floor slab "c" and Column "AB"<br />
Form work second floor slab "c" and Column "AB"<br />
Form work second floor slab "c" and Column "AB"<br />
Form work second floor slab "c" and Column "AB"<br />
Form work second floor slab "c" and Column "AB"<br />
Form work second floor slab "c" and Column "AB"<br />
Column work "AB"<br />
Form work second floor slab "c", column "AB" and Cast column "A"<br />
Form work second floor slab "AC" and Column "B"<br />
Cast slab "c" and Cast 16 column <strong>in</strong> part "B"<br />
Work slab " AB' and Work column "B" and<br />
Work slab " AB and Work column "B" and electric work<br />
Slab "AB" and Electric slab "A" and column "B"<br />
Cast column "B" and Slab work AB<br />
Remove form work" B" and slab A B<br />
Cast slab "A" and Work <strong>in</strong> slab "B".<br />
Work <strong>in</strong> slab "B"<br />
Work <strong>in</strong> slab "B"<br />
Slab "B" and Column "AC<br />
Slab "B" and Column "AC"<br />
Cast column "C" and slab eclectic "B" and column "A"<br />
Slab "c", clean<strong>in</strong>g, first floor column A and Slab B<br />
Slab "c", build<strong>in</strong>g work and first floor column A and Slab B<br />
Slab "c" and build<strong>in</strong>g work and First floor column A and Slab B<br />
Cast column "A" and Build<strong>in</strong>g work and F<strong>in</strong>ish<strong>in</strong>g work <strong>in</strong> slab "B"<br />
Slab "c" and Cast slab "B" and build<strong>in</strong>g work<br />
Slab A C and Build<strong>in</strong>g work<br />
Slab A C and Build<strong>in</strong>g work<br />
Slab A, electric slab C and Build<strong>in</strong>g work<br />
Slab A and Electric slab C and L<strong>in</strong>tel work<br />
Slab A C and Build<strong>in</strong>g work<br />
Slab A C and Build<strong>in</strong>g work<br />
Slab A C and Build<strong>in</strong>g work and Column "B"<br />
A5
26/02/2004 Slab A C and Build<strong>in</strong>g work and Column "B"<br />
27/02/2004 Cast slab "C' and Slab work A and Build<strong>in</strong>g work<br />
29/2/2003 Slab A and Build<strong>in</strong>g work and Column "B"<br />
Stop work because there are Conflict between the contractor and the<br />
01/03/2004 consultant.<br />
02/03/2004<br />
Stop work because there are Conflict between the contractor and the<br />
consultant.<br />
03/03/2004 Slab A and Build<strong>in</strong>g work AC and electric work <strong>in</strong> wall<br />
04/03/2004 Slab A and Build<strong>in</strong>g work AC and electric work <strong>in</strong> wall<br />
06/03/2004 Slab A and Build<strong>in</strong>g work and Column "B"<br />
07/03/2004 Slab A and Build<strong>in</strong>g work and Column "B"<br />
08/03/2004 Slab A and Build<strong>in</strong>g work and Column "B" and l<strong>in</strong>tel work<br />
09/03/2004 Slab A and Build<strong>in</strong>g work and Column "B"<br />
10/03/2004 Slab A and F<strong>in</strong>ish<strong>in</strong>g Build<strong>in</strong>g work and Column "B"<br />
11/03/2004 Cast column ground floor "B" and Slab electric "A" and L<strong>in</strong>tel AC<br />
13/03/2004 Build<strong>in</strong>g ground floor BC and L<strong>in</strong>tel A and Column first floor "B"<br />
Cast column ground floor "B" and check slab "A" and L<strong>in</strong>tel A and<br />
15/03/2004 Build<strong>in</strong>g ground floor "B"<br />
16/03/2004<br />
Cast first slab "B" and cast l<strong>in</strong>tel" A" and Build<strong>in</strong>g "B" and Electric<br />
work and Slab first floor "B'<br />
17/03/2004<br />
Column first floor "B" and Slab first floor AB and build<strong>in</strong>g work and<br />
Electric wall<br />
18/03/2004<br />
Cast column first floor "B" and slab work "B' and L<strong>in</strong>tel ground floor<br />
"A" and Electric wall and Slab "A" and Back fill<strong>in</strong>g column<br />
20/03/2004<br />
Remove form work for column "B" and slab first floor "BC" and<br />
Build<strong>in</strong>g<br />
26/03/2003<br />
Build<strong>in</strong>g ground floor "B" and l<strong>in</strong>tel and slab first floor "B" and Form<br />
work7 column "B"<br />
27/03/2004 Build<strong>in</strong>g ground floor "AB" and cast "B" and slab first floor "B"<br />
28/03/2004 Build<strong>in</strong>g ground floor "B" and slab first floor "B"<br />
29/03/2004 Build<strong>in</strong>g ground floor "B" and slab first floor "B"<br />
30/03/2004<br />
Build<strong>in</strong>g ground floor "ACB and Slab first floor "B" and l<strong>in</strong>tel<br />
ground floor "B"<br />
31/03/2004<br />
Slab first floor "B" and Build<strong>in</strong>g first floor "c" and L<strong>in</strong>tel ground<br />
floor "B"<br />
01/04/2004 Slab first floor "B" and build<strong>in</strong>g AC and l<strong>in</strong>tel "B"<br />
02/04/2004 Slab first floor "B" and Build<strong>in</strong>g first floor "C"<br />
04/04/2004 Slab first floor "B" and L<strong>in</strong>tel ground floor "B'<br />
05/04/2004<br />
Slab first floor "B" and l<strong>in</strong>tel ground floor "B and build<strong>in</strong>g first floor<br />
"A"<br />
06/04/2004<br />
Slab first floor "B" and l<strong>in</strong>tel ground floor "B and build<strong>in</strong>g first floor<br />
"B"<br />
07/04/2004<br />
Slab first floor "B" and l<strong>in</strong>tel ground floor "B and build<strong>in</strong>g first floor<br />
"A"<br />
08/04/2004<br />
Cast l<strong>in</strong>tel "B" and l<strong>in</strong>tel ground floor "C" and build<strong>in</strong>g up l<strong>in</strong>tel "B"<br />
and slab first floor "B"<br />
Cast l<strong>in</strong>tel "B" and l<strong>in</strong>tel ground floor "C" and build<strong>in</strong>g up l<strong>in</strong>tel "B"<br />
10/04/2004 and s lab first floor "B" and electric floor "B" and electric ground<br />
floor "A"<br />
A6
11/04/2004<br />
12/04/2004<br />
13/04/2004<br />
14/04/2004<br />
15/04/2004<br />
17/04/2004<br />
18/04/2004<br />
19/04/2004<br />
20/04/2004<br />
21/04/2004<br />
22/04/2004<br />
24/04/2004<br />
25/04/2004<br />
26/04/2004<br />
27/04/2004<br />
28/04/2004<br />
29/04/2004<br />
01/05/2004<br />
02/05/2004<br />
03/05/2004<br />
04/05/2004<br />
05/05/2004<br />
06/05/2004<br />
08/05/2004<br />
09/05/2004<br />
10/05/2004<br />
11/05/2004<br />
12/05/2004<br />
13/05/2004<br />
15/05/2004<br />
16/05/2004<br />
17/05/2004<br />
18/05/2004<br />
19/05/2004<br />
26/05/2004<br />
29/05/2004<br />
21/06/2004<br />
07/07/2004<br />
08/07/2004<br />
09/07/2004<br />
11/03/2004<br />
Cast l<strong>in</strong>tel "BC" and Slab first floor "B"<br />
Slab first floor "B" and l<strong>in</strong>tel AB<br />
Slab first floor "B"<br />
Column first floor27"B"andBuid<strong>in</strong>g "B" and l<strong>in</strong>tel Ground floor A<br />
Slab floor "B" and Build<strong>in</strong>g up l<strong>in</strong>tel "B"<br />
Cast l<strong>in</strong>tel ground floor "B" and Electric slab work and Build<strong>in</strong>g<br />
ground floor "B"<br />
Remove form work for l<strong>in</strong>tel and Electric work<br />
Remove form work for l<strong>in</strong>tel and Electric work and slab floor "B"<br />
Slab first floor "B" and L<strong>in</strong>tel Ground floor BC<br />
Slab first floor "B" and L<strong>in</strong>tel Ground floor ABC and build<strong>in</strong>g "B"<br />
Cast Slab first floor "B" and L<strong>in</strong>tel Ground floor ABC and build<strong>in</strong>g<br />
"B"<br />
Plaster<strong>in</strong>g work and Start remove form work for slab first floor and<br />
Electric work and L<strong>in</strong>tel AC<br />
Plster<strong>in</strong>g and L<strong>in</strong>tel floor "AC" and electric ground floor.<br />
Plaster<strong>in</strong>g and Form work G.Floor" and Electric ground floor<br />
Column ro<strong>of</strong> and Plaster<strong>in</strong>g work.<br />
Form work l<strong>in</strong>tel ground floor and column ro<strong>of</strong> and Plaster<strong>in</strong>g and<br />
electric ground floor<br />
Form work l<strong>in</strong>tel ground floor and column ro<strong>of</strong> and Plaster<strong>in</strong>g and<br />
Electric G.F.<br />
Column ro<strong>of</strong> and Plaster<strong>in</strong>g and Electric G.F.<br />
Column ro<strong>of</strong> and Plaster<strong>in</strong>g and Electric G.F.<br />
Plaster<strong>in</strong>g work<br />
Stop work because <strong>of</strong> a conflict between the contractor and<br />
consultant<br />
Stop work because <strong>of</strong> a conflict between the contractor and<br />
consultant<br />
Stop work because <strong>of</strong> a conflict between the contractor and<br />
consultant<br />
Remove slab "B" and open w<strong>in</strong>dow <strong>in</strong> wall and Form work<br />
Remove slab "B" and Open w<strong>in</strong>dow <strong>in</strong> wall and Electric work<br />
Plaster<strong>in</strong>g work and L<strong>in</strong>tel and Remove form work slab<br />
Ro<strong>of</strong> slab and build<strong>in</strong>g work<br />
Ro<strong>of</strong> slab and Plaster<strong>in</strong>g work<br />
Stop work because there are defect <strong>in</strong> works.<br />
Slab work and Build<strong>in</strong>g work and plaster<strong>in</strong>g<br />
Slab work and Open w<strong>in</strong>dow <strong>in</strong> wall and Plaster<strong>in</strong>g<br />
Column ro<strong>of</strong> and Plaster<strong>in</strong>g<br />
Cast column ro<strong>of</strong><br />
Remove form work column ro<strong>of</strong><br />
Build<strong>in</strong>g work<br />
Open w<strong>in</strong>dow <strong>in</strong> wall<br />
Electric wall<br />
Slab ro<strong>of</strong> and Build<strong>in</strong>g ro<strong>of</strong> <strong>in</strong> first floor<br />
Build<strong>in</strong>g <strong>in</strong> first floor and Stop work <strong>in</strong> ro<strong>of</strong> slab<br />
Cast ro<strong>of</strong> slab<br />
Build<strong>in</strong>g first floor<br />
A7
12/07/2004 Build<strong>in</strong>g first floor<br />
13/07/2004 Build<strong>in</strong>g first floor<br />
14/07/2004 Build<strong>in</strong>g first floor<br />
15/07/2004 Build<strong>in</strong>g first floor<br />
17/03/2004 Slab ro<strong>of</strong><br />
18/07/2004 Build<strong>in</strong>g first floor "B" and slab ro<strong>of</strong><br />
19/07/2004 Form work l<strong>in</strong>tel first floor "B"<br />
20/07/2004 Slab ro<strong>of</strong><br />
21/07/2004 Slab ro<strong>of</strong><br />
22/011/2004 Build<strong>in</strong>g first floor "BC"<br />
24/07/2005 Form work ro<strong>of</strong> slab and build<strong>in</strong>g work<br />
25/07/2005 Cast l<strong>in</strong>tel first floor and electric ro<strong>of</strong> slab work<br />
26/07/2005 Slab ro<strong>of</strong><br />
31/07/2005 L<strong>in</strong>tel first floor and build<strong>in</strong>g first floor<br />
01/08/2005 Slab ro<strong>of</strong> and l<strong>in</strong>tel first floor<br />
02/08/2005 F<strong>in</strong>ish<strong>in</strong>g slab ro<strong>of</strong> and form work l<strong>in</strong>tel <strong>in</strong> first floor<br />
03/08/2005 Build<strong>in</strong>g first floor and electric slab ro<strong>of</strong> and l<strong>in</strong>tel first floor<br />
04/08/2005 Slab ro<strong>of</strong> and l<strong>in</strong>tel first floor<br />
05/08/2005 Slab ro<strong>of</strong> and l<strong>in</strong>tel first floor<br />
07/08/2005 Slab ro<strong>of</strong> and build<strong>in</strong>g first floor<br />
08/08/2005 Slab ro<strong>of</strong><br />
09/08/2005 L<strong>in</strong>tel first floor cast slab ro<strong>of</strong>.<br />
10/08/2005 Build<strong>in</strong>g first floor and l<strong>in</strong>tel first floor<br />
11/08/2005 Build<strong>in</strong>g first floor and l<strong>in</strong>tel first floor<br />
12/08/2005 Build<strong>in</strong>g first floor and l<strong>in</strong>tel first floor<br />
0412/2005 Build<strong>in</strong>g work<br />
A8
Appendix (B)<br />
Arena Simulation<br />
Computer simulation is def<strong>in</strong>ed by Pristker (1986) as the process <strong>of</strong> design<strong>in</strong>g a<br />
mathematical-logical model <strong>of</strong> a real world system and experiment<strong>in</strong>g with the model<br />
on a computer. Simulation has proved to be a valuable analytical tool <strong>in</strong> many fields.<br />
Particularly, it is powerful when study<strong>in</strong>g resource-driven processes s<strong>in</strong>ce it provides a<br />
Fast and economical way to experiment with different alternatives and approaches.<br />
Furthermore, key factors <strong>in</strong> the process can be identified through an <strong>in</strong>-depth<br />
understand<strong>in</strong>g <strong>of</strong> the <strong>in</strong>teractions <strong>of</strong> resources and processes. <strong>Construction</strong> operations<br />
<strong>in</strong>clude many processes. The flow between processes and the resource utilization at<br />
every step thus determ<strong>in</strong>es the performance <strong>of</strong> the whole project. To understand the<br />
<strong>in</strong>teraction <strong>of</strong> construction processes and the impact <strong>of</strong> resource supply, the construction<br />
project planner can experiment with different comb<strong>in</strong>ations <strong>of</strong> construction processes<br />
and vary<strong>in</strong>g levels <strong>of</strong> resource supply <strong>in</strong> a simulation environment to seek the best<br />
performance for their construction operation.<br />
Arena s<strong>of</strong>tware (Rockwell S<strong>of</strong>tware Manual, 2000) is used to simulate and represent the<br />
real system which allows the planners to observe the behavior <strong>of</strong> the system when<br />
changes are made <strong>in</strong> the system. Also Arena enables the planners to br<strong>in</strong>g the power <strong>of</strong><br />
model<strong>in</strong>g and simulation to their plann<strong>in</strong>g.<br />
Objectives <strong>of</strong> arena are:<br />
1. It has good ability for the <strong>in</strong>terface.<br />
2. It has good ability to build scenarios.<br />
3. Data entry is easy.<br />
4. Output reports are more comprehensive.<br />
5. It has good animation for the real system.<br />
The follow<strong>in</strong>g table show the basic elements <strong>of</strong> arena simulation.<br />
B1
Table B1: The basic elements <strong>of</strong> arena simulation<br />
No. Name Symbol<br />
1. Create Module<br />
2. Process Module<br />
3. Decide Module<br />
4. Assign Module<br />
5. Batch Module<br />
6.<br />
7.<br />
8.<br />
Separate Module<br />
Record Module<br />
Dispose Module<br />
B2<br />
Description<br />
Start<strong>in</strong>g po<strong>in</strong>t for entities <strong>in</strong> a<br />
Simulation model<br />
The ma<strong>in</strong> process<strong>in</strong>g method <strong>in</strong> the<br />
simulation<br />
Decision-Mak<strong>in</strong>g processes <strong>in</strong> the<br />
system<br />
Assign<strong>in</strong>g new values to variables<br />
The group<strong>in</strong>g mechanism with<strong>in</strong><br />
the simulation model.<br />
Split a previously batches entity.<br />
Collect statistics <strong>in</strong> the simulation<br />
model.<br />
End<strong>in</strong>g po<strong>in</strong>t for entities <strong>in</strong> a<br />
simulation model.
Appendix (C )<br />
Simulation result <strong>of</strong> the project before apply<strong>in</strong>g eight po<strong>in</strong>ts and after<br />
apply<strong>in</strong>g lean tools<br />
C1
Non value added time processes<br />
D4