A Study of Lean Construction Practices in Gaza Strip

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the work flow, material flow, productivity, and the relationship among team members. Ballard and Howell (2003) indicates that WWP should emphasize the learning process more by investigating the causes of delays on the WWP instead of assigning blames and only focusing on PPC values. Variance analysis is conducted based on the work performance plan from the previous week. The causes of variance should be documented within the WWP schedule (Figure 2.2) CAN SHOULD LAST PLANNER PLANNING Figure 2.2 Last Planner planning WILL 2.6.2. 5 Percent Plan Complete (PPC) The measurement metric of Last Planner is the Percent Plan Complete (PPC) values. It is calculated as the number of activities that are completed as planned divided by the total number of planned activities (Ballard 2000). The positive (upward) slope between two PPC values means that production planning was reliable and vice versa. According to Ballard (1999), PPC values are highly variable and usually range from 30% to 70% without lean implementation. To achieve higher values (70% and above), additional lean construction tools such as first run studies have to be implemented. 2.6.3 Increased Visualization The increased visualization lean tool is about communicating key information effectively to the workforce through posting various signs and labels around the construction site. Workers can remember elements such as workflow, performance targets, and specific required actions if they visualize them (Moser and Dos Santos 2003). This includes signs related to safety, schedule, and quality. This tool is similar to 18
the lean manufacturing tool, Visual Controls, which is a continuous improvement activity that relates to the process control 2.6.4 First Run Studies First Run Studies are used to redesign critical assignments (Ballard and Howell et al., 1977), part of continuous improvement effort; and include productivity studies and review work methods by redesigning and streamlining the different functions involved. The studies commonly use video files, photos, or graphics to show the process or illustrate the work instruction. The first run of a selected craft operation should be examined in detail, bringing ideas and suggestions to explore alternative ways of doing the work. A PDCA cycle (plan, do, check, act) is suggested to develop the study: Plan refers to select work process to study, assemble people, analyze process steps, brainstorm how to eliminate steps, check for safety, quality and productivity. Do means to try out ideas on the first run. Check is to describe and measure what actually happens. Act refers to reconvening the team, and communicating the improved method and performance as the standard to meet. 2.6.5 Daily Huddle Meetings (Tool-box Meetings) Two-way communication is the key of the daily huddle meeting process in order to achieve employee involvement. With awareness of the project and problem solving involvement along with some training that is provided by other tools, employee satisfaction (job meaningfulness, self-esteem, sense of growth) will increase. As part of the improvement cycle, a brief daily start-up meeting was conducted where team members quickly give the status of what they had been working on since the previous day's meeting, especially if an issue might prevent the completion of an assignment (Schwaber, 1995). This tool is similar to the lean manufacturing concept of employee involvement, which ensures rapid response to problems through empowerment of workers, and continuous open communication through the tool box meetings. 2.6.6 The 5s Process (Visual Work Place) • Sort The first level of housekeeping consisted of separating material by reference and placing materials and tools close to the work areas with consideration of safety and crane movements. 19
Page 1: The Islamic University of Gaza Dean
Page 4 and 5: Acknowledgment I would like to expr
Page 6 and 7: ABSTRACT This research deals with t
Page 8 and 9: 2.5.6 Increase Output Flexibility .
Page 10 and 11: Appendices Appendix (A): Daily Repo
Page 12 and 13: List of Tables Table 2.1: Conceptua
Page 14 and 15: List of Figures Figure 2.1: Reducti
Page 16 and 17: 1.1 Statement of the Problem Most o
Page 18 and 19: 2.1 Lean Construction History Chapt
Page 20 and 21: 2.3 Impact of Lean Construction Acc
Page 22 and 23: Table 2.1 Conceptualization of lean
Page 24 and 25: for measuring the percent plan comp
Page 26 and 27: 2.5.6 Increase output flexibility F
Page 28 and 29: � The more wastes inherent in the
Page 30 and 31: 3. System requires the need to deve
Page 34 and 35: • Straighten Next, materials were
Page 36 and 37: Material Productivity = Total Outpu
Page 38 and 39: investigation showed that 25 percen
Page 40 and 41: 7. Poor technology of equipment. 8.
Page 42 and 43: 2. Unnecessary material handling. 3
Page 44 and 45: inventory (Wrong storage of materia
Page 46 and 47: Main Activity Mobilization and exca
Page 48 and 49: 4. Sort the candidates in order of
Page 50 and 51: 4.2 Project Activities Lean constru
Page 52 and 53: Table 4.2 represents the resources,
Page 54 and 55: Main Activity Slab work Building wo
Page 56 and 57: 4.4.1 Mobilization and excavation T
Page 58 and 59: 4.4.4 Neck column Table (4.6) shows
Page 60 and 61: 4.4.7 Ground beam The twelve proces
Page 62 and 63: 4.4.10 Ground floor slab The eleven
Page 64 and 65: No. 9 10 11 Table 4.14 Non-value ad
Page 66 and 67: 4.5 Remove or Reduce the Influence
Page 68 and 69: The result by using arena simulatio
Page 70 and 71: Table 4.17 Simulation results No. A
Page 72 and 73: Table 4.17 Simulation results (Cont
Page 74 and 75: 4.5.3 Foundation Table (4.20) shows
Page 76 and 77: 4.5.7 Ground beam Table (4.24) show
Page 78 and 79: 4.5.11 Column first floor Table (4.
Page 80 and 81: 4.6 Identify the Cause of Waste Tab
Page 82 and 83:
Percent of value adding time 35% 30
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Table 4.33 Total project duration N
Page 86 and 87:
Then, the processes with the greate
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number of workers to 12 workers sho
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Activity Process Ground floor Colum
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Actual project duration was 6000 ho
Page 94 and 95:
Date Process Assigned Process Compl
Page 96 and 97:
5.1 Conclusion Chapter Five Conclus
Page 98 and 99:
References 1. Abudallah Fawaz , (20
Page 100 and 101:
27. Graham, P. and Smithers, G., (1
Page 102 and 103:
51. Serpell, A.; Venturi, A. and Co
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Appendices (A) Daily report Date Ac
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04/09/2003 06/09/2003 07/09/2003 08
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18/12/2003 20/12/2003 21/12/2003 22
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11/04/2004 12/04/2004 13/04/2004 14
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Appendix (B) Arena Simulation Compu
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Appendix (C ) Simulation result of
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