Civil Engineering Project Management (4th Edition)

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Percussion drilling Site surveys, investigations and layout 135 A percussion drill may be used to penetrate rock or boulders if no cores are required. A percussion chisel, usually of cruciform shape with a string of tools to give it weight, all suspended on a wire rope, is raised and let fall repeatedly on the rock base of the hole. The chisel has to be let fall with a clean blow on the base, and it is caused to rotate a little with each blow by the suspension wire having a left hand lay, and a friction grip attachment which lets the wire re-set from time to time. The drill chisel must be sharpened regularly. The rock chips are removed by water flush in small holes; in larger holes a bailer, very similar to a shell, has to be lowered at intervals to collect the chippings. Sometimes it is only necessary to find the depth at which hard material, such as rock exists, or to drill sufficiently far into rock to ensure it is not a boulder overlying soft material below. In such situations a down-the-hole hammer drill can be used at a relatively small diameter. The blows to the cruciform bit are applied by a compressed-air operated hammer adjacent to the bit. The rock fragments are either blown out to the surface, or washed out by drilling water supplied through waterways inside the drill rods and can be examined. Small percussion drills of this type, 50–75 mm size, are fast and can penetrate something of the order of 6 m of rock or concrete per hour. 12.9 Other means of ground investigation The hydraulic digger (or backhoe) is useful as a means of revealing the nature and extent of shallow overburden material on site. It can excavate a trench up to 3–4 m deep in soft or moderately hard material, at a fast rate and cheaply. The substantial cross-section of material then revealed for inspection can be more informative than samples from a few borings. However, trenches of this depth must be securely supported before access for inspection is allowable. A sampling tube can sometimes be pushed into the base of the trench using the digger bucket, and then dug out by the same machine. The auger may be used for boring holes in soft materials. A lining may be required to keep a hole open during and after boring. Large augers, machine driven, are used for sinking shafts for the formation of in situ concreted piles. For site investigations, the hand-auger is a simple little tool, usually of 75–150 mm diameter, for penetrating shallow depths of soft material. About 300 mm of material is penetrated at a time before the tool is withdrawn and the material taken out of it and examined. Two men are usually required to twist the auger, the hole being watered from time to time if necessary in order to reduce friction. Penetration is usually of the order of 1.5–2.5 m; to get a hole deeper than 3 m the ground has to be very soft. Gravel or cobbles cannot be penetrated. The tool is useful for locating the extent and depth of shallow, very soft overburden material.
136 Civil Engineering Project Management As an alternative to rotary core drilling the same rig can be used for open hole drilling where the drill bit cuts all material within the hole. Casing may be needed in unstable ground. This can be a rapid means of reaching a required depth to carry out a test or install instruments. 12.10 Judging the safe bearing value of a foundation The safe bearing value for a given foundation material ought not to be decided by the resident engineer but by the engineer or his specialist advisers. However, the engineer will not thank the resident engineer for referring to him questions about foundation materials which are obviously satisfactory, such as gravel and rock, where the load thereon is well within the traditionally accepted bearing strength. Standard field descriptions are given in BS 5930 for various materials and BS 8004, Table 1 shows allowable bearing values for such materials for preliminary design purposes. In clays or silts, or materials having clay bands or organic layers, and other mixtures containing weak layers, special investigations, sampling techniques and sophisticated analyses may be necessary before a safe bearing value can be advised – dependent upon the type of structure the formation is to support. These matters need to be considered by an experienced geotechnical engineer. Site tests, such as the ‘standard penetration test’, vane shear tests and permeability tests, may be used but these must be regarded as an adjunct only to more sophisticated investigation techniques. Details of the standard penetration test are given in BS 1377 Part 9: 1990, para 3.3. Its widest use on site is to reveal any weak spots in an otherwise consistent foundation material. 12.11 Testing apparatus for a site soils laboratory The usual apparatus suitable for a small soils laboratory on site, to be run by the resident engineer’s staff after proper instruction from a geotechnical engineer, is set out below. For moisture content determinations 1. Beam balance weighing by 0.01 g divisions. 2. Drying oven, thermostatically controlled. (Not absolutely essential. For rough measurement of moisture content the sample can be dried on a flat tray over a stove.) 3. Six drying trays.
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Civil Engineering Project Managemen
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Civil Engineering Project Managemen
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Contents Preface xiii Acknowledgeme
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Contents vii 4.3 Conditions publish
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Contents ix 10.3 The Health and Saf
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Contents xi 15.4 Problems with clas
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Preface Most civil engineering cons
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1 The development of construction p
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The great majority of all civil eng
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and takes over ownership of them at
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The development of construction pro
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supported by the DETR’s 7 Constru
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advantage is that a contractor who
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civil engineering, incorrect or ins
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The development of construction pro
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2 Procedures for design and constru
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2.3 Options for design The followin
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utilities in the UK continued to us
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Some plant suppliers, however, will
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• The promoter may need to employ
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given period of a year or longer. T
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3 Payment arrangements, risks and p
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(c) Lump sum contracts Payment arra
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inflation of prices after he has te
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Payment arrangements, risks and pro
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Payment arrangements, risks and pro
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if not, to make some deletion to re
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Contract conditions used for civil
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D&C contracts are often used when t
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4.3 Conditions published by the Int
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authorities. A range of standard fo
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Contract conditions used for civil
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5.2 Roles of the key participants i
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Preparing contract documents 53 the
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Preparing contract documents 55 mat
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work. Some methods may need to be s
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personnel may also be included. Thi
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Preparing contract documents 61 hen
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Preparing contract documents 63 ‘
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invited to bid for the project. Con
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Tendering 67 If pre-qualification i
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construction, so that they can plan
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e avoided because they can provide
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corrected. Where this results in an
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6.8 Choosing a tender Tendering 75
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Tendering 77 • an intent that the
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Appendix: UK Regulations UK Statuto
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execution of the contract, but he d
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of formwork carpenters, steel erect
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Page 104 and 105: 8.1 Introduction 8 The employer and
Page 106 and 107: 8.3 A note on alternative provision
Page 108 and 109: further drawings the contractor nee
Page 110 and 111: (see References 5 and 6). But under
Page 112 and 113: The resident engineer’s duties 97
Page 116 and 117: need to go carefully at first so th
Page 122 and 123: 10 Health and safety regulations 10
Page 124 and 125: Health and safety regulations 109 N
Page 126 and 127: 10.5 Training As part of the drive
Page 128 and 129: should be evaluated. This is a new
Page 130 and 131: 10.9 The Construction (Health, Safe
Page 132 and 133: Health and safety regulations 117 C
Page 134 and 135: enable first aid to be given to emp
Page 136 and 137: • The programme for construction
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Page 140 and 141: Starting the construction work 125
Page 142 and 143: Starting the construction work 127
Page 144 and 145: 12.2 Levelling Site surveys, invest
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Page 148 and 149: instance, it will have to be starte
Page 152 and 153: For grading analyses of soils 4. A
Page 154 and 155: Site surveys, investigations and la
Page 156 and 157: Contract state that the employer wi
Page 158 and 159: The drainage of clay or clay and si
Page 160 and 161: General files (Series 1-9) The resi
Page 162 and 163: If an instruction does not vary the
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Page 168 and 169: 13.8 Authorization of dayworks The
Page 172 and 173: with the engineer. If the decision
Page 174 and 175: Fig. 13.7. A page of a pipe stock b
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Page 180 and 181: 14 Programme and progress charts 14
Page 182 and 183: how any consequential delay to the
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Page 186 and 187: Programme and progress charts 171 d
Page 188 and 189: Height A.O.D. 200m 100m Pumping sta
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Page 192 and 193: Table 14.1 Estimated Final Cost of
Page 194 and 195: Measurement and bills of quantities
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Page 198 and 199: Measurement and bills of quantities
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Measurement and bills of quantities
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a tender is in the tenderer’s han
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other tenderers, etc., the contract
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Interim monthly payments 197 28 day
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Interim monthly payments 199 paid t
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Interim monthly payments 201 into d
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or for which contractual dates for
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Interim monthly payments 205 the co
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Variations and claims 207 reaching
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Variations and claims 209 Extensive
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The problem of setting rates for ne
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Variations and claims 213 that the
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costs. The problem is that borings
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17.10 Delay claims Variations and c
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Variations and claims 219 Some othe
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concerning a contractor’s claim,
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17.16 Arbitration Under the ICE con
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18 Earthworks and pipelines 18.1 Ex
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The grab has a low output rate, but
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match the timing of empty vehicles
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are then more clearly revealed. The
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minimum rise or fall. The preferred
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Earthworks and pipelines 235 The cr
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Table 19.1 Site concreting and rein
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Site concreting and reinforcement 2
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eason, the contractor has to take s
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Acceptance of tender 76 ACE (Assn.
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Design options 24 et seq. Design an
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One stop shop 15 Opening tenders 71
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Time schedule of key dates 168 Tran
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Plate 2a. An early use of a large t
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Plate 4a. Rollers compacting side s
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Plate 6b. Steel piling sometimes do
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Plate 8a. Presumably somebody thoug
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Plate 10a. It is almost universal t
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Plate 12a. On any job not properly
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Plate 14a. The typical fluidity of
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Plate 16a. If reinforcement is not
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Civil Engineering Project Management (4th Edition)

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