Pile Design and Construction Practice, Fifth edition

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Ground investigations, contracts and testing 521 of load testing since the failure load on the pile is not known with any certainty until the test is made. The ML test is best suited for contract work, particularly for proof loading tests on working piles. It is also suitable for use where empirical methods are employed to predict the ultimate load from measurement of residual deflections after returning the test load to zero at four or five stages up to the maximum (see below). The load at each stage is held until the rate of settlement has decreased to less than 0.25 mm/hour and is still decreasing. EC7-1 Clause 7.5 deals with pile load tests in general and outlines procedures for static and dynamic load tests, trial piles and testing working piles. BS EN 1536 refers to EC7 requirements giving recommendations for ML, CRP, dynamic and integrity testing which are slightly different from the BS 8004 procedures. For example, in ML tests the loads should be constant at each of at least six stages for a specified duration and unless otherwise stated the displacement rate should be less than 0.1 mm/20 minutes at the end of each stage. For CRP tests the rate of displacement should be constant at approximately 1 mm per minute, unless otherwise agreed. BS EN 12699 is less prescriptive for displacement piles, but requires testing to be in accordance with the relevant parts of EC7 and the specifications. The section of the ICE Specification dealing with static load tests defines the Specified Working Load (SWL) as ‘the specified load on the head of a pile as stated in the relevant Particular Specification’ or in provided schedules. This is differentiated from the Design Verification Load (DVL) which is defined as ‘a load which will be substituted for the specified working load for the purpose of a test and which may be applied to an isolated or singly loaded pile at the time of testing the given conditions of the Site’. The DVL takes into account special conditions which may not apply to all piles on the site such as negative shaft friction, or variations in pile head casting level. The ICE recommends that a proof load test should normally be the sum of the DVL plus 50% of the SWL applied in the sequence shown in Table 11.4 for multi-cyclic pile tests (reproduced with permission of Thomas Telford Limited). Table 11.4 Loading sequence for proof load test to a maximum of 100% DVL plus 50% SWL Load Minimum time of holding load 25% DVL 30 minutes 50% DVL 30 minutes 75% DVL 30 minutes 100% DVL 6 hours 75% DVL 10 minutes 50% DVL 10 minutes 25% DVL 10 minutes 0 1 hour 100% DVL 1 hour 100% DVL � 25% SWL 1 hour 100% DVL � 50% SWL 6 hours 100% DVL � 25% SWL 10 minutes 100% DVL 10 minutes 75% DVL 10 minutes 50% DVL 10 minutes 25% DVL 10 minutes 0 1 hour
522 Ground investigations, contracts and pile testing With regard to loading procedures, EC7 Clause 7.5.2.1 only refers in a note to the recommended procedure ‘Axial Pile Loading Test, Suggested Method’as published in the ASTM Geotechnical Testing Journal, June 1985, pp. 79–90. This is generally followed in current European practice. However, ISSMGE has produced a recommendation document (11.19) for the execution and interpretation of axial static pile load tests which is consistent with EC7 philosophy and is likely to form the basis of a new European standard. A note in Clause 7.5.3 refers to the procedures for dynamic tests in ASTM Designation D4945, ‘Standard Test Method for High-Strain Dynamic Testing of Piles’. The ASTM axial load procedure can be used for a test to twice the working load. If it is desired to obtain the ultimate load on a preliminary test pile it is useful to adopt the ML method for up to twice the working load, and then to continue loading to failure at a constant rate of penetration. A further modification of the ML test consists of returning the load to zero after each increment. This form of test is necessary if the net settlement curve is used as the basis of defining the failure load (see Section 11.4.2). It is essential to maintain a constant rate of load application as specified in EC7. It has been found that the slower the rate the smaller is the ultimate failure load. Hence the need for standardization both for ML and CRP testing. CRP and ML tests use the same type of loading arrangements and pile preparation. A square cap is cast onto the head of a concrete pile with its underside clear of the ground surface. Steel piles are trimmed square to their axis and a steel plate is welded to the head, stiffened as necessary by gussets. Suitable loading arrangements for applying the load to the pile by a hydraulic jack using as the reaction either kentledge, tension piles or cable anchors are shown in Figures 11.7, 11.8 and 11.9 respectively. The clearances between the pile and the reaction support systems are noted in each case. These are necessary to avoid the induced horizontal pressures from the supports having an appreciable effect on the shaft friction and base load of the test pile. It is uneconomical to space the supports so widely apart that all effects are eliminated, and if necessary the contribution of these surcharge effects should be calculated and allowed for in the interpretation of the test results. Angle lacing and tie bolt Kentledge blocks Timber spacers Stiffeners Universal beams Bracing Load cell Clamp Dial gauge 1.3 m minimum Clear space U.B. Hydraulic jack Timber Cap cast on to head of test pile crib Universal beams Test pile Figure 11.7 Testing rig for compressive test on pile using kentledge for reaction. Supports for four dial gauges
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Pile Design and Construction Practi
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Pile Design and Construction Practi
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Contents Preface to fifth edition i
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7.3 Designing piles to resist drivi
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Preface to fifth edition Piling rig
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Preface to fifth edition xi Pearson
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Chapter 1 General principles and pr
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(a) Backfill Bulb of pressure Appli
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are allowed to be used by Eurocode
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application of different load facto
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Load transfer The contractor’s gu
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(7) Jacked-down steel tube with clo
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Types of pile 13 needed to avoid cr
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(a) (b) Precast concrete Head of ti
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Table 2.2 Modification factor K 2 b
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4d d 10 mm M.S. plate sleeve tarred
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Table 2.3 Working loads and maximum
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Cement content �300 kg/m3 �325
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Types of pile 25 Table 2.5 BS 8004
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(a) (b) (c) (d) Cast iron or cast s
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Sheathing Bottom boards Figure 2.9
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Misplaced bearers Lifting holes Cra
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Section Bayonet plug Plan Locking p
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Existing foundation Precast pile ca
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Types of pile 37 Where very long le
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Types of pile 39 rotate during driv
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Types of pile 41 Because of their r
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(a) (b) Types of pile 43 Figure 2.2
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(a) (b) Welds Welds Types of pile 4
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(a) M.S. plate shoe Welds (b) 2.2.6
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Types of pile 49 brittle fracture r
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(a) (b) (c) Hammer Driving tube Con
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Types of pile 53 all cast-in-place
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Figure 2.28 The TaperTube pile.
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(a) (b) Figure 2.29 (a) The ScrewSo
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Types of pile 59 The simplest form
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Types of pile 61 Transverse reinfor
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Types of pile 63 completion the res
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Types of pile 65 permanently in the
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Types of pile 67 (3) Construction o
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Types of pile 69 can withstand fair
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Chapter 3 Piling equipment and meth
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Piling equipment and methods 73 A r
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Maximum height 26.32 m Usable leade
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Figure 3.4 Liebherr LRH 400 48 m lo
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Piling equipment and methods 79 the
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Piling frame Single-acting hammer S
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Guides for engaging leaders Steam o
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Table 3.1 Characteristics of some s
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Table 3.2 Characteristics of some h
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Piling equipment and methods 89 Tab
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Table 3.4 Characteristics of some d
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Figure 3.16 Driving a pile casing w
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Table 3.5 Continued Piling equipmen
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Soil resistance to driving (MN) 25
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Figure 3.19 Noise-abatement tower u
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Dolly M.S. plate Plastics Hardwood
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Standard elbow bend Detachable scre
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Figure 3.24 Discharging concrete in
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Piling equipment and methods 107 Fi
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Table 3.6 Continued Piling equipmen
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Figure 3.30 Top-hinged under-reamin
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Rotary table Hydraulic motor Water
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Piling equipment and methods 121 sl
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Pile head Pile base 2 holes ∅ 4 m
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Piling equipment and methods 125 Ca
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Piling equipment and methods 127 sm
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Piling equipment and methods 131 Th
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Piling equipment and methods 133 th
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Piling equipment and methods 135 Pi
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Piling equipment and methods 137 ve
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Chapter 4 Calculating the resistanc
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O C Settlement A Reloading Load B U
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Resistance of piles to compressive
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for spread foundations in various c
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structural actions and A2 to geotec
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Geometrical data are concerned with
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Figure 4.3 Failure surfaces for com
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Depth below ground level in m 5.6 1
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(a) (b) Peak adhesion factor a p Le
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orehole or test profile over the pe
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Effective length Shaft friction not
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4.3 Piles in coarse-grained soils 4
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Depth below ground surface (m) Resi
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Depth of penetration (m) 0 0 5 10 1
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using standard penetration tests or
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� � Resistance of piles to comp
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Safety factors generally used in th
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Depth to NAP datum (m) Cone resista
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The conditions at the interface can
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The shear modulus G in equation 4.3
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2.0 OD tubular steel pile with clos
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where Resistance of piles to compre
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eached the point of ultimate resist
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(4) Obtain the safe end-bearing loa
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Vertical force, t t-z curve Vertica
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where the bearing capacity factor:
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and RQD of the rock as shown in Tab
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Depth below ground level (m) 0 5 10
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settlement of the pile are summariz
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Rock socket reduction factor a 1.0
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Table 4.17 � and � values of we
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Influence factor, l p 2.0 1.6 1.2 0
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(a) (b) No load on pile head Residu
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a closed end into a deep deposit of
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Average shearing strength along pil
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It is assumed that the shear streng
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Depth below ground level (m) Figure
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Figure 4.45 Depth below ground leve
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Depth of h(m) Segment (m bql) � h
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For a wall thickness of 19 mm in mi
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Pile groups under compressive loadi
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24.0 m 16.0 m The comparative group
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where c � cohesion intercept of s
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Inclination factor, i c Inclination
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z/B 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
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Compressive stress 1.5 q n q n B A
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E u/c u 3000 2500 2000 1500 1000 50
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0 0 1 2 3 4 H/B 5 6 7 8 9 0 1 2 3 4
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D LB LB D 0.50 0 0.1 0.2 0.3 0.4 0.
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Initial tangent constrained modulus
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factor N for which Schmertmann sugg
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0 0 2 4 H/B 6 8 10 Influence factor
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Overall loading 100 kN/m2 (a) (b) (
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(a) (b) (c) (d) Pile groups under c
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Depth below ground level in m 5 10
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For the arrangement of the piles sh
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Soft clay Sand B/2 5 11.2 m Figure
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Unit negative skin friction at top
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Chapter 6 The design of piled found
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(a) Tie rod Wholly compression Whol
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esistance of cylindrical augered fo
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in the ground is assumed to be equa
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Section 3.3.1. Enlargements cannot
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Piles to resist uplift and lateral
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Spacer Top of hard rock Drilling pi
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where m is the modular ratio of ste
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Table 6.3 Examples of bond stress b
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Top of rock 30˚ 30˚ Figure 6.15 F
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(b) P/n & �Vm Vc 2.0 1.8 1.6 1.4
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Table 6.4 Partial resistance factor
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and adjustment, starting with a ver
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Coefficient of subgrade modulus var
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where e is the height from the grou
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and Thus from Figure 6.24 deflectio
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(a) Deflection coefficient Ay (c) D
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(a) (b) (c) Depth coefficient Z 0 1
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Horizontal load H; Bending moment =
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Methods of drawing sets of p-y curv
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Calculations to determine the ultim
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(a) (b) Pressure Soil reaction p Ps
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Z�x/R 0 1.0 2.0 3.0 4.0 5.0 M(z)
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(a) yroGc H0 Ep Gc 1/7 (b) 0 0 0.1
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(a) determining the compressive and
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A X Z B R A Resultant R R B Y C D R
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6.8 FREEMAN, C. F., KLAJNERMAN, D.,
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Thus the load to be carried by anch
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If high-tensile steel (which has a
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sustained horizontal load which can
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Calculating the allowable horizonta
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Pile cap (Weight�2475 kN) F E D C
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The resultant of the vertical and h
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The Brinch Hansen bearing capacity
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Modulus of elasticity of pile � 2
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Chapter 7 Some aspects of the struc
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(a) (b) (c) Lifting rope Lifting po
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7.3 Designing piles to resist drivi
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Structural design of piles and pile
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should not arise if the piles are d
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(a) (b) (c) M.S.plate cover M.S.cap
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45˚ Structural design of piles and
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X Column Y9 Y9 Y Critical section f
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7.9 The design of pile capping beam
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Damp-proof course Cranked vent Grou
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(a) (b) Deck of wharf Fender Rubber
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(a) (b) y y e z f A The bending mom
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Piling for marine structures 403 th
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Pipe trunkways Hose handling platfo
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Piling for marine structures 407 8.
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Piling for marine structures 409 sh
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In SI units, equation 8.8 becomes f
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The natural frequency of the member
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The empirical equation of Korzhavin
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Piling for marine structures 417 re
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Table 8.3 Minimum safety factors fo
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Piling for marine structures 421 th
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Piling for marine structures 423 sh
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8.21 GERWICK, B. C. Construction of
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Soil resistance p in kN per m of de
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From Figures 6.29a and b the comput
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giving 9.7y � 0.26, y � 0.26
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From �7.5 to �3.0 m: no increas
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Miscellaneous piling problems 435 W
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9.2 Piling for underpinning Miscell
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Miscellaneous piling problems 439 B
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Miscellaneous piling problems 441 T
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Miscellaneous piling problems 443 p
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Longitudinal reinforcement is provi
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Light-gauge steel lining tubes Stow
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When inspecting the geological cond
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Miscellaneous piling problems 451 f
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natural ‘freeze-back’ around th
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Miscellaneous piling problems 455 b
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Miscellaneous piling problems 457 w
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Drainage layer 8.0 m 6.0 m Fill 1.0
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p m/c u 10.5 2p 0 and the mean hori
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Bridge abutment support piles Emban
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Figure 9.23 Drilling equipment for
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Max. water level +16 m Min. water l
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2-4 m marine clay dredged out MHW R
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Page 490 and 491: The ground temperature around the p
Page 492 and 493: 9.40 URANOWSKI, D. D., DODDS, S., a
Page 494 and 495: The durability of piled foundations
Page 496 and 497: and European Standards as shown in
Page 500 and 501: martesia with some teredo, and at C
Page 512 and 513: economics, taking into account the
Page 514 and 515: Depth of borehole 1.5 B 1 in 4 B Gr
Page 516 and 517: Ground investigations, contracts an
Page 520 and 521: (a) DCP n (blows/100 mm) 40 35 30 2
Page 530 and 531: Table 11.2 Daily pile record for dr
Page 532 and 533: Paper fixed to pile by adhesive tap
Page 540 and 541: Figure 11.10 Patented arrangement f
Page 542 and 543: following expressions: (11.1) Load
Page 544 and 545: (b) Settlement of pile head in mm S
Page 546 and 547: (a) Settlement � (mm) 0 0 4 8 Gro
Page 552 and 553: experience to give reasonably relia
Page 554 and 555: Appendix Properties of materials A.
Page 556: Subdivisions of Grades A to C chalk
Page 559 and 560: 544 Name index Davis, E. H. 354 Dav
Page 561 and 562: 546 Name index Schaaf, S. A. 424 Sc
Page 563 and 564: 548 Subject index contiguous piles
Page 565 and 566: 550 Subject index Pali Radice piles
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Pile Design and Construction Practice, Fifth edition

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