Single piles and pile groups under lateral loading

Guiding the professional through the complexities of lateral-load design, this book and CD-ROM combination introduces the procedures involved in piles and pile group design. This is a problem that can only be solved by accounting for the soil resistance as related to the lateral deflection of the pile.

Intricate equations are derived and fully explained, enabling the designer to find the critical loads, either causing a pile to be overloaded or causing too much lateral deflection. The CD-ROM contains simplified versions of two required programs that allow the reader to check the solutions of some of the examples given in the book and to find answers to related problems.

Preface	p. XV
1 Techniques for Design	p. 1
1.1 Introduction	p. 1
1.2 Occurrence of laterally loaded piles	p. 2
1.3 Nature of the soil response	p. 3
1.4 Response of a pile	p. 7
1.4.1 Introduction	p. 7
1.4.2 Static loading	p. 7
1.4.3 Cyclic loading	p. 7
1.4.4 Sustained loading	p. 8
1.4.5 Dynamic loading	p. 9
1.5 Models for use in analyses of a single pile	p. 11
1.5.1 Elastic pile and elastic soil	p. 11
1.5.2 Elastic pile and finite elements for soil	p. 12
1.5.3 Rigid pile and plastic soil	p. 12
1.5.4 Characteristic load method	p. 13
1.5.5 Nonlinear pile and p-y model for soil	p. 14
1.6 Models for groups of piles under lateral loading	p. 16
1.7 Status of current state-of-the-art	p. 18
2 Derivation of Equations and Methods of Solution	p. 21
2.1 Introduction	p. 21
2.2 Derivation of the differential equation	p. 21
2.2.1 Solution of Reduced Form of Differential Equation	p. 25
2.2.2 Solution of the Differential Equation by Difference Equations	p. 29
2.3 Solution for E[subscript py] = k[subscript py]x	p. 35
2.3.1 Dimensional Analysis	p. 36
2.3.2 Equations for E[subscript py] = k[subscript py]x	p. 41
2.3.3 Example Solution	p. 42
2.3.4 Discussion	p. 46
2.4 Validity of the mechanics	p. 47
3 Models for Response of Soil and Weak Rock	p. 49
3.1 Introduction	p. 49
3.2 Mechanics concerning response of soil to lateral loading	p. 50
3.2.1 Stress-deformation of soil	p. 50
3.2.2 Proposed model for decay of E[subscript s]	p. 50
3.2.3 Variation of stiffness of soil (E[subscript s] and G[subscript s]) with depth	p. 51
3.2.4 Initial stiffness and ultimate resistance of p-y curves from soil properties	p. 53
3.2.5 Subgrade modulus related to piles under lateral loading	p. 59
3.2.6 Theoretical solution by Skempton for subgrade modulus and for p-y curves for saturated clays	p. 60
3.2.7 Practical use of Skempton's equations and values of subgrade modulus in analyzing a pile under lateral loading	p. 62
3.3 Influence of diameter on p-y curves	p. 64
3.3.1 Clay	p. 64
3.3.2 Sand	p. 64
3.4 Influence of cyclic loading	p. 65
3.4.1 Clay	p. 65
3.4.2 Sand	p. 66
3.5 Experimental methods of obtaining p-y curves	p. 67
3.5.1 Soil response from direct measurements	p. 67
3.5.2 Soil response from experimental moment curves	p. 67
3.5.3 Nondimensional methods for obtaining soil response	p. 68
3.6 Early recommendations for computing p-y curves	p. 68
3.6.1 Terzaghi	p. 68
3.6.2 McClelland and Focht for clay (1958)	p. 70
3.7 p-y curves for clay	p. 70
3.7.1 Selection of stiffness of clay	p. 70
3.7.2 Response of soft clay in the presence of free water	p. 72
3.7.3 Response of stiff clay in the presence of free water	p. 75
3.7.4 Response of stiff clay with no free water	p. 82
3.8 p-y curves for sands above and below the water table	p. 84
3.8.1 Detailed procedure	p. 84
3.8.2 Recommended soil tests	p. 87
3.8.3 Example curves	p. 87
3.9 p-y curves for layered soils	p. 87
3.9.1 Method of Georgiadis	p. 88
3.9.2 Example p-y curves	p. 89
3.10 p-y curves for soil with both cohesion and internal friction	p. 91
3.10.1 Background	p. 91
3.10.2 Recommendations for computing p-y curves	p. 92
3.10.3 Discussion	p. 96
3.11 Other recommendations for computing p-y curves	p. 97
3.11.1 Clay	p. 97
3.11.2 Sand	p. 97
3.12 modifications to p-y curves for sloping ground	p. 98
3.12.1 Introduction	p. 98
3.12.2 Equations for ultimate resistance in clay	p. 98
3.12.3 Equations for ultimate resistance in sand	p. 99
3.13 Effect of batter	p. 100
3.14 Shearing force at bottom of pile	p. 101
3.15 p-y curves for weak rock	p. 101
3.15.1 Introduction	p. 101
3.15.2 Field tests	p. 102
3.15.3 Interim recommendations	p. 102
3.15.4 Comments on equations for predicting p-y curves for rock	p. 106
3.16 Selection of p-y curves	p. 106
3.16.1 Introduction	p. 106
3.16.2 Factors to be considered	p. 106
3.16.3 Specific suggestions	p. 107
4 Structural Characteristics of Piles	p. 109
4.1 Introduction	p. 109
4.2 Computation of an equivalent diameter of a pile with a noncircular cross section	p. 109
4.3 Mechanics for computation of m[subscript ult] and e[subscript p]i[subscript p] as a function of bending moment and axial load	p. 111
4.4 Stress-strain curves for normal-weight concrete and structural steel	p. 114
4.5 Implementation of the method for a steel h-section	p. 116
4.6 Implementation of the method for a steel pipe	p. 118
4.7 Implementation of the method for a reinforced-concrete section	p. 119
4.7.1 Example computations for a square shape	p. 119
4.7.2 Example computations for a circular shape	p. 121
4.8 Approximation of moment of inertia for a reinforced-concrete section	p. 121
5 Analysis of Groups of Piles Subjected to Inclined and Eccentric Loading	p. 125
5.1 Introduction	p. 125
5.2 Approach to analysis of groups of piles	p. 126
5.3 Review of theories for the response of groups of piles to inclined and eccentric loads	p. 126
5.4 Rational equations for the response of a group of piles under generalized loading	p. 129
5.4.1 Introduction	p. 129
5.4.2 Equations for a two-dimensional group of piles	p. 132
5.5 Laterally loaded piles	p. 136
5.5.1 Movement of pile head due to applied loading	p. 136
5.5.2 Effect of batter	p. 136
5.6 Axially loaded piles	p. 137
5.6.1 Introduction	p. 137
5.6.2 Relevant parameters concerning deformation of soil	p. 137
5.6.3 Influence of method of installation on soil characteristics	p. 139
5.6.4 Methods of formulating axial-stiffness curves	p. 140
5.6.5 Differential equation for solution of finite-difference equation for axially loaded piles	p. 142
5.6.6 Finite difference equation	p. 145
5.6.7 Load-transfer curves	p. 145
5.7 Closely-spaced piles under lateral loading	p. 151
5.7.1 Modification of load-transfer curves for closely spaced piles	p. 151
5.7.2 Concept of interaction under lateral loading	p. 152
5.7.3 Proposals for solving for influence coefficients for closely-spaced piles under lateral loading	p. 152
5.7.4 Description and analysis of experiments with closely-spaced piles installed in-line and side-by-side	p. 155
5.7.5 Prediction equations for closely-spaced piles installed in-line and side-by-side	p. 158
5.7.6 Use of modified prediction equations in developing p-y curves for analyzing results of experiments with full-scale groups	p. 160
5.7.7 Discussion of the method of predicting the interaction of closely-spaced piles under lateral loading	p. 173
5.8 Proposals for solving for influence coefficients for closely-spaced piles under axial loading	p. 173
5.8.1 Introduction	p. 173
5.8.2 Concept of interaction under axial loading	p. 174
5.8.3 Review of relevant literature	p. 174
5.8.4 Interim recommendations for computing the efficiency of groups of piles under axial loading	p. 177
5.9 Analysis of an experiment with batter piles	p. 178
5.9.1 Description of the testing arrangement	p. 178
5.9.2 Properties of the sand	p. 179
5.9.3 Properties of the pipe piles	p. 181
5.9.4 Pile group	p. 181
5.9.5 Experimental curve of axial load versus settlement for single pile	p. 182
5.9.6 Results from experiment and from analysis	p. 183
5.9.7 Comments on analytical method	p. 185
6 Analysis of Single Piles and Groups of Piles Subjected to Active and Passive Loading	p. 187
6.1 Nature of lateral loading	p. 187
6.2 Active loading	p. 187
6.2.1 Wind loading	p. 187
6.2.2 Wave loading	p. 189
6.2.3 Current loading	p. 194
6.2.4 Scour	p. 195
6.2.5 Ice loading	p. 197
6.2.6 Ship impact	p. 198
6.2.7 Loads from miscellaneous sources	p. 198
6.3 Single piles or groups of piles subjected to active loading	p. 199
6.3.1 Overhead sign	p. 199
6.3.2 Breasting dolphin	p. 203
6.3.3 Pile for anchoring a ship in soft soil	p. 207
6.3.4 Offshore platform	p. 213
6.4 Passive loading	p. 223
6.4.1 Earth pressures	p. 223
6.4.2 Moving soil	p. 224
6.4.3 Thrusts from dead loading of structures	p. 226
6.5 Single piles or groups of piles subjected to passive loading	p. 226
6.5.1 Pile-supported retaining wall	p. 226
6.5.2 Anchored bulkhead	p. 231
6.5.3 Pile-supported mat at the Pyramid Building	p. 237
6.5.4 Piles for stabilizing a slope	p. 245
6.5.5 Piles in a settling fill in a sloping valley	p. 251
7 Case Studies	p. 259
7.1 Introduction	p. 259
7.2 Piles installed into cohesive soil with no free water	p. 260
7.2.1 Bagnolet	p. 260
7.2.2 Houston	p. 263
7.2.3 Brent Cross	p. 264
7.2.4 Japan	p. 267
7.3 Piles installed into cohesive soil with free water above ground surface	p. 269
7.3.1 Lake Austin	p. 269
7.3.2 Sabine	p. 272
7.3.3 Manor	p. 273
7.4 Piles installed in cohesionless soil	p. 276
7.4.1 Mustang Island	p. 276
7.4.2 Garston	p. 277
7.4.3 Arkansas River	p. 278
7.5 Piles installed into layered soil	p. 283
7.5.1 Talisheek	p. 283
7.5.2 Alcacer do Sol	p. 286
7.5.3 Florida	p. 288
7.5.4 Apapa	p. 288
7.6 Piles installed in c-o soil	p. 290
7.6.1 Kuwait	p. 290
7.6.2 Los Angeles	p. 291
7.7 Piles installed in weak rock	p. 293
7.7.1 Islamorada	p. 293
7.7.2 San Francisco	p. 295
7.8 Analysis of results of case studies	p. 298
7.9 Comments on case studies	p. 299
8 Testing of Full-Sized Piles	p. 303
8.1 Introduction	p. 303
8.1.1 Scope of presentation	p. 303
8.1.2 Summary of method of analysis	p. 303
8.1.3 Classification of tests	p. 303
8.1.4 Features unique to testing of piles under lateral loading	p. 304
8.2 Designing the test program	p. 304
8.2.1 Planning for the testing	p. 304
8.2.2 Selection of test pile and test site	p. 305
8.3 Subsurface investigation	p. 306
8.4 Installation of test pile	p. 309
8.5 Testing techniques loading arrangements and instrumentation at the pile head	p. 310
8.6 Loading arrangements and instrumentation at the pile head	p. 311
8.6.1 Loading arrangements	p. 311
8.6.2 Instrumentation	p. 313
8.7 Testing for design of production piles	p. 317
8.7.1 Introduction	p. 317
8.7.2 Interpretation of data	p. 317
8.7.3 Example Computation	p. 317
8.8 Testing for obtaining details on response of soil	p. 319
8.8.1 Introduction	p. 319
8.8.2 Preparation of test piles	p. 319
8.8.3 Test setup and loading equipment	p. 321
8.8.4 Instrumentation	p. 322
8.8.5 Calibration of test piles	p. 325
8.8.6 Soil borings and laboratory tests	p. 328
8.8.7 Installation of test piles	p. 332
8.8.8 Test procedures and details of loading	p. 334
8.8.9 Penetrometer tests	p. 335
8.8.10 Ground settlement due to pile driving	p. 338
8.8.11 Ground settlement due to lateral loading	p. 339
8.8.12 Recalibration of test piles	p. 339
8.8.13 Graphical presentation of curves showing bending moment	p. 340
8.8.14 Interpretation of bending moment curves to obtain p-y curves	p. 341
8.9 Summary	p. 346
9 Implementation of Factors of Safety	p. 347
9.1 Introduction	p. 347
9.2 Limit states	p. 347
9.3 Consequences of a failure	p. 348
9.4 Philosophy concerning safety coefficient	p. 350
9.5 Influence of nature of structure	p. 351
9.6 Special problem in characterizing soil	p. 351
9.6.1 Introduction	p. 351
9.6.2 Characteristic value of soil parameters	p. 352
9.7 Level of quality control	p. 353
9.8 Two general approaches to selecting the factor of safety	p. 353
9.9 Global approach	p. 354
9.9.1 Introductary comments	p. 354
9.9.2 Recommendations of the American Petroleum Institute	p. 355
9.10 Method of partial safety factors (psf)	p. 356
9.10.1 Introduction	p. 356
9.10.2 Suggested values for partial factors for design of laterally loaded piles	p. 356
9.10.3 Example computations	p. 358
9.11 Method of load and resistance factors (LRFD)	p. 358
9.11.1 Introduction	p. 358
9.11.2 Loads addressed by the LRFD specifications	p. 359
9.11.3 Resistances addressed by the LRFD specifications	p. 359
9.11.4 Design of piles by the LRFD specifications	p. 360
9.12 Concluding comments	p. 360
10 Suggestions for Design	p. 363
10.1 Introduction	p. 363
10.2 Range of factors to be considered in design	p. 363
10.3 Validation of results from computations for single pile	p. 364
10.3.1 Introduction	p. 364
10.3.2 Solution of example problems	p. 364
10.3.3 Check of echo print of input data	p. 364
10.3.4 Investigation of length of word employed in internal computations	p. 365
10.3.5 Selection of tolerance and length of increment	p. 365
10.3.6 Check of soil resistance	p. 365
10.3.7 Check of mechanics	p. 366
10.3.8 Use of nondimensional curves	p. 366
10.4 Validation of results from computations for pile group	p. 366
10.5 Additional steps in design	p. 367
10.5.1 Risk management	p. 367
10.5.2 Peer review	p. 367
10.5.3 Technical contributions	p. 367
10.5.4 The design team	p. 368
Appendices
A Broms method for analysis of single piles under lateral loading	p. 369
B Nondimensional coefficients for piles with finite length, no axial load, constant E[subscript p]I[subscript p], and constant E[subscript s]	p. 385
C Difference equations for solving the problem of step-tapered beams on foundations having variable stiffness	p. 395
D Instructions for use of student versions of computer programs LPILE and GROUP	p. 405
E Nondimensional curves for piles under lateral loading for case where E[subscript py] = K[subscript py]x	p. 409
F Tables of values of efficiency measured in tests of groups of piles under lateral loading	p. 419
G Horizontal stresses in soil near shaft during installation of a pile	p. 423
H Use of data from uninstrumented piles under lateral loading to obtain soil response	p. 429
I Eurocode principles related to geotechnical design	p. 435
J Discussion of factor of safety related to piles under axial load	p. 439
References	p. 443
Author Index	p. 457
Subject Index	p. 461

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