Design of Piles Under Cyclic Loading

Alain Puech, Grenoble-Alpes University, France   Jacques Garnier, Grenoble-Alpes University, France

• Foreword xiPreface  xvList of Symbols  xixChapter 1 SOLCYP Project 11.1 Motivations  11.2 The SOLCYP project 21.2.1 The ANR-SOLCYP program 31.2.2 The national SOLCYP project 41.2.3 Organization of the PN-SOLCYP  81.3 Content and nature of this book  91.4 Regulatory context 101.5 Bibliography  11Chapter 2 Scope and Field of Application of Recommendations 132.1 Variable loading and cyclic loading 132.2 Structures to which this discussion pertains  142.3 Effects of cyclic loading on the foundations 162.4 Types of piles 172.5 Types of soils 182.6 Bibliography  18Chapter 3 Cyclic Loading  213.1 General  213.2 Characterization of cyclic loads  223.2.1 Regular loading: definitions  223.2.2 Cyclic loading of soil samples in the laboratory  233.2.3 Real-world cyclic loading 243.3 Taking account of real cyclic loading in the design process  243.3.1 Principle and definitions  243.3.2 Counting methods 273.3.3 Damage laws 273.4 Bibliography  38Chapter 4 Introduction to Cyclic Degradation  414.1 Introduction  414.2 Cyclic degradation of soil properties 414.2.1 Recap of the response of soils to monotonic loading  414.2.2 Soil response to cyclic loading 424.2.3 Contour diagrams 444.2.4 Generalized contour diagrams 474.2.5 Obtaining contour diagrams for a particular soil  544.2.6 Cyclic degradation of the shear modulus 554.3 Cyclic degradation of soil–pile interfaces 594.3.1 General considerations on soil–pile interface tests 594.3.2 SOLCYP databank on direct shear soil–pile tests 664.4 Cyclic degradation of pile response 704.4.1 Piles subjected to axial cyclic loading 704.4.2 Piles subject to lateral cyclic loading 844.5 Appendices  914.5.1 Appendix 1: Program of CNL and CNS tests and parameters influencing their outcome 914.5.2 Appendix 2: CNS tests Corrections to be made to the raw measurements  954.6 Bibliography  96Chapter 5 SOLCYP Design Strategy 1015.1 General methodology 1015.2 Knowledge of loads  1035.3 Analysis of regulatory loads  1055.4 Criteria of cyclic severity for axial loads 1065.4.1 Axial capacity of piles: definitions 1065.4.2 Use of the cyclic stability diagram 1075.4.3 Influence of soil–pile relative stiffness  1145.5 Cyclic severity criteria for transverse loading 1155.5.1 Case of sands 1155.5.2 Case of clays 1175.6 Detailed characterization of the cyclic loads 1195.7 Cyclic pile design methods  1215.8 Obtaining the parameters 1225.9 Bibliography  122Chapter 6 Behavior of Piles Subject to Cyclic Axial Loading  1256.1 Introduction  1256.2 Large international programs  1276.3 Tests in clay soils 1326.3.1 Normally consolidated to slightly overconsolidated clays  1326.3.2 Highly overconsolidated clays 1376.3.3 Comparisons of the results 1446.4 Tests in sands 1466.4.1 Silica sand 1466.4.2 Carbonate soils  1586.5 About the static load-bearing capacity  1606.5.1 Ageing in sands  1606.5.2 Effect of time and preshearing in clays  1616.5.3 Softening  1626.5.4 Loading rate  1626.6 Summary 1636.7 Appendix: cyclic loading tests on piles at the Merville site  1656.7.1 Introduction  1656.7.2 Results obtained on two driven piles (B1 and B4) 1666.7.3 Results obtained on bored (CFA) piles  1676.7.4 Results obtained on bored screw piles  1696.8 Bibliography  170Chapter 7 Design of Piles Subjected to Cyclic Axial Loading  1777.1 Introduction  1777.2 General principles 1787.3 The NGI approach 1807.3.1 Fundamental principles  1807.3.2 PAXCY and PAX2 programs 1827.4 The ICL approach 1847.4.1 Basic principle  1847.4.2 The ABC global method  1857.4.3 Local applications of the ABC method  1887.5 The RATZ-CYCLOPS suite of programs 1887.6 The SCARP program 1917.6.1 Description of the SCARP program 1917.6.2 Calibration of the SCARP program 1957.7 Finite Element Method approaches 2017.8 The SOLCYP approach for non-cohesive soils  2037.8.1 General principles 2037.8.2 Choice of parameters to characterize the soil–pile system 2047.8.3 Modeling of the results of direct soil–structure shear 2077.8.4 Modeling by the t–z envelope curve method 2087.8.5 Modeling by the method of t–z cyclic curves (TZC software)  2117.8.6 FEM modeling  2177.8.7 Case of driven piles  2247.9 Bibliography  225Chapter 8 Behavior of Piles Subject to Cyclic Lateral Loading 2338.1 Soil–pile interaction under lateral loading 2338.1.1 Relative stiffness 2348.1.2 Concept of lateral reaction 2368.1.3 Crucial role of surface layers 2368.2 Main experimental data  2388.3 Available data on the effect of the cycles 2408.3.1 Effect of cycles on the pile’s lateral displacement 2408.3.2 Effect of cycles on the maximum bending moment in the pile 2528.3.3 Effect of cycles on the P–y reaction curves  2568.4 Contribution of the SOLCYP project  2598.4.1 Context and scope of the studies conducted 2598.4.2 Testing conditions  2608.5 Data obtained on the effect of cycles 2638.5.1 Case of sands 2648.5.2 Case of clays 2718.6 Final overview of the data on the effect of cycles 2858.6.1 Effects on pile head displacement  2868.6.2 Effects on the maximum moment and the reactions in the soil 2918.7 Bibliography  292Chapter 9 Design of Piles Subject to Cyclic Lateral Loading  2999.1 Recap of the current rules 3009.2 Methodology to take account of cyclic loads 3039.3 Taking account of the cycles by the global method SOLCYP-G  3059.3.1 Principles of the global method 3059.3.2 Conventional limit load and failure load 3059.3.3 Degree of relative stiffness of the pile and limits of flexible and rigid piles 3089.3.4 Presizing of the pile subject to the maximum static load Hmax  3119.3.5 Cyclic severity criteria  3149.3.6 Effect of cycles on the pile head displacement 3159.3.7 Effect of cycles on the maximum bending moment  3199.4 Taking account of cycles by a local method SOLCYP-L 3199.4.1 Principle of the local method 3199.4.2 Determination of the P-multipliers for monotonic P–y curves  3209.5 Domains of validity and example of application 3239.5.1 Domains of validity of the global method SOLCYP-G and local method SOLCYP-L 3239.5.2 Example of application of the global and local methods 3279.6 Conclusion  3459.7 Bibliography  345Chapter 10 Determination of Cyclic Parameters for Pile Design 34710.1 Introduction  34710.2 Parameters for the design of piles subjected to cyclic loads 34810.2.1 Mineralogy  35010.2.2 Parameters for monotonic calculations 35110.2.3 Cyclic parameters  35210.2.4 Consolidation parameters 35210.2.5 Remolding parameters  35310.3 Obtaining the parameters for the design of piles subjected to cyclic loading 35310.3.1 Lab tests 35310.3.2 In situ tests  36510.4 Bibliography 370Chapter 11 Recommendations for Testing Piles Under Cyclic Loading 37711.1 Introduction  37711.2 Reasons for the tests 37811.3 The different test methods  37911.4 Contribution of calibration chamber tests: Axial loading 38111.5 Contribution of centrifuge tests: Axial or transverse loading  38311.6 In situ axial loading tests  38411.6.1 Objectives of the test  38411.6.2 Design support tests (FEED tests) 38511.6.3 Validation tests (Non-Working Pile Tests) 39111.6.4 Control tests (Working Pile Tests) 39311.7 Transverse loading tests in situ  39411.7.1 Objectives and representativity of tests 39411.7.2 Design support tests (FEED tests) 39511.7.3 Validation tests (Non-Working Pile Tests) 39911.7.4 Control tests (Working Pile Tests) 40011.8 Appendix 1: Recap on scaling effects 40111.8.1 Tests on reduced-scale models in the lab  40211.8.2 Tests of piles in situ 40411.9 Appendix 2: In situ axial loading 40411.9.1 Test setup 40411.9.2 Instrumentation and data acquisition 40611.10 Appendix 3: Transverse loading in situ 40911.10.1 Test setup  40911.10.2 Instrumentation and data acquisition  41111.11 Bibliography 413Index 417