Analytical methods for predicting load-displacement behaviour of piles

This thesis presents new methods for predicting pile response under different loading and soil conditions. The new methods offer practs engineers with a simple, quick and reliable tool for designing piles and ensuring that both safety and serviceability requirements are satisfied. In this thesis, an energy-based analytical approach for determining the dynamic response of piles subjected to dynamic loads is presented. The kinematic and potential energies of the pile-foundation system are minimized by a variational principle to obtain the governing equations of the pile-foundation system, along with the appropriate boundary conditions. Comparison with field data demonstrates the success of the new approach for predicting the resonant frequencies of laterally loaded piles. Energy-based methods are also developed for piles subjected to combined static loading. These methods are formulated for different constitutive models: linear-elastic, non-linear elastic and elasto-plastic models. In addition to energy-based methods, simple similarity methods have been developed to predict pile displacements. In the similarity methods, the load-displacement curve of a pile foundation can be obtained directly by scaling the stress-strain response obtained from a triaxial test on a representative soil sample. Linear scaling factors are presented and extensive verification is carried out against field data, centrifuge models and nonlinear finite element analysis.