Influence of Material Variability on the Seismic Response of Pile Foundation

Pile foundation response during earthquakes is strongly affected by the type of material used in pile construction. In the present study three different types of materials viz. concrete, wood and bamboo are used to construct pile foundation. Specimens of clean sand and clay soil are used to prepare the soil for test and the physical properties of that soil are evaluated. Next, earthquake response analyses are conducted to clarify the effect of the nonlinear soil-pile foundation system on the performance of pile foundation. The input shaking included sinusoidal earthquake accelerations. Pile displacement, acceleration, strain and earth pressure are found out using PULSE and MICRON software. Performance evaluation of the pile foundation is discussed on the basis of pile curvature.   Keywords: Soil-pile interaction, pile material, shake table test, curvature, PULSE, MICRON

Analytical methods for predicting load-displacement behaviour of piles

Abstract 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

Analysis of Laterally Loaded Piles in Multilayered Soil Deposits

This report focuses on the development of a new method of analysis of laterally loaded piles embedded in a multi-layered soil deposit treated as a three-dimensional continuum. Assuming that soil behaves as a linear elastic material, the governing differential equations for the deflection of laterally loaded piles were obtained using energy principles and calculus of variations. The differential equations were solved using both the method of initial parameters and numerical techniques. Soil resistance, pile deflection, slope of the deflected pile, bending moment and shear force can be easily obtained at any depth along the entire pile length. The results of the analysis were in very good agreement with three-dimensional finite element analysis results. The analysis was further extended to account for soil nonlinearity. A few simple constitutive relationships that allow for modulus degradation with increasing strain were incorporated into the analysis. The interaction of piles in groups was also studied