Lateral Response of a Single Pile under Combined Axial and Lateral Cyclic Loading in Sandy Soil

Muqdad Abdallah Kahribt,Jasim M Abbas

doi:10.28991/cej-03091133

Abstract

According to practical situation, there have been limited investigations on the response of piles subjected to combined loadings especially when subjected to cyclic lateral loads. Those few studies led to contradictory results with regard to the effects of vertical loads on the lateral response of piles. Therefore, a series of experimental investigation into piles in dense sand subjected to combination of static vertical and cyclic lateral loading were conducted with instrumented model piles. The effect of the slenderness ratio (L/D) was also considered in this study (i.e. L/D= 25 and 40). In addition, a variety of two-way cyclic lateral loading conditions were applied to model piles using a mechanical loading system. One hundred cycles were used in each test to represent environmental loading such as offshore structures. It was found that under combined vertical and cyclic lateral loads the lateral displacement of piles decreased with an increase in vertical load whereas it causes large vertical displacements at all slenderness ratios. In addition, for all loading conditions the lateral, vertical (settlement and upward) displacements and bending moments increased as either the magnitude of cyclic load or the number of cycles increases.

Highlights

Pile foundations are widely used to support various important structures such as offshore platforms, jetties, wharfs, docks, dolphin structures, and bridges
The results of experimental work for the effect of vertical loading on response of piles subjected to cyclic lateral loading are divided to three parts (lateral displacement at pile head, Vertical displacementat pile cap and bending moment along pile)
The results show that, in piles subjected to combination of vertical and cyclic lateral loading, there is a consider able decrease in the lateral displacement under increasing the vertical load levels as compared to the pure cyclic lateral load case

Summary

Introduction

Pile foundations are widely used to support various important structures such as offshore platforms, jetties, wharfs, docks, dolphin structures, and bridges These piles are used to support vertical loads, lateral loads and combination of vertical and lateral loads. In an overview of lateral loaded pile studies, the vertical and lateral responses of piles are often evaluated separately neglecting their possible interaction This would lead to an erroneous design, as pile foundations for several types of structures are subjected to simultaneous vertical and lateral loading. The methods of analysis commonly used in predicting the response of a single pile are the elastic half space method, and the nonlinear subgrade reaction method Both of these methods assume that axial and lateral loads act independently and that there is no interaction. The influence of vertical loads on the lateral response of pile foundations needs to be accounted for in optimum design; only

Methods

Results

Conclusion