Load-Transfer Method for Piles under Axial Loading and Unloading

Abstract

This paper presents two modifications to the traditional formulation of the load-transfer method; a distinct unloading path is defined for the load-transfer functions, and the displacement variable is modified to consider the effects of passive soil displacements. The discrete formulation can account for different properties along the pile depth, as in the case of soil layering. Modeling distinct unloading functions enables loading cycles to be simulated as well as the analysis of residual loads. An instrumented pile load test is used to calibrate the method. Example computations are presented and discussed, highlighting the main features of the model.