Interpretation of bi-directional pile load Tests using instrumented gauge data

Abstract

This study presents a method that is conventionally used for interpretation of a head-down pile load test, which is modified and extended for a bi-directional pile load test. A parabolic function is used to simulate the load transfer curve along a depth above or below the load cell. The coefficients of the function are obtained by fitting the measured gauge data. Three bored piles are tested using a bi-directional load cell that is installed in the middle of the pile shaft and the results are interpreted using the method of this study. An equivalent head-down load-displacement curve that is obtained using the presented method produces results that are in good agreement with those that are obtained using the conventional method. The relationship between mobilized unit skin friction and displacement that is obtained using the measurement data and using the presented method shows similar trend.