COMPUTER AIDED MODERATION OF PILE LOAD TEST DATA

Abstract

An estimate of load-settlement behaviour of piles is an important input in the design of pile foundations. Load test on piles are usually conducted to obtain this input. However, load tests are expensive and the results may be valid only for the particular pile and site conditions under test. In contrast, an analytical method predicts the load-settlement response quickly, in addition to being economical. The analytical method can be grouped into three major categories, viz., elastic continuum method, finite element method and load transfer method. In the present work, analytical procedure suggested by Ramasamy and Hazarika (2000) which is based on load transfer method has been adopted. A computer package PILEANA has been developed to carry out the analysis. Making use of the package results are obtained for a number of numerical problems to bring out the following: 1. Prediction of load-settlement behaviour for a given pile-soil system. 2. Comparison of predicted and observed load-settlement data. 3. Moderation of observed load-settlement curve to account for any possible change in ground conditions subsequent to load test. 4. Estimation of settlement of pile groups. Based on the results obtained it was found that the change in the ground conditions that could take place subsequent to the time of load test may have significant influence on the load-settlement behaviour of pile. Therefore, the results of the load test may not become valid under these changed conditions. Such situation are illustrated and a procedure of moderating the load-settlement curve observed in a load test to take care of changes that might occur in the pile and the soil conditions subsequent to the time of load test is suggested.