Evaluation of the effect of the efficiency of standard penetration test in the prediction of load capacity and settlement of precast piles

Abstract

In building designs, foundations must meet design requirements to ensure the safety of the work. Therefore, estimates of load capacity and foundation settlements are necessary. It is usual to make these estimates based on the results of field tests. The present work proposes an evaluation of the load capacity and settlement predictions of foundations in precast piles using semi-empirical methods based on the results of Standard Penetration Test (SPT), with and without consideration of the correction of the test efficiency. For this purpose, 7 piles, manufactured in reinforced concrete, and driven into typical soil profiles of the Metropolitan Region of Fortaleza (RMF) were analyzed. For the proposed evaluation, the results of load tests and Standard Penetration Test (SPT) were used. The predictions, estimated by semi-empirical methods, were compared to the values obtained experimentally by the load tests. The predictions, of load capacity and settlement, were made without correcting the efficiency of the SPT tests and, also, for the efficiency of 70%. The consideration of correcting the efficiency of Standard Penetration Test (SPT), both in calculations of load capacity and settlement, promoted more consistent predictions for almost all the situations analyzed.