Reliability Analysis of Bearing Capacity Equations for Drilled Shafts Socketed in Weathered Rock

Abstract

As the use of drilled shafts for the foundation of a large size structure increases, the evaluation of the reliable bearing capacity of a pile has become important. The purpose of this study is to examine the reliability of bearing capacity equations for drilled shafts socketed in weathered rock by comparing the bearing capacity values obtained by the bearing capacity equations with the measured ones. To this aim, 17 static load test data obtained from four field sites were collected, and based on these test data, the ultimate bearing capacity of rock-socketed piles were acquired. Three bearing capacity equations widely used in practice were selected for the reliability analysis. They are the AASHTO method (1996), Carter & Kulhawy method (1988), and FHWA method (1999). The comparison of the bearing capacity values showed that FHWA method predicted the bearing capacities most closely to the measured ones on average, whereas the Carter & Kulhawy method (1988) and AASHTO method (1996) consistently predicted bearing capacities conservatively with acceptable discrepancy.