Calibrating Resistance Factors of Single Bored Piles Based on Incomplete Load Test Information

This paper addresses an issue often encountered in calibrating resistance factors for pile ultimate capacities based on load test database. In practice, many pile load tests are not conducted to failure but rather only to a multiple of the design load (e.g. twice the design load). This leads to a difficult situation of incomplete information: for these test results, the ultimate bearing capacities of the test piles are unknown. How can these test results still be used to calibrate resistance factors of piles? A full probabilistic framework is proposed in this research to resolve this issue. A local pile test database of Taipei (Taiwan) is presented for demonstration. The analysis results show that the inclusion of the incomplete pile load test data helps in calibrating the resistance factors. Moreover, it is found that the calibrated resistance factors are consistent with the safety factors that are adopted in the current Taiwan design code.