Calibrating Resistance Factors of Single Bored Piles Based on Incomplete Load Test Results
Publication: Journal of Engineering Mechanics
Volume 137, Issue 5
Abstract
This paper addresses a problem often encountered in calibrating resistance factors for the ultimate capacities of piles based on load test databases. In practice, many pile load tests are not conducted to failure but only to a multiple (e.g., 2) of 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 problem. 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 enhances the stability of the calibrated resistance factors. For a target reliability index of 3, the calibrated resistance factor is in the range of 0.4–0.66 for two design models adopted in the current Taiwan design code. Moreover, it is found that the safety factor adopted in the Taiwan design code corresponds to a reliability index larger than 3.5, which is reasonably conservative.
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Published In
Journal of Engineering Mechanics
Volume 137 • Issue 5 • May 2011
Pages: 309 - 323
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Mar 19, 2009
Accepted: Sep 28, 2010
Published online: Oct 27, 2010
Published in print: May 1, 2011
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