Load Resistance Factor Design of Axially Loaded Pile Based on Load Test Results

Abstract

The present study proposes a procedure to determine partial factors in reliability based design format for pile foundations,considering bias as well as uncertainty in the parameters that represent soil-pile interaction. These issues are addressed using pile load-settlement test data from case studies obtained from the literature. The pile ultimate capacities are evaluated considering three different failure criteria. The uncertainties in the pile-soil interface parameters as well as pile ultimate capacity are quantified in Monte Carlo framework from the measured data by utilizing the closed form "$t-z$" method. Considering dead load to live load ratios as calibration points, the target reliability index is calculated based on existing code safety-checking format. The optimal partial factors are determined such that the difference between reliability index based on limit state equations expressed in terms of partial factors and target reliability index is minimum. Finally, it is observed that optimal partial factors enable rational choice of allowable load on pile foundation