System Reliability Analysis of Defected Pile group Foundations
Abstract
Deep foundations design suffers some degrees of uncertainties. This thesis studies the behavior of defected pile group foundations installed in sand and calibrates the resistance factor of pile group foundation, utilizing a rational based system reliability analysis. This was achieved by conducting a comprehensive numerical parametric investigation using the computer program ABAQUS/Standard. The result of the parametric study showed that the presence of a defected pile in a pile group foundation causes lateral deflection of the pile cap and hence induces bending moment at the adjacent piles which affects the load distribution mechanism of the system. It was also found that the proposed resistance factor values varied from 0.31 to 0.61, 0.52 to 0.86, 0.34 to 0.63, and 0.45 to 0.96 for different design methods: Nordlund, Bluebook, β-Method, and SPT Meyerhof, respectively. The resistance factors are affected primarily by the ability of the pile cap to re-distribute the forces upon failure of one pile or more within the group.