Centrifuge Modeling of Pile Pinning Effects

Earthquake-induced deformation of piled bridge abutments in approach embankments underlain by liquefied soils may be reduced by the restraining forces provided by the piles and bridge superstructure. Design methods accounting for these "pinning" effects have been applied in practice, but they lack significant comparison with actual physical data. Three dynamic centrifuge model tests were performed to investigate pile pinning effects, and the results are presented in this paper. The centrifuge models were composed of two identical embankments underlain by liquefiable soil, one with a pile group and another without. Data from the tests demonstrated that the embankment with a pile group had less lateral movement and settlement than the embankment without a pile group. The experimental results and back-calculated stress-strain responses are described, and the implications for design practice discussed.