Errors in Design Leading to Pile Failures During Seismic Liquefaction

Collapse of piled foundations in liquefiable soils has been observed in the majority of the recent strong earthquakes despite the fact that a large margin of safety is employed in their design. This paper critically reviews the current design methods and the underlying mechanism behind them. The current method of pile design under earthquake loading is based on a bending mechanism where the inertia and slope movement (lateral spreading) induce bending in the pile. This paper shows that this hypothesis of pile failure cannot explain some observations of pile failure. It has been identified that the current design codes of practice for pile design omit considerations necessary to avoid buckling of piles due to the loss of lateral soil support in the event of soil liquefaction, i.e. the structural nature of the pile is overlooked. A new design approach is proposed in this paper taking into account buckling effects