Design Model for Piles in Jointless Bridges

Abstract

Piles in integral abutment bridges (jointless bridges) are subjected to lateral movement due to thermal expansion and contraction of the superstructure. The reduction in vertical load‐carrying capacity of the piles due to lateral movement is an important parameter in designing the piles and in setting length limits for the jointless bridge. A simplified design method for analyzing piles in integral abutment bridges is presented. The model was developed from previous analytical models and observations of pile behavior. Two failure modes for a pile are examined: the slip mechanism, where the pile slips through the soil; and the lateral mechanism where the failure of the soil‐pile system is associated with lateral movement of the pile. Equations for determining the ultimate load for the pile for each mechanism are obtained. Results predicted by the simplified model are compared to results from a nonlinear finite element program and shown to be conservative with respect to the finite element model.