Nonlinear Finite-Element Analysis of Integral Abutment Bridges due to Cyclic Thermal Changes

Abstract

This paper introduces a finite-element (FE) investigation into the behavior of integral abutment bridges (IABs) under alternate cycles of expansion and contraction of the bridge due to seasonal temperature variations. As an example, a multiple-span, reinforced concrete, solid-slab bridge was proposed and analyzed using an elastoplastic two-dimensional FE model. The bridge abutment is supported on steel H-piles. The proposed FE model has the capability of simulating both the construction of the bridge and the backfilling process using a multistage numerical technique. The mobilized earth pressures and changes in these pressures due to thermal effects were predicted for different bridge lengths. The results of the analyses showed that the design earth pressures are notably affected by the bridge length, the number of temperature-increase cycles, and the stiffness of the backfill material, but to a lesser extent by the relative stiffness between the bridge deck and abutment. The pressure distributions predicted here may be useful when updating the current IAB design guidelines.