Integral abutment bridges (IABs) have performed successfully for decades and have demonstrated advantages over traditional, jointed bridges with respect to first cost, maintenance costs and service life. However, accurate prediction of IAB response to loading is complex and challenging; behavior is typically nonlinear due to the combined influence of thermal and long-term, time-dependent effects. Summarized herein are measured and computational results from examination of four interstate highway IABs located in central Pennsylvania. The collected data indicates that current AASHTO prediction methods are very conservative with respect to displacements. New computational models are used to perform a parametric study that considers the effects of seasonal thermal loading, thermal gradient, time-dependent material effects, abutment-backfill interaction and pile-soil interaction on deformations that occur over a 75-year bridge life. The measured and parametric study results provide a basis to establish an approximate method for predicting (1) maximum abutment displacement, (2) maximum bridge bending moments and (3) maximum pile moments over the bridge life.
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