Effect of Soil Stress History on Scour Evaluation of Pile-Supported Bridges

Abstract

Scour is a major cause of bridge failures, and the Federal Highway Administration (FHWA) now mandates that states assess the susceptibility of their bridge inventory to scour. The authors have developed and described an integrated analysis program (IAP) that allows the user to accurately approximate nonlinear soil behavior around pile foundations within a structural analysis model. This paper describes a study performed to examine the influence of soil stress history on the outcome of a scour susceptibility analysis. Twenty-two models including the superstructure, substructure, and soil reactions were examined in which scour depth, soil type, and inclusion of soil stress history effects were varied. It was found that the stress history of soils had a limited effect on the performance of the bridge analyzed. This result was found to be in contrast to prior findings from studies performed on isolated piles, indicating that performing an integrated-type analysis is key to obtaining an accurate assessment of bridge scour susceptibility.