Coupled Field Monitoring and Structural Analysis to Assess Scour Conditions

Abstract

This paper reports on the implementation of a relatively novel scour monitoring system that includes the ability to record substructure response to potential changes in scour conditions. The substructure instrumentation consists of tilt sensors installed at the top of each of two in-water piers on an existing common configuration of a steel I-girder bridge that is currently the site of severe scour problems. The key focus of this paper is the structural analysis that was required to assess the significance of potential instrumentation readings resulting from these sensors. Two types of structural analysis were performed: a one-dimensional pushover analysis to assess substructure stability and a three-dimensional finite-element analysis to evaluate superstructure performance as a result of movement to the substructure. As a result, the substructure displacements corresponding to unfavorable performance of the structure were determined in both types of analysis. The effects of scour on the superstructure are also used to draw attention to the need for a greater understanding of the consequences of scour.