Lifecycle Multihazard Framework for Assessing Flood Scour and Earthquake Effects on Bridge Failure

Abstract

A lifecycle multihazard framework is proposed to assess the system failure of bridge structures subjected to the combined hazards of flood-induced scour and earthquakes. The framework consists of three major components, including the conjunct use of probabilistic seismic and flood-induced scour analysis, nonlinear model pushover-based soil-foundation-bridge simulation, and multihazard failure analysis. Based on a case study for a simple bridge system considering a design life of 75 years, the results show that scour effects are varying with time. During the first 45 service years of the bridge, scour has insignificant effect on modifying the seismic vulnerability of the bridge in terms of two levels of system failures (i.e., extensive system damage or system collapse). After 65 years, scour dominates the cause to system failure, and between 45 and 65 years, bridge scour and earthquakes jointly contribute to system failure. This result implies that a time-sensitive assessment approach is necessary for managing aging bridges serving both seismicity- and flooding-active regions.