Horizontally curved steel bridge seismic vulnerability assessment

Most computational research related to steel bridge seismic vulnerability has focused on statistical extrapolation of analysis results for individual straight bridges. However, there has been a steady growth in the use of horizontally curved steel bridges in highways and interchanges in large urban regions. Given the large number of curved steel bridge structures in use in the US and abroad, with some of those structures being located in seismic zones, the feasibility of examining the effects of curvature on bridge vulnerability should be investigated. In this study, the seismic performance characteristics of an existing inventory of horizontally curved, steel, I-girder bridges located in Pennsylvania, New York, and Maryland were used to generate fragility curves. Representative fragility curves for horizontally curved, steel, I-girder bridges were estimated using Response Surface Metamodels (RSMs) in conjunction with Monte Carlo simulation. The methodology was used to construct fragility curves for select bridge components (bearings, columns and abutments). The curves were generated for four different, preexisting, performance states that represented slight, moderate, extensive, and complete damage under varying levels of earthquake intensity. The generated fragility curves provided information related to seismic response of the bridge inventory that was investigated, such as radial deformations at the bearings being the most susceptible component to seismic loads.