Probabilistic Vulnerability Assessment of Horizontally Curved Multiframe RC Box-Girder Highway Bridges

Abstract

Numerous concrete box-girder bridges in California are horizontally curved and also have at least one in-span hinge. The curvature and in-span hinges in multiframe bridges lead to significant differences in bridge dynamic response during seismic excitations. In this article, a set of analytical fragility curves for horizontally curved highway bridges are developed based on nonlinear time history analyses in OpenSEES, focusing on subclasses of seismically designed multiframe concrete box-girder bridges with multicolumn bents and seat type abutments. Component damage levels are explored for joint seals, columns, bearings, abutments, unseating of decks, foundations, and shear keys, and system level damage states consistent with HAZUS-MH definitions. Curvature was identified to be an important factor that adversely affects the fragility of multiframe bridges. Median value modification factors are proposed to scale fragility curves to account for the deck radius effects.