The Effect of Superstructure Curvature on the Seismic Performance of Box-Girder Bridges with In-Span Hinges

Curved bridges are commonly constructed at interchange routes as connectors between two main roads in a highway network. Although past earthquakes, particularly the 1971 San Fernando earthquake, revealed the susceptibility of curved bridges to experience considerable damage during earthquakes, the seismic performance of this bridge class has not been investigated thoroughly. To address a part of this deficiency, the current study concentrates on the seismic performance analysis of curved concrete box-girder bridges with in-span hinges. In this bridge class, common potential damage patterns include damage to bearings and expansion joints, which are the most vulnerable components of the system. Hence, curved bridges including, in-span hinges, require particular investigations. As a case study, a highly curved bridge constructed before 1971 and located in California is selected for seismic analysis in this paper. The bridge seismic response is evaluated by performing nonlinear time history analysis in OpenSees on the representative bridge model with two configurations: (i) with an in-span hinge, and (ii) without in-span hinge (i.e. continuous deck). Moreover, the effect of superstructure curvature is evaluated by varying the radius of curvature from low to high (a bridge with a high radius approaches a straight bridge configuration). The analysis results indicate that curvature significantly affects the seismic response of the considered bridge, particularly for the model which includes an in-span hinge.