Analytical Fragility Functions for Horizontally Curved Steel I-Girder Highway Bridges

Abstract

Horizontally curved bridges were investigated following a statistical evaluation of typical details commonly used in the United States. Both seismically and non-seismically designed bridges are considered where the primary differences are in column confinement, type of bearings and abutment support length. Columns and bearings were found to be the most seismically vulnerable components for both categories. Central angle was identified as an important factor that increases the demand on various components, particularly columns. Furthermore, larger angles lead to increased deformations at the supports which adversely affect the seismic vulnerability. Consistent with the fragility curves that account for the central angle explicitly, a second set of system fragility curves were introduced for cases when central angle is not specified such as the case in the National Bridge Inventory. Comparison of fragility parameters to those suggested by HAZUS-MH highlighted the need for revisions to account for current design practices and central angle.