Seismic Vulnerability Assessment of Skewed Concrete I-girder Bridges Considering Various Structural Systems

Abstract Variation in the type of structural system (bent-to-deck connection) not only significantly impacts the seismic performance of regular bridges but also adds complexity when skewness irregularity is involved. Previous studies have separately evaluated the impact of either the type of structural system or skewness on the vulnerability assessment of bridges. The present study examines, for the first time, the combined effects of structural systems and skew angles on the seismic response of multi-span reinforced concrete I-girder bridges. For this purpose, two prevalent superstructure systems, namely, multi-span simply supported and multi-span continuous, are considered. For each system, the boundary condition at superstructure-substructure interface is modeled assuming elastomeric bearings with steel dowels. In the case of the multi-span continuous system, two more commonly applied types of bent-to-deck connection are considered, including pinned connectivity and elastomeric bearings without steel dowels. To account for the irregularity, five skew angles ranging from 0° to 60° are also considered. Probabilistic seismic demand models are developed for key components, such as columns and bearings, and fragility curves are generated. It is observed that superstructure skewness may reduce the sensitivity of column response to variations in the structural bridge systems by up to six times compared to regular counterparts.