Response sensitivity analyses of skewed bridges with and without considering soil–structure interaction

The seismic behavior of skewed bridges has not been well studied compared to straight bridges. Skewed bridges have shown extensive damage, especially due to deck rotation, shear-key failure, abutment unseating, and column-bent drift. This study, therefore, aims to study the behavior of skewed and straight highway overpass bridges both with and without taking into account the effects of Soil–Structure Interaction (SSI) due to near-fault ground motions. A set of nonlinear dynamic analyses was carried out using an intense pulse-like ground motion with two orthogonal components. The effect of the abutment skew angle on various demands was assessed. It was found that most of the demands were very sensitive when there was an increase in the skew angle. Deck rotation showed a higher sensitivity to the increase in skew angle; therefore, it postulated an increasing trend with respect to the increase in the skew angle. Adding SSI elements imposed a decreasing effect on various demands. Furthermore, various sensitivity analyses were carried out with respect to the change in site properties and skew angle and their effects on various demands were investigated. It was concluded that considering a performance-based approach, in which a higher number of ground motions is utilized, would be more useful to capture the sensitivity of various bridge responses with respect to change in different parameters. This would also provide a better intuition regarding any specific trend specifically with respect to the effect of change in skew angle on various demands for different site classes.