Effect of Skew Angle on Seismic Response of Irregular Concrete Bridges with Horizontal Curve

This article is a parametric study of 315 reinforced concrete bridges including 45 straight and 270 curved bridges for different geometrical conditions in different layouts, which were stimulated by earthquake near-field records. Past experiences show that irregular bridges with skew angles exhibit more critical behavior when exposed to near-field records. For this reason, in current research the effect of parameters such as skew angle (alpha), degree of the curvature (beta) and irregularity obtained for different ratios of the height of the middle columns of the bridge in three different layouts on the seismic performance of the bridge has been investigated by performing non-linear time history analysis. Bridges in all modeling types are designed according to AASHTO standard criteria. The results of different modeling types are compared with the base model (regular bridge without curvature and zero skew angle). The results show that the seismic behavior of the bridge is strongly influenced by the skew angle of the bridge deck and bridge curvature. It was also observed that the rate of impact of changes in the skew angle of the bridge compared to the changes in the curvature of the bridge and irregularity is more noticeable to change the seismic responses of the bridge. If it is necessary to build curved bridges, in order to avoid the occurrence of torsional breakage in the bridge columns, it is recommended that the curvature angle should be considered equal to 40 degrees at most, and even if possible, it is recommended to avoid building bridges with skew angle of more than 30 degrees.