Mohammad Khanmohammadi - Assistant professor at the school of civil engineering University of Tehran,
Mohammad Jafarkarimi - Student of structural engineering at the University of Tehran,

The unusual behavior of the skewed bridges under seismic loads, has led different researchers to focus more on their behavior in recent years. The angle created by the axis of the bridge’s support and the line normal to the road line, excites some of the bridge’s modes of vibrations other than the modes that are usually stimulated in normal bridges. This seems to be the reason for the skewed bridges unusual behavior. Besides, the horizontally curved bridges, have more complicated behavior than the normal bridges because of their curvature. The research that have been conducted on predicting the behavior of the horizontally curved bridges, seem to be insufficient and limited. In this research, efforts has been made to study the seismic behavior of the horizontally curved skewed RC bridges, in order to determine the suitable angle of applying the seismic load to obtain the maximum responses. Effect of modeling the abutment on the behavior of the bridges was studied as well. In this study, the linear response-spectrum analysis have been conducted on the models. To determine the suitable angle of applying the seismic load to obtain the maximum responses, the seismic load has been applied to the models in various angles. Results show that in the majority of the models that were created in this study, the maximum responses are obtained by applying the seismic load either at the principal directions of the bridge (the road line and perpendicular to that) or at the direction of the abutments.

RC bridge, Skewed bridges, Horizontally curved bridges, Skew angle