Assessment the Effect of Skewness and Number of Spans in Seismic Behavior of Bridges with Continuous Multiple Spans Using MPA

The seismic behavior of skewed bridges compared to straight bridges is not well recognized and need more study to investigate its unique behavior under seismic forces. Much more damage have seen from skewed bridges particularly when its deck rotates in the earthquake. Many causes are involved in this behavior such as columns and piers nonlinear deformation patterns. Through a Modal Pushover Analysis (MPA) we will assess the inelastic seismic behavior of reinforced concrete bridges those have skew-angled seattype abutments. The angle of skewness will change the seismic behavior of this kind of bridges and in this paper this change is explored with special attention. Maximum nonlinear displacement is sensitive to increase the number of spans and the skew angle of abutments and piers, but the amount of effects are up to number of spans and angle of skewness. This study showed that as the number of spans increases, the deck rotation responses at abutments will be deducted and the adverse effect of skew would subtracted in the bridge.