Evaluation of near-fault ground motions on seismic behavior of the movable folding bridges

Bridges are structures with great importance, and any interruption could cause financial damage and even life-endangering people's life. Based on the type of structure, bridges can be divided into conventional, cable, and movable bridges. Space limitations in urban areas and the establishment of the cities around the rivers attracted designers and engineers to these types of bridges. Considering the importance of the foldable bridges, seismic behavior of the bridge under subjection to near-fault ground motions has been investigated in this paper. Inheriting impulse effects in near-field contents is the main difference with far-field records. The total length of the bridge is 40 meters and consists of three movable spans, which are 3.65, 2.7 and 3.65 meters long. To study the seismic behavior of the bridge, at first modal analysis has been performed in ABAQUS built model and then under subjection to near-fault ground motions, which has been matched according to issue No.463 seismic time history analysis performed. The acceleration response, base shear, and vertical deflection of the bridge induced by perpendicular horizontal excitations were calculated and extracted. The destructive effect of the Varzeghan earthquake is more than other earthquakes, and the numerical value of acceleration response, vertical displacement, base shear, and tower drift is considerably higher than other earthquakes. The connection zone of the tower to the deck is vulnerable to seismic loads, and plastic hinges have been formed.