Vulnerability assessment of steel box girder bridge subjected to earthquakes

Fragility analysis for bridge is essential for damage assessment of transportation networks exposed to seismic hazards. The bridge harm due to the earthquake hugely have an effect on the transportation systems. Many such bridges were designed with previous regulation codes. Box girder bridge is the maximum not unusual shape in present time in highway bridge in addition to metro line. Such structures are a balanced cantilever or a span-with the aid of-span construction. Past outcomes indicate that the seismic ground motion damage the girder and piers and crucial for longer bridges. This study analytically determines the seismic fragility of a box girder bridge. A set of 10 excitation records of ground motion considering is applied for nonlinear dynamic analysis of the bridge. A 3-D finite element model is employed during this have a look at considering nonlinearity in the bridge piers. The element fragility curves are developed for different damage states to assess the severity of ground motions and to judge the vulnerable part of the bridge. Pga is taken as the ground motion intensity measure and the drift ratio and base shear was selected as the engineering demand parameter. The acquired fragility curves found out one-of-a-kind styles for the chance of exceeding mild to intense harm for the studied bridges. While the distinction among the chances of exceeding mild and intense damage withinside the shortest bridge turned into significant, withinside the tallest bridge it turned into negligible. The bridge chance of exceeding mild to intense damage state are compared.