Seismic-induced collapse simulation of bridges using simple implicit dynamic analysis

A simple implicit dynamic analysis method is extended to simulate the seismic-induced collapse of bridges. Nonlinear and discontinuous behaviors, such as material yielding and cracking, member damage, separation, falling and collision with other members, are considered in the analysis. An impact model with a contact detection scheme is developed to consider the impact response between beam elements representing bridge superstructures. Multiple-support excitation is considered. The Matsurube Bridge which collapsed in the 2008 Japan Iwate-Miyagi inland earthquake due to not only strong ground excitations but also the sliding of the rock mass beneath the bridge is analyzed for verifying the effectiveness of the analysis method. By reproducing the in-situ collapse situation, the failure mechanisms of the bridge are estimated. The results demonstrate that the simple implicit dynamic analysis is robust in simulating the collapse of bridges that exhibit highly nonlinear and discontinuous behaviors under extreme earthquakes.