An Evaluation Method For Large Drifting Object-bridge Collision During Tsunami

During the 2011 Great East Japan earthquake occurring at the North–East pacific region, serious secondary disasters caused by collision of drifting containers or ships occurred in various structures when tsunami came. Drifting objects including large ships and tankers come in and out of ports in Japan. Disaster deterioration caused by drifting objects during earthquake and tsunami has become another problem. In this study, it is assumed that a large drifting ship collides with a large-span bridge in the gulf line during a tsunami. To investigate the impact behavior of the bridge during collision, tsunami simulations and nonlinear dynamic finite element analyses of the whole bridge during collision are performed. Based on the collision force calculations, an approximate analytical method is proposed, and the maximum size of drifting object which can result in the collapse of the whole bridge structure is calculated using this method.