Abstract
Many bridge girders were washed away by tsunami caused by the Great East Japan Earthquake 2011. Recently, the localized heavy rain causes some flood damages. Some bridge girders were washed away by flood same as tsunami. The hydraulic experiments and simulations were carried out on the assumption that water flow forces caused by tsunami and flood can be estimated as steady water flow forces of drag and lift. We focused on the drag force, and we studied about four types of steady water flows acting on a bridge girder.
