Abstract
Very heavy rain on July 28th in 2013 in Yamaguchi and Shimane prefectures resulted in severe damages of railway bridges in the Abu river. To evaluate the water preressure induced in the bridges, we conducted numerical analysis using the Smoothed Paricle Hydradynamic Method. The numerical result shows that the heading up of the water flow induces the gap height between the front face and back face of the bridge pier. It can be found that these gaps cause the unbalance of the static water pressure and increase the bending moment and shear force to the bridge pier. We finaly proposed the equation of shear force and bending moment estimated from the gap height of water surface.
