Abstract
Detour flow around a bridge causes floods and bank erosions every year all over the world. However, the flow and the bank erosion characteristics of detour flow around a bridge are not studied well, as a result, the countermeasures for the detour flow are not taken well to design levees and bridges. In this study, the flow and bank erosion characteristics of detour flow around a bridge are discussed by using plane two dimensional bed deformation analysis. The results show that the non-dimensional shear stress at the top edge of a levee in the downstream area of the bridge is large, because the detour water flow back to the main channel there. As a result, the bank erosion is initiated there. Subsequently, the road connecting to a bridge suppresses the progress of the bank erosion to the upstream of a bridge. Additionally, the bank erosion in the downstream of the bridge is also suppressed.
