LOCAL SCOUR AROUND BRIDGE ABUTMENTS

1 INTRODUCTION The protrusion of a bridge abutment or a spur dike into the main channel creates a disturbance and obstruction to the otherwise equilibrium state of sediment transportation in an alluvial river. The flow accelerates and separates at the upstream face of the abutment as it moves past the obstacle, creating a vortex trail that moves downstream in a direction approximately perpendicular to the structure. The result is that the bed around the structure is eroded locally. The l…

LOCAL SCOUR AROUND BRIDGE ABUTMENTS

This paper summarizes the design equations for local scour depth around bridge abutments as proposed by different investigators, and also the different factors, affecting the scour depth. Methods for the estimation of local scour depth based on dimensional analysis are also presented. The design methods based on empirical relations such as flow depth, flow intensity, sediment characteristics, abutments shape and size, alignment, and approach channel geometry are also discussed. Since clear-water scour is the maximum scour depth, the equation for clear-water scour is recommended for the computation of local scour depth around bridge abutments for uniformly and non- uniformly graded sediments.