Abstract: “Scour is the formation of scour hole around the structure mounted on and embedded in erodible channel bed due to erosion of soil by flowing water. The formation of scour hole around the structures depends on the depth of flow, shape and size of slender structure, angle of attack of flow and sediment characteristics. The flow characteristics around these structures changes due to manmade obstruction in the natural flow path which changes the kinetic energy of the flow around these structure. Excessive scour affects the stability of the foundation of the structure by the removal of the bed material. The accurate estimation of scour depth around bridge pier is very difficult. The foundation of bridge piers have to be taken deeper and to provide sufficient anchorage length required for stability of the foundation. In the present study, scour depth is estimated around circular piers by HEC-RAS for a straight channel. The flow characteristics around these structures are presented for differe”

Keywords: Scour, Bridge pier, Pier shape, Horseshoe Vortex