PREDICTION OF LIVE-BED SCOUR AT BRIDGE ABUTMENTS

A semi-empirical analysis on the time-averaged equilibrium live-bed sc our at an abutment, placed perpendicular to the flow direction, is pre sented. The approach is based on the flow and sediment mass continuity equations, scout geometry, flow resistance, and a generalized bed-loa d transport relation in an alluvial channel. The proposed equation can be reduced to the equilibrium clear-water scour equation proposed ear lier by the first writer (Lim). A total of 111 live-bed scour data fro m various sources were analyzed and compared with the developed equati on. The agreement between the computed and measured data is acceptable .