COMPARISON OF PREDICTION EQUATIONS FOR BRIDGE PIER AND ABUTMENT SCOUR

There are at least 10 prediction equations for bridge pier scour, and designers are often at a loss over which one to use. There are only three or four prediction equations for abutment scour, but these have not been highly publicized. The pier scour equations fall into three basic categories: those of the University of Iowa, those of the Colorado State University, and those based on foreign literature. The similariteis among the pier scour equations and the range of data on which they are based are shown. FHWA sponsored several studies during the 1970s aimed primarily at comparing field data with the various equations to show which ones best predicted local scour for U.S. streams. These studies were somewhat inconclusive because of the many interrelated variables in the scour process, but they do show which equations are conservative and which are not. (Author)