The Study of Riprap as Scour Protection for Bridge Abutments

The purpose of this paper is to provide design guidelines for riprap protection of spill-through and vertical-wall abutments situated in floodplains. With the benefit of laboratory experiments, empirical design guidelines are provided for the protection of bridge abutments for a broad range of encroachment on the floodplain. The results of this study are presented as design equations and velocity correction factors for the respective abutment type. Guidance is provided for determining the appropriate average velocities to be implemented in the design equations. The results presented in this paper are published in the Federal Highway Administration publication, `Evaluating Scour at Bridges,' Hydraulic Engineering Circular No. 18.