SRICOS: Prediction of Scour Rate at Bridge Piers

This is a method to predict scour at bridges founded on soils and soft rocks. It was first developped to predict pier scour for a circular pier in deep water, then it was extended to cover complex pier cases (shape, angle of attack, wide pier effect, pier spacing), and then was further extended to include channel contraction scour. Work is planned to extend the method to include abutment scour, meander migration, and stream bed degradation in the future. The method consists of obtaining standard size soil or soft rock samples from the bridge site, testing them in the EFA (Erosion Function Apparatus) to measure the erodibility of the soil or soft rock, using that measurement to predict the scour depth versus time curve under a given hydrograph. This approach requires the use of a simple computer program called SRICOS. A simplified version of the SRICOS method can be performed on the back of an envelope for preliminary design purposes.