Prediction of Scour at Bridge Pier Foundations Founded on Rock and Other Earth Materials

The erodibility index method, which can be used to predict scour thresholds for rock and other earth materials, is described. The scour threshold is defined by a relationship between the erodibility index and stream power that is based on analysis of field and laboratory data. An explanation of how the method is applied to calculate scour depth is presented, followed by a case study to calculate bridge pier scour.