Sensitivity analysis and optimization of pier shape scour prediction using HEC-RAS

Abstract Scour around bridge piers threatens bridge stability. This study uses the Hydrologic Engineering Center River Analysis System to improve depth estimates for various pier shapes. The Colorado State University and Froehlich equations were tested with a one-dimensional model calibrated for circular, square, rectangular, oblong, oval, and cylindrical piers. Sensitivity analysis identified coefficients K2, K3, flow velocity, and depth as key factors, with K2 being most significant. The Colorado State University equation overestimated scour depths, especially for square piers. The Froehlich method provided more accurate predictions, confirming the system's value in hydraulic modeling for bridge stability analysis.