Analysis of Scour Depth Around Bridge Piers With Round Nose Shape by HEC-RAS 5.0.7 Software

Abstract

Local scour of bridge piers is the main reason for the failure of a hydraulic structure like abutment, bridge piers, etc. Local scours is a complex phenomenon that depends on the discharge, depth of flow, shapes of the pier and distribution of sediment particle. The problems of local scours occurred in Krueng Ineng river, Nagan Raya Regency will cause a structural collapse which has the impact of decreasing the stability of the bridge structure. In this study, the software of Hydrologic Engineering Center River Analysis System (HEC-RAS) 5.0.7 is used to evaluate local scour around the bridge pier which employs the Colorado State University method as a default equation. Flow conditions were simulated using HEC-RAS flow modeling software estimated for 100-year flood. The Results of the analysis with used the peak discharge (Qp100) that occurs in the Krueng Seunagan watershed is 1513m3/sec, pier width of Round Nose shape is 4m, and average grain size analysis D50 and D95 is 0.91mm and 4.35mm, show a maximum scour depth obtained is 5.04m. The results of this study will be a reference for the local government to planning appropriate handling for minimalizing local scours in the study area.