Updating HEC-18 Pier Scour Equations for Noncohesive Soils
A dataset of 594 bridge pier scour observations from two laboratory and three field studies was compiled. The dataset served as the testing ground for evaluating potential enhancements to the pier scour tools for noncohesive soils in Hydraulic Engineering Circular 18 (HEC-18). In the current (fifth) edition of HEC-18, there are two primary equations for pier scour in noncohesive soils. One is the general equation applicable to most situations, including clear water and live bed conditions. The second is a coarse bed material equation recommended only for use under clear water conditions with coarse bed materials. The objective of this research was to determine if the coarse bed materials equation could be used for conditions beyond those under which it is currently limited. A framework for evaluating the two equations was developed using qualitative and quantitative tools.
- FHWA Publication Number: HRT-16-045
- Publication Year: 2016