Incorporating Soil Erodibility Properties into Scour Risk-Assessment Tools Using HYRISK

AbstractScouring around foundations is the most common cause of bridge failures. Scour risk assessment tools allow engineers to better quantify risks associated with existing bridge infrastructure. However, the majority of these tools, including HYRISK, do not incorporate soil property information. This paper develops an approach that associates the critical shear stress of a soil to its Unified Soil Classification System (USCS) soil group classification. This approach is applied to approximately 40 bridges in Georgia using HYRISK and shows how incorporating soil property information changes the expected financial losses associated with a bridge failure. This is important because it enables engineers to use soil property information that is commonly found on boring logs to direct limited maintenance funds to those bridges that are most at risk to scour failure.

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