Author(s): Taeksang Kim; Mamoon Kareem; Ries Plescher; Mohammed Alshamlan; Adna Mohamed Saed; Daniel Che; Kevin White And Jeremy Bricker
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Keywords: Culvert scour Riprap design Sand bed saturation Hydraulic experiment Infrastructure stability
Abstract: Scour, the erosion of sediment around hydraulic structures, presents significant threats to the stability and safety of infrastructure, such as bridges and culverts. This study investigates the effects of sand bed saturation and culvert diameter on the required riprap length to mitigate culvert outlet scour. Experimental values, converted to prototype scale using Froude similarity, were used to establish linear regression models. The slopes of these models, reflecting the sensitivity of required riprap length to mitigate flow velocity at the culvert outlet, reveal notable differences between saturated and unsaturated conditions. Saturated sand beds exhibit steeper slopes, indicating a significant increase in riprap length with increasing flow velocity. In contrast, unsaturated sand beds show a more gradual increase, allowing for a more conservative riprap design. Additionally, larger culvert diameters require more substantial increases in riprap length, particularly under saturated conditions. This study underscores the critical importance of considering sand saturation and culvert diameter in designing effective riprap installations to ensure the stability and reliability of hydraulic structures.
Year: 2025