Home Magazines Editors-in-Chief FAQs Contact Us

A novel method for riprap design of scour protection at bridge piers


MOJ Civil Engineering
Youssef I Hafez
Yanbu University College, Saudi Arabia

Abstract

A novel method is developed for riprap design of scour protection at bridge piers. The method is based on the assumption that the minimum stable riprap size exists when the work done due to the attacking vertical flow jet upstream of the bridge pier is no longer capable to lift the protecting riprap particles out of the scour hole. The developed equation expresses the minimum particle size as a function of the longitudinal velocity just upstream of the pier, the flow depth, the bed material/riprap specific gravity, and the pier width. The proposed equation has the advantages that it is theoretically based which allows adding wave and seismic forces in addition to the already considered hydrodynamic forces, it includes effects of pier width, it determines bed armoring, and it gives the equilibrium minimum riprap size while previous methods give the median size D50.

Keywords

riprap design, bridge piers, mathematical modeling, scour holes, energy transfer/balance theory, bed armoring, wave forces, seismic forces

Testimonials