chapter  2
33 Pages

Basic concepts

WithG.J.C.M. Hoffmans, H.J. Verheij

Hydraulic structures cause disturbances in uniform flow and sediment transport. Bed protection is constructed in order to decrease the maximum scour hole and to shift the scour holes that involve a potential risk to structural stability to a greater distance from the hydraulic structure. To ensure the safety and long term functioning of hydraulic structures, it is necessary to consider information with respect to failure mechanisms, boundary conditions and design criteria. In order to design hydraulic structures, loading and strength parameters have to be specified. An ice cover can divert the flow to the part of the bed near the hydraulic structure, resulting in an additional increase of local scour. Placing a bed protection downstream or around hydraulic structures is a common method of local scour protection. To produce a safe and reliable design, the total reliability as a function of all modes of failure should be approximated, at least at a conceptual level.