Time to equilibrium scour at vertical-wall bridge abutments

Abstract

The main objective of this study was the definition of a predictor of time to equilibrium on the basis of experimental evidence. The study used the results of an important number of long-lasting experiments, run under clear-water flow conditions for large abutment lengths. These experiments have already been reported by the present authors in recently published papers. It is concluded that time to equilibrium scour at thin vertical-wall abutments, protruding at right angles from the side wall of fully developed, uniform flows in wide rectangular channels on flat bed of uniform non-ripple forming sand depends mostly on the relative abutment length. It can also be concluded that time to equilibrium may be rather large in the field. The main objective of this study was the definition of a predictor of time to equilibrium on the basis of experimental evidence. The study used the results of an important number of long-lasting experiments, run under clear-water flow conditions for large abutment lengths. These experiments have already been reported by the present authors in recently published papers. It is concluded that time to equilibrium scour at thin vertical-wall abutments, protruding at right angles from the side wall of fully developed, uniform flows in wide rectangular channels on flat bed of uniform non-ripple forming sand depends mostly on the relative abutment length. It can also be concluded that time to equilibrium may be rather large in the field.