Abutment scour at the relief bridge placed in a flood plain

Abstract

This paper presents an experimental analysis of the scour processes that take place close to the abutments of relief bridges, placed in roads crossing flood plains, whose main characteristics are like the ones of the Paraná River Valley (Argentina). The immediate background on this subject has suggested that the presence of such scours produce a discharge redistribution across the section where the bridge is placed. This fact is the basis of the main hypothesis of the present research, which proposes that the discharge redistribution interacts with the local abutment scour. The good fitting achieved by experimental data to the functional relations proposed ratifies the initial hypotheses. It has been demonstrated that local scours in relief bridge abutments depend on initial flow conditions, velocity and depth adjacent to the abutment, as well as on the process of flow redistribution that takes place during their development. This last phenomenon was adequately evaluated by the incorporation of the bridge width, a variable that characterizes the whole process as a typical plant phenomenon.