Numerical Study of Road Embankment Type Action on Shear Stress Around Skewed Bridge Abutment

Abstract

This paper investigates the effect of different geometries of approach embankments and guides banks on the flow pattern and bed shear stress values in the skewed bridges in the compound channel using three-dimensional numerical modelling. First, the numerical model was evaluated based on the results of existing laboratory studies. After ensuring its proper performance, the elliptical guide bank and the three types of abutments: vertical-wall, spill-through, and wing-wall, at different skew angles are examined. Investigation of the values of maximum velocity and bed shear stress at the flow-conducting embankment and the flow-splitting embankment showed that in the flow-conducting embankment, the best performance is assigned to the elliptical guide bank. In contrast, the performance of various abutments is different for the flow-splitting embankment depending on the skew angle of the bridge. Then, different patterns based on streamlines for the geometry plan of the guide bank were proposed and studied. The results show that the most suitable pattern for the guide bank reduces the maximum flow velocity by up to 15% and reduces the maximum bed shear stress by up to 80% around the flow-splitting embankments.