Effect of Submerged Vanes on Scour Around a Bridge Abutment

Abstract

Submerged vanes are small plate structures that create a secondary flow rotation to reduce scouring. This paper presents the results of laboratory experiments investigating how submerged vanes affect scouring around a vertical wall and spill-through abutments under clear water conditions. This study focused on vane distance from the abutment, lateral spacing of the vanes, number of vanes in a row, number of vane rows, the angle of attack with flow, the direction of the vanes, and the position of the first vane relative to the toe of the abutment. An angle of 30o was found to be the best angle of attack and lateral spacing of vanes obtained 2H S - 3H S . In addition the optimal distance of the first vane from the toe and wall of the abutment was L/3 and B/3.2, respectively (in which L is the abutment length and B is the channel width), and the number of vanes in a row was found to be 1 and 2. These results showed that, the maximum scour reduction in a vertical wall and spill-through abutments was 34.2% and 35.6%, respectively. Based on experimental results from changing the direction of the vanes and locating the first vane along the toe of the abutment, the depth of the scour was increased.