Bed topography variations in bend by simultaneous installation of submerged vanes and single bridge pier

Abstract

Every year, thousands of bridges around the world are destroyed by scouring around their piers. One of the methods to control and protect the piers against scouring is to use submerged vanes. The purpose of this paper is to investigate the effect of upstream submerged vanes on scouring around the bridge pier and bed topography changes. For doing experiments, a cylindrical bridge pier and several numbers of submerged vanes with various angles and lengths were used in a laboratory flume with a 180° sharp bend. The results illustrate that by using three submerged vanes, sediments have progressed less toward the downstream. Moreover, the surrounded rectangle on scour hole around the bridge pier has the largest and smallest dimensions in test with four submerged vanes, length of 1.5 times the pier diameter and angle of 35° relative to the tangent at the bend mid-section, and in a test with two submerged vanes, length of equal to the pier diameter, and angle of 15°, respectively.