Laboratory investigation of effect of Flat Submerged vanes on Scour at bridge Piers group and Abutment

Local scour involves removal of material from around piers and abutments as the flow accelerates around the obstructed flow area. Various methods have been suggested for the control and reduction of local scour around the bridge piers and abutment. Using submerged vanes is one of these methods. Vanes change the regime of bed load movement that led to control place of deposition and erosion. The function of vanes to reduce scour around the bridge piers and sediment movement in the region of vanes due to down flow in front of them are affected by arrays of the vanes. In the present study, Different lay out of arrangements (Parallel rows, two parallel rows, and two zigzag rows) Flat Submerged vanes with the ratio of length to height at an angle of 20 degrees relative to the direction of flow on protection of local scour around abutment and piers group with rectangular debris were laboratory investigation. All experiments conducted in uniform flow with clear water were be done. The results showed that the zigzag arrangement of the two three rows had the greatest effect to protection of local scour around abutment. In this case, vane distance from abutment and the row spacing with the relative spacing is 0/5 and 1.(The distance of the vanes from the abutment was La and the distance of the rows was 2La) that reduced the scour depth by 81%.