Evaluation of Effect of the Submerged Vanes and Slot on Reduction of Local Scour Around Bridge

The past research has shown that many methods have been used to reduce the scouring around piers. But the use of submerged vanes and slots has not been considered. In this research assemble of double submerged vanes with various lengths and angles attack on pier scouring reduction were carried out.. The submerged vanes were placed in four different positions (S1 to S4) relative to the pier head. The pier diameter was D=3 cm and the vanes length to the pier diameter ratio were: L/D= 0.33, 0.66 and 1. The angles of double vanes were 10,20,30,90 degrees corresponding to the flow direction. All tests were conducted on slot piers. The ration of width and height slots to pier diameter were 0.25 and 2 respectively. The results showed that using the slot pier can reduce the pier scouring about 21% , with submerged vanes with slot can be more effective for reduction of pier scouring. S1 and S3 positions showed best results in reducing the maximum scour depth compared to other positions. The maximum reduction of scouring was 86% in the third position (S3) when the length of vanes were 2 cm , and angles of double vanes were 10, 30, degrees corresponding to the flow direction.