Investigation of Square Collar application in Reduction of Local Scour around Bridge Piers

Scouring is defined as a natural phenomenon caused by the flow of water in rivers and streams. It is the consequence of the erosive action of flowing water, which removes and erodes material from the vicinity of bridge piers. Experiments were carried out in a flume that its length, width and depth were 10, 0.3 and0.5 meter, respectively. The pier diameter was 25mm and d50  0.8mm. To investigation of the collar effect used from three different sizes of square collar with  1.5 , 2 ,2.5 D W ( D : pier diameter andW : width of square collar) that are located in two different heights into the bed surface with  0.4 , 0 D Z . The results showed that installation of 2.5D collar under the bed can reduce scour depth approximately 70%. This reduction is up to 20% and 40% for 1.5D and 2D collars, respectively

کلیدواژه ها:

Scouring ، Square collar ، Bridge pier