Author(s): S. M. Borghei; S. M. Bateni; M. M. Hoseini
Linked Author(s):
Keywords: Local scour; Bridge pier; Experimental test; Collar
Abstract: The stability of bridge piers in rivers and streams very much depends on controlling local scour. Many attempts have been done to have a better understanding of the scouring phenomena and the control concepts. Laboratory experiments are very popular, as well as being effective, to try different methods of scour control. One of the methods would be use of collars (horizontal plates) around the piers, where, the geometry and position of such a structure can be found from experimental tests. In this study, different ratios of circular collar diameter to circular piers diameter (B/b) in clear water have been tested. Initially, to calibrate the experimental setup, the scour without any collar was measured and checked with the Melville and Sutherland’s proposed results. Then, scour with different collar sizes at different levels above and beneath the bed surface were tested. The results show that the position of the collar at 0.2Y below the bed (Y is the water depth) has the most scouring control effect, while the size of the collar is of second order of importance. Finally, the optimum geometry of collar is suggested.
Year: 2004