Experimental Study of Local Scour Downstream of Cylindrical Bridge Piers.

Scour is a natural phenomenon caused by the erosive action of flowing stream on alluvial beds, which removes the sediment around or near structures located in flowing water. It means the lowering of the riverbed level by water erosions, such that there is a tendency to expose the foundations of a structure. It is the result of the erosive action of flowing water, excavating and carrying away material from the bed and banks of streams and from around the piers of bridges. The failure of bridges due to excessive local scour during floods poses a challenging problem to hydraulic engineers. The failure of bridge piers is due to many reasons, such as localized scour combined with general riverbed degradation. In this paper, we tried to estimate the temporal variation of scour depth at non-uniform cylindrical bridge pier, by an experimental work carried out in the civil engineering hydraulic laboratories of Gaziantep University on a channel with dimensions of 8.3m length, 0.8m width and 0.9m depth. Experiments have been carried out at 20 cm depth of a sediment layer with d50=0.4 mm. Three bridge pier shapes having different scaled models have been constructed in a 1.5m test section in the channel. [ABSTRACT FROM AUTHOR]