EXPERIMENTAL STUDY OF BRIDGE PIER SHAPE TO MINIMIZE LOCAL SCOUR

The study of local scour around bridge piers is very important for safe design of piers and other hydraulic structures. In this study, shape of pier is the main concern with three different velocities (0.18, 0.25, and 0.3) m/sec and other parameters like flow depth, bed material and etc. are remain same for all experiments. The experiments were conducted using laboratory flume, operated under the clear water condition using sand as a bed material. The test program was done on ten different shapes, Circular, Rectangular, Octagonal, Chamfered, Hexagonal, Elliptical, Sharp, Joukowsky, Oblong, streamline. were used to investigate the effect of the bridge pier's shape on local scour to conclude the optimal shape that gives minimum depth of scour. Comparison of results show that scour at upstream is directly proportional to exposed area of upstream nose of pier. The results showed that the rectangular pier gives the largest scour depth (7.6) cm, while the streamline shape gives the lowest scour depth (3) cm. The equilibrium scour depth of pier models compared with theoretical equations has been developed by some researchers and the results were very close.