Investigation of local scour around group bridge pier with different shapes

This study is based on laboratory experiments for computing depth of local scour around group bridge pier, considering the effects of upstream flow conditions, size of pier, median size of bed material and spacing between bridge piers on the maximum scour depth and scour pattern around bridge piers. The study was conducted using a physical hydraulic model for bridge piers, operated under clear-water condition and using uniform cohesionless sand as bed material. Three different models of bridge piers, having different sizes were used for showing the effect of the size on the local scour. The diameter of upstream bridge piers (D1) was varied to 2, 4, 6, 8, and 10 cm, and diameter of downstream bridge piers (D2) 10 cm for all. The spacing (S) between the bridge piers was varied three times 20, 30, and 50 cm for all groups. This experimental study was conducted in order to assess the reduction of local scour around group of bridge piers. The results of comparison between the performances of group of bridge piers under different span lengths reveal that the scour depth increases with increasing span length. We hope that the results of the present study will benefit the designers and engineers.