Local scour around a model of the schoharie bridge pier was experimentally investigated in the laboratory. The tests simply focused on the effects of the angle of attack and flow velocity on the maximum depth of scour. Clear-water scour conditions prevailed, that is, the shear stress at the bottom in the upstream flow is always less than the critical value for beginning of sediment motion. The experimental results indicate that the effect of the angle of attack is related to the undisturbed flow froude number. In particular, the ratioof the measured scour depths for skewed and aligned piers decreaseswith increasing froude numbers. Velocity is found to have an important influence on scour depth. This paper appears in transportation research record no. 1319, bridge and hydrology research 1991.
Abstract