Scour around wide piers in shallow water

The assessment of pier scour at many bridges is a difficult task because of the numerous complexities of the scour process. One of these complexities occurs when the flow depth is shallow relative to the pier width. A preliminary examination of the effect of wide piers in shallow water is provided and a modification or correction factor for currently used scour equations to account for this effect is developed. An experiment was conducted to test the effect of shallow flow depths and wide piers while keeping all other variables constant. Existing laboratory data along with data from the study were analyzed to incorporate the effects of wide piers on the scour at bridge piers. During the study regions of relative flow depth (flow depth-to-pier width ratio) at which the scour process differs were determined. The definitions of wide piers and shallow flow in terms of the relative depth to pier width were established.