Local scour around bridge abutments in alluvial channels is an unavoidable problem. Accurate prediction of the scour hole depth and pattern is essential for a safe and economic design of bridge foundation. The local scour pattern around bridge abutments depends on the abutment shape, local flow field and type and properties of the erodible bed material. The current experimental study is carried out to investigate the local scour around vertical bridge abutments in sandy soils and to estimate the local scour pattern formed around the bridge abutment at equilibrium condition. In the laboratorial experimentations of the present study vertical wall abutment is used with three different sizes. Twenty four laboratorial experiments are carried out with flow parameters achieving clear water scour conditions using sandy soil as erodible medium. From the experimental results, empirical formulas are developed for sandy soil to predict the equilibrium scour pattern around vertical bridge abutment (equilibrium scour depth and scour width) in terms of the dominating factors that affect and control scour process (Froude number and vertical-wall abutments dimensions). |
