A heretofore overlooked mechanism is described for the removal of sediment in the vicinity of a structure, such as a bridge pier, located in erodible sediment and subjected to water flow. The strength of this mechanism depends on, among other things, the ratio of structure width to sediment grain size, b/D50. The mechanism results from the pressure gradient field imposed on the bed by the mean flow around the structure. The large pressure gradients created by the structure are confined to a relatively narrow region near the structure. The forces due to the pressure gradients acting on the sediment grains near the structure decrease with increasing values of b/D50. This mechanism helps explain the functional dependence of equilibrium local scour depth on b/D50 observed in both laboratory and field tests. It also explains why, in general, physical model local scour tests tend to overpredict prototype scour depths.


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    Title :

    Overlooked Local Sediment Scour Mechanism


    Additional title:

    Transportation Research Record


    Contributors:


    Publication date :

    2004-01-01




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English




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