Physical Modelling of Pier Scour in a Constricting Channel

Abstract

Experiments were completed in order to examine the effects of combined constriction and pier scour. Scour is cited as being a leading cause of bridge failure. It was found that in cases where both constriction and pier scour are present, the sum is greater than the linear addition of each individual case. This is contrary to the current industry assumption which states that the total depth of scour is the linear sum of the constriction and pier scour depth.

Velocimetry and scour data were collected enabling comparisons to be made in order to determine how the flowfield influences the equilibrium scour conditions. In addition, experiments were performed examining the effect that the pier shape has on the scour depth and distribution.

Since the results are contrary to the assumption used in industry, they are especially important and may help reduce future bridge failures.