Effect of Mutual Interference of Bridge Piers on Scouring in Meandering Channel

Local scour is the reduction of original bed level around any hydraulicstructure. Bridge failure due to scouring has made researchers study thecause of scouring and predict the scour depth and pattern around bridgepiers and foundations. Several investigators have extensively studiedlocal scour around isolated bridge pier, but modern designs of the bridgescomprise of wide span and thus group of piers rather than a single pier. Theflow and scour pattern around group of piers are different from the case of asingle pier due to the interaction effect. The objective of present study is toinvestigate the effect of mutual interference of bridge piers on local scourexperimentally around two piers in non-cohesive bed. Experiments werecarried out on model bridge piers of circular cross section in a meanderingchannel. It was observed that when front and rear piers were placed at anangular displacement of θ = 40° and 80° respectively, maximum depth ofscour is maximum. Here θ is the angle the line drawn at the inlet of bend tothe line joining the centre of curvature and any point on the outer portion ofthe bend.