Experimental study of scour around bridge piers of different arrangements with same aspect ratio

Abstract

Scour around bridge piers is a challenging problem faced by bridge engineers. Scour is caused by the horse-shoe vortex formed due to the presence of the pier obstructing the flow. The behaviour of horse-shoe vortex differs according to the arrangement of piers. The flow pattern is different for a group of piers and a solid pier thereby creating different scour patterns. In this paper, the scour around bridge piers of different arrangements with same aspect ratio is investigated in a laboratory flume. All three arrangements studied have an aspect ratio (L/B) of 5.The experimental flume is 7.5m long,0.3m wide and 0.6m deep with a re-circulating facility. The results obtained showed that scour volume is considerably reduced around a single solid pier compared to the combinations of piers. Further, the flow field becomes complex due to the combination of piers.