Experimental investigation of local scour around bridge pier groups

Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Civil Engineering, Turkey

Approval Date: 2013


Supervisor: ZAFER BOZKUŞ


It is an important task that design engineers in practice predict the local scour around bridge piers as accurately as possible because excessive local scour around bridge piers unbalance and demolish the bridges. Many equations have been proposed previously by various researchers, based on their experimental findings, but no general method has been developed so far due to the complexity of the topic. In the present study two new bridge pier groups were employed to investigate the inclination effect of the most upstream and downstream piers on the local scours around all piers. Total of 72 experiments have been conducted with 3 inclination angles, one of which representing the vertical case, each experiment lasting 6 hours, under uniform flow and clear-water conditions for a range of water depths and flow velocities on the uniform bed material. It is clearly observed and measured that the amount of local scour reduces substantially by the effect of inclination in the group piers, especially the reduction in the scour around the most upstream pier is found notable. Based on the experimental data, regression analyses are made and an empirical scour depth equation is developed for each individual pier in the pier groups studied. Comparisons with the similar studies performed by other researchers have been made and the results discussed.