Estimation of Scour Depth at Bridge Piers by Using FASTER Model and Experimental Formulas

Bridges are one of the most important river structures. One of the main causes of bridge failure is local scour at bridge piers. Yearly, Many bridges failed around the world because of disregarding hydraulic factors. Hence, an accurate prediction of scour depth at piers is essential for the safe design of the bridge foundation. In this study, local scour at Aala Bridge (Ramhormoz) is investigated. The Aala Bridge crosses the Aala River near the city of Ramhormoz, Khuzestan province. We use one dimensional Saint-Venant Equation for simulation at river dynamic in FASTER model. For evaluation of scour depth, 14 scour equations in subroutines were added to FASTER model. Comparison between computed scour depth showed that equation of Froehlich (1996) appear to give a reasonable estimate of the local scour depth. Jain and Fisher equation (1979), Melville equation (1997) and Melville and Sutherland equation (1988) overestimate scour depth, and the other experimental equations are not suitable for this condition.