عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Large woody debris is transported and accumulated in front of piers by floods which increases the scour around the bridge piers and it may cause the bridge failure. In this study, the effect of woody debris accumulation on the scour around a circular pier installed on the pile cap was experimentally investigated. The experiments were performed under clear water condition with two discharges of 30 and 40 L s-1 with and without debris accumulation in front of the pier for different sizes of the woody debris. The results showed that in the case of no debris accumulation, the scour around the circular pier with pile cap was 80% less than that around the pier without pile cap. The existence of the debris in front of a pier with pile cap significantly increased the depth, width and length of the scour hole. The accumulation of this debris could increase the scour depth 12-14 times as compared with the case of no debris. In addition, a new equation was presented using dimensional analysis for prediction of the maximum scour depth in the existence of debris accumulation in front of a circular pier.