TY - JOUR T1 - Using Slot to Control and Reduce Local Scour at Round-nosed Rectangular Bridge Piers TT - کنترل و کاهش آب‌ شستگی موضعی در پایه‌های پل با مقاطع مستطیلی گرد گوشه با استفاده از شکاف JF - JCPP JO - JCPP VL - 7 IS - 3 UR - http://jcpp.iut.ac.ir/article-1-441-en.html Y1 - 2003 SP - 13 EP - 28 KW - Local scour KW - Bridge pier KW - Pier slot. N2 - The use of slot through a pier is a new method proposed to control local scour at bridge piers. In this study, control of local scour at bridge pier is studied using 20 pier models under clear water conditions. The models consist of one circular pier without slot, three round-nosed piers without slot, and 16 piers with slot. Two slot lengths were chosen (yl=b and yl=2b, where y1 is the length of slot and b is the width (diameter) of the pier). Furthermore, they were located at two positions (near the bed and near the water surface). The results showed that for a circular pier, the slots with the lengths of b and 2b, located near the water surface, had no influence on the equilibrium scour depth. It was also found that for all piers, maximum reduction in scour depth occurred for piers with a slot length yl=2b and close to the bed. Also, the efficacy of a slot for scour protection in the case of a round-nosed pier was more than a circular pier (with a diameter equal to the width of a round-nosed pier). M3 ER -