EVALUATION AND COMPARISON OF COLLAR AND COLLAR WITH SLOT METHODS IN REDUCING LOCAL SCOUR OF CYLINDRICAL BRIDGE PIERS

Many researchers have focused in recent years on the phenomenon of scour and providing different methods to control this phenomenon. The use of facilities, such as collar and slot on the pier to provide stability foe bridges can be appropriate ways to achieve this goal. In this study, with creating a slot on the pier and combining the collar and the slot, the impact of these two methods together to reduce the scour rate was investigated. The results showed that the square collar has a better performance than the circular collar in reducing the depth of scour due to having sharp edges. Combined methods are more effective than other methods, and the square collar with a slot method have a greater impact than other approaches so that in this method, the scour depth is reduced up to 80%.