Effects of increasing the width of collar on reduction of scouring surrounding the rectangular piers in a 180-degree bend

Abstract Employment of protective structures is vital for reducing the effect local scour created surrounding bridge piers. One most effective used controlling and piers collars. Hence, research on mechanism scouring combination pier collar as well reduction great significance. In this study, various width-to-pier width ratios parameters rectangular has been investigated experimentally in 180-degree sharp bend positions. The experiments were conducted under clear water threshold sediment motion upstream straight path. Results indicated that collars with equal to 3 4 perform best at maximum depth front nose Increasing reduces scouring. length efficiency effectiveness delaying process amount reduction. highest occurred vicinity 90-degree section installed a ratio 2 by approximately 75 70%, respectively.