Effects of hooked-collar on the local scour around a lenticular bridge pier

作     者：Rashid Farooq Amir Hossein Azimi Muhammad Atiq Ur Rehman Tariq Afzal Ahmed Rashid Farooq;Amir Hossein Azimi;Muhammad Atiq Ur Rehman Tariq;Afzal Ahmed

作者机构：Department of Civil Engineering International Islamic University Department of Civil Engineering Lakehead University College of Engineering and Science Victoria University Department of Civil Engineering University of Engineering and Technology James Watt School of Engineering University of Glasgow 

出 版 物：《International Journal of Sediment Research》 (国际泥沙研究(英文版))

年 卷 期：2023年第38卷第1期

页      面：1-11页

核心收录：

学科分类：0830[工学-环境科学与工程（可授工学、理学、农学学位）] 08[工学] 0815[工学-水利工程] 0814[工学-土木工程] 

基　　金：partially supported by the NSERC Discovery grant No. 421785 

主　　题：Local scour Erosion Collar Hooked-collar Lenticular pier Scour countermeasure Steady flow 

摘      要：This paper presents the results of comprehensive laboratory experiments to investigate the effects of hooked-collar on the scour development around a vertical pier with a lenticular cross section. The flow around the pier was uniform, steady, and under the clear-water condition. The axial scour profiles for cases without and with a lenticular hooked-collar were measured and the effects of hooked-collar dimensions and elevation from the bed were examined. To compute the efficiency of hooked-collar for scour prevention, the results of local scour for a bridge pier without a collar and a bridge pier with a plain collar, without a hooked wall, were used as benchmark data sets. A wide range of hooked-collar geometries such as the ratio of collar width to the pier width, Wc/Wp, ranging from 1.5 to 3.5, the ratio of hooked-collar wall height to the pier width, Hc/Wp, ranging from 0.15 to 0.6, and the ratio of collar elevation to the pier width, Ec/Wp, of-0.5, 0, and 0.5 were tested. The experimental results indicated that the equilibrium scour depth decreased with the ratio of hooked-collar to the pier width when Wcis twice the pier width, Wp. For Wc/Wp 2, the scour depth was similar to the tests with an infinitely large pier width. In addition, the scour depth consistently reduced as the hooked-collar wall height, Hc, to the pier width, Wp, approached 0.3. The highest scour reduction efficiency was achieved when the hooked-collar being placed on the bed surface. Empirical models were developed for prediction of maximum scour depth near the lenticular bridge pier with a modified collar. The results showed that the volume of scour hole around a lenticular pier increased non-linearly with the maximum scour depth and it was independent of the hooked-collar geometry.