» Research Note « Impact of Channel Contraction on the Abutment Scour and Application of Submerged Vanes in Scour Prevention and Control

Document Type : Technical Note

Authors

1 Head of Water Engineering Department, Shahrekord University

2 Ph.D. student

Abstract

When a bridge pier or abutment is built on a river bed, a contraction in the river flow section occurs. Under this condition, in addition to local scour at pier and abutments, contraction scour also takes place on the river bed. The objective of the present study is to investigate the effect of channel contraction on abutment scour and application of submerged vanes to prevent or control it. For this purpose, four different contraction sections, of 0.833, 0.667, 0.500 and 0.333 relative width are installed in an experimental flume furnished with non-cohesive materials with median size of 0.78 mm. In this research, three double vanes were tested. Vanes were arranged with three angles of attack namely, 10, 20 and 30 degrees with respect to the channel center line. All experiments were repeated for 3 discharges, 20, 30 and 40 lit/sec. Results of this research showed that the maximum reduction in the bed elevation due to scouring was 75 percent for relative width of, 0.833 of angle of attack of 20̊ and relative flow equal to 0.5. 

Keywords


رضاپوریان س. قربانی ب. و صمدی بروجنی ح. (1388). "مقایسه آزمایشگاهی تأثیر قرارگیری سری صفحه­های مستغرق در بالادست و پایین­دست پایه استوانه­ای در کنترل آب­شستگی موضعی، هشتمین سمینار بین اللمللی مهندسی رودخانه"، دانشگاه شهید چمران اهواز، ص.ص. 221-230.
شفاعی بجستان، م.، (1373). هیدرولیک رسوب. انتشارات دانشگاه شهید چمران، اهواز.
Chang F. and Davis S. (1998). "Maryland SHA procedure for estimating scour at bridge abutments". ASCE. Copendium of Conference Scour Paper. pp. 412-416.
Dey s. and Barbhuiya A. K. (2004). "Clear-water scour at abutments in thinly erored beds". Journal of Hydraulic Engineering. ASCE.130. pp. 622-634.
Ghorbani B. and Kells J. A. (2008). "Effect of submerged vanes on the scour occurring at a cylindrical pier". Journal of Hydraulic Engineering. 46 (4). pp.123-134.
Johnson P. A. Hey R. D. Tessier M. and Rosgen D. L. (2001). "Use of vanes for control of scour at vertical wall abutment". Journal of Hydraulic Engineering. ASCE. 127(9). pp. 772-779.
Komura, S. (1966). "Equilibrium depth of scour in long constrictions". Journal of the Hydraulics Division, American Society of Civil Engineers, Vol. 92, No. HY5, pp. 17-37.
Laursen, E.M. (1963). "Scour at bridge crossings". Trans. ASCE, Vol. 127, part 1, p. 166.
Laursen, E.M. (1963). "An analysis of relief bridge scour". Journal of Hydraulic Division, ASCE, Vol. ASCE, Vol. 89, No. HY3, pp. 106-109.
Lauchlan C. S. (1999). "Pier scour countermeasures". PhD Thesis, University of Auckland, New Zealand, pp. 299- 316.
Liu H.K. Chang F.M. and Skinner M.M. (1961). "Effect of bridge construction on scour and backwater". CER 60 HKL 22. Colorado State University. Civil Engineering Section. Fort Collins, Colorado.
Molinas A. and Kheireldin K. (1998). "Shear stress around vertical wall abutments". Journal of Hydraulic Engineering. ASCE. 124: 822-830.
Raudkivi A.J. and Ettma R. (1983). "Clear-water scour at cylindrical piers". Journal of
Hydraulic Engineering. ASCE. 109 (3). pp. 338-350.
USBR, (1977), Design of small dams, United States Government Printing Office, p. 816.
  • Receive Date: 07 October 2015
  • Revise Date: 11 March 2016
  • Accept Date: 11 April 2016
  • First Publish Date: 11 April 2016