The Effect of Sill to Reduce Scour Around Bridge Piers in Flood Flow Conditions

Document Type : Original Article

Authors

1 Graduate of water science and Engineering, College of Agriculture, Ferdowsi University of Mashhad

2 water science and engineering. ferdowsi university of mashhad- mashhad -Iran

3 Assistant professor Department. water science and Engineering, College of Agriculture, Ferdowsi University of Mashhad

Abstract

Scouring around bridge piers due to strong storm currents is a main threat to the stability of bridges in rivers. Hence, in this conditions the protection against excessive scouring is required. Attempts have been made by several investigators to reduce scour depth using several devices around bridge piers. One of the successful methods for reduction of scouring was the application of bed sills.  In this study, the effect of applying bed sill at the downstream of the pier in reducing the scour around bridge piers under strong storm currents is studied. For this purpose, experiments were conducted by placement of bed sills at the downstream of the pier throughout the flume width with its top position at the bed level and by varying the distance between bridge pier and bed sill. The experimental tests were done under uniform flow with clear water condition and storm currents. Storm currents were simulated by two group of hydrographs with different base time and three different peak flow. A circular pier was installed on the bed with uniform sediments and final scour depth was measured in different flow conditions. The results under uniform flow showed that the efficiency of the bed sill is reduced by increasing the distance between the bed sill and the base of pier. The placement of a bed sill sticking to the pier resulted in the most significant scour reduction of about 36 and 77 % in depth and volume, respectively. This result confirms the findings of previous studies. Under storm flow condition, the placement of bed sill at distances smaller than three times of the pier diameter resulted in the reduction of scour depth and volume. The results show that the efficiency of the bed sill is reduced significantly by increasing the distance from the pier and it results in the increase of scour depth at the distance of three pier diameter. The maximum reduction in scour depth and volume was observed about 25 and 48 %, respectively, at the condition with the bed sill sticking to the pier. Based on these findings, it can be concluded that the efficiency of the bed sill is reduced under storm flow conditions when compared with its efficiency under uniform flow with clear water condition.

Keywords

References

حیدرپور،م.، افضلی مهر،ح.، خدارحمی،ز. 1386. حفاظت گروه پایه­های استوانه­ای پل در برابر آبشستگی موضعی با استفاده از شکاف. مجله علوم کشاورزی و منابع طبیعی.
رازی،س.، دلیر،ع.،ح.، سلماسی،ف.، فرسادی زاده،د. 1391. تاثیر توام آستانه و طوق درکاهش عمق آبشستگی اطراف پایه­های پل استوانه­ای. نشریه آب و خاک . 26 .3: 597
Arneson,L.A., Zevenbergen,L.W., Lagasse,P.F and Clopper,P.E. 2012. Evaluating scour at bridges (HEC-18), Technical Rep. No. FHWA (Federal Highway Administration) HIF-12-003, Washington, DC.
Breusers,H.N.C and Raudkivi,A. J.  1991. Scouring. Hydraulic structure design manual, No 2 IAHR.  Balkema. 143p.
Chiew,Y.M. 1995. Mechanics of riprap failure at bridge piers, Journal of Hydraulic Engineering. 121.9:635–643.
Chiew,Y.M. 1992. Scour protection at bridges pier Journal of Hydraulic Engineering.  118.9: 1260–1269.
Chiew,Y.M and Lim,F.H. 2000. Failure behavior of riprap layer at bridge piers under live-bed conditions, Journal of Hydraulic Engineering. 126.1: 43–55.
Chabert,J and Engeldinger,P. 1956. Etude des affouillementsautour des piles de ponts, Laboratoire National d’hydraulique, Chatou, France.
Dey,S and Rajkumar,V.R. 2007. Clear-water scour at piers in sand beds with an armor layer of gravels. Journal of Hydr. Eng., ASCE, Vol. 133, No. 6, pp. 703–711.
Defanti,E., Di Pasquale,G., Poggi,D. 2010. An experimental studies of scour at bridge piers: Collars as a countermeasure, Proceeding 1st IAHR European Congress, Heriot-Watt University, Edinburgh, UK.
Ding,B., Chiew,Y.M., Tang,H.W. 2006. Scour Protection around Bridge Piers Using Tetrahedron Frames, Proceedings Third International Conference on Scour and Erosion, November 1-3
Ettema,R. 1980. Scour at bridge piers, Report. No. 112, Dept. of Civil Engineering, University of Auckland, Auckland, New Zealand.
Franzetti,S., Larcan,E and Mignosa.P. 1982. Influence of tests duration on the evaluation of ultimate scour around circular piers. Pp. 381-396. International Conference on the Hydraulic Modeling
of Civil Engineering Structures. September 22- 24, University of Warwick, Coventry, England.
Ghorbani,B., Kells,J.A. 2008. Effect of submerged vanes on the scour occurring at a cylindrical pier Journal of Hydraulic Research. 46.5: 610–619.
Grimaldi,C., Gaudio,R., Calomino,F., Cardoso,A.H. 2009. Control of scour at bridge piers by a downstream bed sill, Journal of Hydraulic Engineering. 135.1: 13–21
Heidarpour,M. 2002. Control and reduction of local scour at bridge piers by using slot, Proceeding. River Flow 2002.Louvain-la-Neuve, A. A. Balkema, Rotterdam, The Netherlands. 2: 1069–1072.
Hoffmans,G.J and Verheij,H.J. 1997. Scour manual. 5theden, London. Balkema Publishing. 205p.
Johnson,P.A., Hey,R.D., Brown,E.R., Rosgen,D.L. 2002. Stream restoration in the vicinity of bridges, Journal American Water Resource. Associate 381: 55–67.
Johnson,P.A 1995. Comparison of Pier-Scour Equations Using Field Data, Journal of Hydraulic. Engineering. 8: 626-629
Johnson, P.A., Hey,R.D., Tessier,M., Rosgen,D.L. 2001. Useof vanes for control of scour at vertical wall abutments,  Journal of Hydraulic Engineering. 127.9:772–778.
Kumar,V., RangaRaju,K.J., Vittal,N. 1999. Reduction of local scour around bridge piers using slots and collars. Journal of Hydraulic Engineering. 125.12: 1302–1305.
Lim,F.H and Chiew,Y.M. 2001. Parametric study of riprap protection around bridge piers Journal of Hydraulic Research. 39.1: 61–72.
Lauchlan,C.S. 1999. Pier scour countermeasures, Univ. of Auckland, School of Engineering, Rep. No. 590, Auckland, New Zealand.
Lauchlan,C.S and Melville,B.W.  2001. Riprap protection at bridge piers. Journal of Hydraulic Engineering. 127.5: 412–418.
Melville,B.W and Hadfield,A.C. 1999. Use of sacrificial piles as pier scour countermeasures. Journal of Hydraulic Engineering.  125.11: 1221–1224.
Mashahir,M.B., Zarrati,A.R., Mokallaf,E. 2010. Application of riprap and collar to prevent scouring around rectangular bridge piers. Journal of Hydraulic Engineering. 136.3: 183–187.
Melville,B.W., Coleman,S.E. 2000. Bridge scour,Water Resources Publications, Littleton, CO.
Odgaard,A.J., Wang,Y. 1987. cour prevention at bridge piers, Conference, Virginia.523–527.
Parker,G., Toro-Escobar,C., Voigt,R.L. 1998, Countermeasures to protect bridge piers from scour, Final Rep. prepared for National Highway Research Program, Transportation Research Board, National Research Council, University. of Minnesota, Minneapolis and December.
Pagliara,S., Carnacina,I., Cigni,F. 2010. Sills and gabions as countermeasures at bridge pier in presence of debris accumulations. Journal of Hydraulic. Research. 48.6: 764–774.
Razi,S., Salmasi,F., Dalir,A.H., Farsadizaeh,D. 2012. Application of Bed Sill to Control Scouring Around Cylindrical Bridge Piers, Journal of Civil Engineering and Urbanism. 2: 115-121
Rudkivi,A.J. Ettema.R. 1983. Clear-water scour at cylindrical piers. Journal of Hydraulic Engineering, ASCE, 109.3: 339-350.
Sheppard,D.M., Melville,B., Demir,H. 2014. Evaluation of existing equations for local scour at bridge piers Journal of Hydraulic. Engineering 10.1061: 14–23.
Tafarojnoruz,A., Gaudio,R., Calomino,F. 2012. Evaluation of Flow-Altering Countermeasures against Bridge Pier Scour, Journal of Hydraulic Engineering. 138.3: 297–305.
Vittal,N., Kothyari,U.C., Haghighat,M. 1994. Clear water scour around bridge pier group. Journal of Hydraulic Engineering.. 120.11: 1309–1319.
Yoon,T.H. 2005. Wire Gabion for Protecting Bridge Piers. Journal of Hydraulic Engineering. 131.11: 942–949.
Wang,T.W. 1994. A study of pier scouring and scour reduction. Proceeding. 9th Congress ., Asia Pacific Div., IAHR, Int. Assoc. for Hydraulic. Research, Delft, The Netherlands, Singapore. 18–28.
Zarrati,A.R., Gholami,H., Mashahir,M.B. 2004. Application of collar to control scouring around rectangular bridge piers, Journal of Hydraulic. Research. 42.1: 97–103.
Iranian Journal of Irrigation & Drainage
Volume 11, Issue 1 - Serial Number 61
May and June 2017
Pages 69-79

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