Experimental Study on the Effect of Circular Collar on Cylindrical Bridge Pier Scour in Unsteady Flow

Document Type : Research Article

Authors

1 Department of Water Engineering and Management, Tarbiat Modares University, Tehran, Iran

2 Department of Water Science and Engineering, Shahid Bahonar University, Kerman, Iran

Abstract

The bridge pier scour is one of the major causes of bridge destruction worldwide. Despite extensive research in this field, the study of this topic has always been of interest to researchers and it is necessary to study different methods to counter it. The collar is a simple and inexpensive structure for protection against bridge pier scour. In this study, the effect of collar size and height on bridge pier scour and determination of the best collar performance conditions in steady and unsteady flow conditions were investigated. The experiments used three different collar sizes and three different mounting heights relative to the substrate surface. After calculating the percentage of scour reduction in all test cases and comparing them, investigation of time evolution diagram of scour hole and comparison of maximum depth of scouring created in different states, It was found that increasing the size of the collar and decreasing the height of the collar installation relative to the substrate surface resulted in a further decrease in the depth of the bridge pier scour and this change was more evident in the unsteady flow state. Also by comparing the two variables of size and height of collar installation, it was found that the height of collar with dimensionless ratio H/D=0.5 in steady and unsteady flow had the best performance and the greatest effect in reduction scour around bridge pier.

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Main Subjects

References

[1] M. Shafaei bajestan, Hydraulic of sediment transport, 4nd Ed, Shahid Chamran University of Ahvaz Publications, 2016. (in Persian)
[2] M. Javanmard, M. Heydarpour, The effect of cable in controlling and reduction around the bridge pier local scour, International Conference on Agriculture, Environment and Natural Resources in the Third Millennium, 22 May 2017, Rasht, Iran. (in Persian)
[3] Y.-M. Chiew, Scour protection at bridge piers, Journal of Hydraulic Engineering, 118(9) (1992) 1260-1269.
[4] M. Heidarpour, H. Afzalimehr, E. Izadinia, Reduction of local scour around bridge pier groups using collars, International Journal of Sediment Research, 25(4) (2010) 411-422.
[5] A.R. Zarrati, M.R. Chamani, A. Shafaie, M. Latifi, Scour countermeasures for cylindrical piers using riprap and combination of collar and riprap, International Journal of Sediment Research, 25(3) (2010) 313-322.
[6] N. Hasanpour, A. Hosseinzadeh Dalir, H. Arounaghi, Investigation of local scour around airfoil shaped pier with collar, Journal of water and soil science, 23(3) (2013) 221-234. (in Persian)
[7] A.R. Zarrati, H. Gholami, M. Mashahir, Application of collar to control scouring around rectangular bridge piers, Journal of Hydraulic Research, 42(1) (2004) 97-103.
[8] C. Singh, B. Setia, D. Verma, Collar-sleeve combination as a scour protection device around a circular pier, in:  Proceedings of the congress-international association for hydraulic research, 2001, pp. 202-209.
[9] A.M. Negm, G.M. Moustafa, Y.M. Abdalla, A.A. Fathy, Optimal shape of collar to minimize local scour around bridge piers, Proc. of IWTC13,  (2009) 12-15.
[10] S.Y. Kumcu, M.A. Kokpinar, M. Gogus, Scour protection around vertical-wall bridge abutments with collars, KSCE Journal of Civil Engineering, 18(6) (2014) 1884-1895.
[11 ]M. Karimi, K. Qaderi, M. Rahimpour, M.M. Ahmadi, Determine the most suitable collar submergence ratio at abutment scour, The 2nd International and 3nd National Conference on Agriculture, Environment and Food Security, 6 March 2019, Jiroft, Iran. (in Persian)
[12] J.-S. Lai, W.-Y. Chang, C.-L. Yen, Maximum local scour depth at bridge piers under unsteady flow, Journal of Hydraulic Engineering, 135(7) (2009) 609-614.
[13] M.K. Tabarestani, A.R. Zarrati, Local scour calculation around bridge pier during flood event, KSCE Journal of Civil Engineering, 21(4) (2017) 1462-1472.
[14] A.J. Raudkivi, Loose boundary hydraulics, CRC Press, Balkema, Rotterdam, Netherlands, 1998.
[15] R. Ettema, Scour at bridge piers, Report No. 216, Department of Civil Engineering, University of Auckland, 1980.
[16] V. Kumar, K.G.R. Raju, N. Vittal, Reduction of local scour around bridge piers using slots and collars, Journal of Hydraulic Engineering, 125(12) (1999) 1302-1305.
[17] A.J. Raudkivi, R. Ettema, Clear-water scour at cylindrical piers, Journal of Hydraulic Engineering, 109(3) (1983) 338-350.
[18] Y. Chiew, B. Melville, Local scour around bridge piers, Journal of Hydraulic Research, 25(1) (1987) 15-26.
[19] S. Franzetti, S. Malavasi, C. Piccinin, Sull'erosione alla base delle pile di ponte in acque chiare, in:  XXIV Convegno di Idraulica e Costruzioni Idrauliche, 1994, pp. 1-13.
[20] Bagherian, H. Experimental study on the effect of circular pier tilt on scouring depth in non-steady flow conditions, MS Thesis, Tarbiat modares university, Tehran, Iran, 2018. (Persian)
[21] Shariati, H. Investigation of collar and slot performance in scour reduction of bridge pier, MS Thesis, Ferdowsi University of Mashhad, Mashhad, Iran, 2009. (in Persian)
[22] Ghasemi Gavarti, Z. Effect of sacrificial pile with slot and collar on reduction of local scour around bridge pier, MS Thesis, Shiraz University, Shiraz, Iran, 2015. (in Persian)
[23] Amini, M.M, Investigation on simultaneous effect of collar and slot in Reduction local scour of cylindrical pier groups, MS Thesis, Isfahan University of Technology, Isfahan, Iran, 2016. (in Persian).
[24] A. Zarrati, S.M. Azizi, Control of scouring in the around bridge pier, Journal of Technical College University of Tehran, 35(1) (2001) 21-33. (in Persian)
[25] M. Gholamzadeh Mahmoudi, M. Shafaei Bajestan, Influence of collar placement on local scour around the cylinder bridge piers in meandring river, 8th International River Engineering Conference, 26 and 28 January 2010, Ahvaz, Iran. (In Persian).
[26] A. Masjedi, M.S. Bejestan, A. Esfandi, Experimental study on local scour around single oblong pier fitted with a collar in a 180 degree flume bend, International Journal of Sediment Research, 25(3) (2010) 304-312.
[27] H. Sanikhani, A. Hosseinzadeh Dalir, D. Farsadizadeh, A. Fakherifard, A. Nazemi, F. Salmasi, Application of rectangular and circular collars in reducing of bridge piers scour, Journal of Agricultural Science, 18(4) (2008) 1-16. (in Persian)
[28]M. Aghli, S.M. Zomorodian, Effect of cable and collar on scouring depth around cylindrical bridge pier in meandering river, Journal of Irrigation Science and Engineering, 36(3) (2013) 31-40. (in Persian)
Amirkabir Journal of Civil Engineering
Volume 53, Issue 5
August 2021
Pages 1721-1742

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