DOI QR코드

DOI QR Code

Flexural behavior of retrofitted RC columns by FRP-MF, Experimental approach

  • Mahdavi, Navideh (Department of Civil Engineering, Faculty of Engineering, Marand Branch, Islamic Azad University) ;
  • Tasnimi, Abbas Ali (Department of Structural Engineering, Faculty of Civil and Environmental Engineering, Tarbiat Modares University)
  • 투고 : 2018.10.28
  • 심사 : 2019.10.16
  • 발행 : 2019.11.10

초록

Most of the recent studies have improved the efficiency of FRP jackets for increasing the compressive strength, shear strength, and ductility of reinforced concrete columns; however, the influence of FRP jackets on the flexural capacity is slight. Although new methods such as NSM (near surface mounted) are utilized to solve this problem, yet practical difficulties, behavior dependency on adhesives, and brittle failure necessitate finding better methods. This paper presents the results of an experimental study on the application of fiber-reinforced polymer fastened mechanically to the concrete columns to improve the flexural capacity of RC columns. For this purpose, mechanical fasteners were used to achieve the composite behavior of FRP and concrete columns. The experimental program included five reinforced concrete columns retrofitted by different methods using FRP subjected to constant axial compression and lateral cyclic loading. The experimental results showed that the use of the new method proposed in this paper increased the flexural strength and lateral load capacity of the columns significantly, and good composite action of FRP and RC column was achieved. Moreover, the experimental results were compared with the results obtained from the analytical study based on strain compatibility, and good proximity was reached.

키워드

과제정보

연구 과제 주관 기관 : International Institute of Earthquake Engineering and Seismology (IIEES)

참고문헌

  1. ACI 211.1-91 (1991), Standard practice for selecting proportionfor normal, heavy weight and mass concrete, American Concrete Institute.
  2. ACI 318-14 (2014), Building code requirements for structural concrete, commentary on building code requirements for structural concretes, American Concrete Institute.
  3. ACI 440.2R-02 (2005), Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures, Reported by ACI Committee 440.
  4. Afefy, H.M.E.D., Mahmoud, M.H. and Fawzy, T.M. (2013), "Rehabilitation of defected RC stepped beams using CFRP", Eng. Struct., 49, 295-305. https://doi.org/10.1016/j.engstruct.2012.11.013
  5. Atea, R.S. (2017), "Torsional behavior of reinforced concrete T-beams strengthened with CFRP strips", Case Studies Constr. Mater., 7, 110-117. https://doi.org/10.1016/j.cscm.2017.03.002
  6. Bank, L.C. and Arora, D. (2007), "Analysis of RC beams strengthened with mechanically fastened FRP (MF-FRP) strips", J. Compos. Struct., 79(2), 180-191. https://doi.org/10.1016/j.compstruct.2005.12.001
  7. Behera, G.C., Rao, T.G. and Rao, C.B.K. (2016), "Torsional behavior of reinforced concrete beams with ferrocement Ujacketing-experimental study", Case Studies Constr. Mater., 4, 15-31. https://doi.org/10.1016/j.cscm.2015.10.003
  8. Bischof, P., Suter, R., Chatzi, E. and Lestuzzi, P. (2014), "On the use of CFRP sheets for the seismic retrofitting of masonry walls and the influence of mechanical anchorage", Polymers, 6(7), 1972-1998. https://doi.org/10.3390/polym6071972
  9. Ekenel, M., Rizzo, A., Myers, J.J. and Nanni, A. (2006), "Flexural fatigue behavior of reinforced concrete beams strengthened with FRP fabric and precured laminate systems", J. Compos. Constr., 10(5), 433-442. https://doi.org/10.1061/(ASCE)1090-0268(2006)10:5(433)
  10. Jawdhari, A. and Fam, A (2018), "Numerical study on mechanical and adhesive splices for ribbed GFRP plates used in concrete beams", Eng. Struct., 174, 478-494. https://doi.org/10.1016/j.engstruct.2018.07.085
  11. Jumaat, M.Z. and Alam, M.A. (2010), "Experimental and numerical analysis of end anchored steel plate and CFRP laminate flexural strengthened reinforced concrete (r. c.) beams", Int. J. Phys. Sci., 5, 132-144.
  12. Lezgy-Nazargah, M., Dezhangah, M. and Sepehrinia, M. (2018), "The effects of different FRP/concrete bond-slip laws on the 3D nonlinear FE modeling of retrofitted RC beams - A sensitivity analysis", Steel Compos. Struct., Int. J., 26(3), 347-360. https://doi.org/10.12989/scs.2018.26.3.347
  13. Lamanna, A.J. (2002), "Flexural strengthening of reinforced concrete beams with mechanically fastened fiber reinforced polymer strips", Ph.D. Thesis; University of Wisconsin-Madison, Madison, WI, USA.
  14. Mander, J.B., Priestley, M.J. and Park, R. (1988), "Theoretical stress-strain model for confined concrete", J. Struct. Eng., 114, 1804-1826. https://doi.org/10.1061/(ASCE)0733-9445(1988)114:8(1804)
  15. Martin, J.A. and Lamanna, A.J. (2008), "Performance of mechanically fastened FRP strengthened concrete beams in flexure", J. Compos. Constr., 12(3), 257-265. https://doi.org/10.1061/(ASCE)1090-0268(2008)12:3(257)
  16. Mayes, R.L. and Clough, R.W. (1975), "State of the art in seismic shear strength of masonry - An evaluation and review", EERC Report; Berkeley, CA, USA.
  17. Napoli, A., Matta, F., Martinelli, E., Nanni, A. and Realfonzo, R. (2010), "Modeling and verification of response of RC slabs strengthened in flexure with mechanically fastened FRP laminates", Magaz. Concrete Res., 62(8), 593-605. https://doi.org/10.1680/macr.2010.62.8.593
  18. Nardone, F., Lignola, G.P., Prota, A., Manfredi, G. and Nanni, A. (2011), "Modeling of flexural behavior of RC beams strengthened with mechanically fastened FRP strips", Compos. Struct., 93(8),1973-1985. https://doi.org/10.1016/j.compstruct.2011.03.003
  19. Promis, G. and Ferrier, E. (2012), "Performance indices to assess theefficiency of external FRP retrofittingof reinforced concrete shortcolumns for seismic strengthening", Constr. Build. Mater., 26(1), 32-40. https://doi.org/10.1016/j.conbuildmat.2011.04.067
  20. Rizzo, A., Galati, N., Nanni, A. and Bank, L.C. (2005), "Strengthening concrete structures with mechanically fastened pultruded strips", COMPOSITES 2005 Convention and Trade Show American Composites Manufacturers Association, Columbus, OH, USA, September.
  21. Saadatmanesh, H., Ehsani, M.R. and Li, M.W. (1994), "Strength and ductility of concrete columns externally reinforced with fiber composite straps", Struct. J., 91(4), 434-447.
  22. Standard No. 2800 (2015), Iranian code of practice for seismic resistant design of buildings, ministry of housing and urban development of Iran, (4rd Edition), Tehran, Iran.
  23. Tasnimi, A.A. (2000), "Strength and deformation of mid-rise shear walls under load reversal", J. Eng. Struct., 22(4), 311-322. https://doi.org/10.1016/S0141-0296(98)00110-2
  24. Wu, Z.S., Wang, X. and Iwashita, K. (2007), "State-of-the-art of advanced FRP applications in civil infrastructure in Japan", Compos. Polycon, 37, 1-17.