Structural Engineering and Mechanics

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

Flexural strengthening of continuous unbonded post-tensioned concrete beams with end-anchored CFRP laminates

  • Ghasemi, Saeed (Civil Engineering Department, Shahid Bahonar University) ;
  • Maghsoudi, Ali A. (Civil Engineering Department, Shahid Bahonar University) ;
  • Bengar, Habib A. (Civil Engineering Department, University of Mazandaran) ;
  • Ronagh, Hamid R. (Civil Engineering Department, University of Queensland)
  • Received : 2013.11.11
  • Accepted : 2014.10.02
  • Published : 2015.03.25
⟨ Previous Next ⟩

Abstract

This paper provides the results of an experimental investigation into the flexural behavior of continuous two-span unbonded post-tensioned high strength concrete (HSC) beams, strengthened by end-anchored CFRP laminates of different configurations in the hogging region. Implementing two different configurations of end-anchorage systems consisting of steel plates and bolts and carefully monitoring the development of strains throughout the load history using sufficiently large number of strain gauges, the response of beams including the observed crack propagations, beam deflection, modes of failure, capacity enhancement at service and ultimate and the amount of moment redistribution are measured, presented and discussed. The study is appropriate in the sense that it covers the more commonly occurring two span beams instead of the simply supported beams investigated by others. The experiments reconfirmed the finding of others that proper installation of composite strengthening system is most important in the quality of the bond which is essential for the internal transfer of forces. It was also found that for the tested two span continuous beams, the capacity enhancement is more pronounced at the serviceability level than the ultimate. This is an important finding as the design of these beams is mostly governed by the serviceability limit state signifying the appropriateness of the suggested strengthening method. The paper provides quantitative data on the amount of this capacity enhancement.

Keywords

References

  1. ACI Committee 318 R (2011), Building Code Requirements for Structural Concrete and Commentary, American Concrete Institute, Farmington Hills, MI.
  2. ACI Committee 440.2R (2008), Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures, American Concrete Institute, Detroit, MI, 76p.
  3. Akbarzadeh Bengar, H. and Maghsoudi, A.A. (2010), "Experimental investigations and verification of debonding strain of RHSC continuous beams strengthened in flexure with externally bonded FRPs", Mater. Struct., 43, 815-837. https://doi.org/10.1617/s11527-009-9550-7
  4. Akbarzadeh, H. and Maghsoudi, A.A. (2010), "Experimental and analytical investigation of reinforced high strength concrete continuous Beams strengthened with fibre reinforced polymer", Mater. Des., 31, 1130- 1147. https://doi.org/10.1016/j.matdes.2009.09.041
  5. ASTM 370A (2012), Standard Test Methods and Definitions for Mechanical Testing of Steel Products, American society for testing and materials (ASTM), West Conshohocken, USA.
  6. Bank, L.C. and Arora, D. (2006), "Analysis of RC beams strengthened with mechanically fastened FRP (MF-FRP) strips", Compos. Struct., 79, 180-191.
  7. Brena, S.F., Bramblett, R.M., Wood, S. and Kreger, M. (2003), "Increasing flexural capacity of reinforced concrete beams using carbon fiber-reinforced polymer composites", ACI Struct. J., 100(1), 36-46.
  8. BS 8110 (1997), Structural Use of Concrete, Part 1, British Standards Institution, Milton Keynes, UK.
  9. BS EN 12390-3 (2009), Testing hardened concrete. Compressive strength of test specimens, British standards institution, Milton Keynes, UK.
  10. Chahrour, A. and Soudki, K. (2005), "Flexural response of reinforced concrete beams strengthened with end-anchored partially bonded carbon fiber-reinforced polymer strips", J. Compos. Constr., ASCE, 9(2), 170-177. https://doi.org/10.1061/(ASCE)1090-0268(2005)9:2(170)
  11. Chakrabari, P.R. (2005), "Behavior of un-bonded post-tensioned beams repaired and retrofitted with composite materials", ASCE Structures Congress, Metropolis and Beyond, NY, April.
  12. El-Meski, F. and Harajli, M. (2012), "Flexural behavior of unbonded post-tensioned concrete members strengthened using external frp composites", J. Compos. Constr., ASCE, 17(2), 197-207.
  13. El-Refaie, S.A., Ashour, A.F. and Garrity, S.W. (2003), "Sagging and hogging strengthening of continuous reinforced concrete beams using carbon fiber-reinforced polymer sheets", ACI Struct. J., 100(4), 446-453.
  14. Farahbod, F. and Mostofinejad, D. (2010), "Experimental study of moment redistribution in RC frames strengthened with CFRP sheets", Compos. Struct., 93, 1168-1177.
  15. Foret, G. and Limam, O. (2008), "Experimental and numerical analysis of RC two-way slabs strengthened with NSM CFRP rods", Constr. Build. Mater., 22, 2025-2030. https://doi.org/10.1016/j.conbuildmat.2007.07.027
  16. Garden, H.N. and Hollaway, L.C. (1998), "An experimental study of the influence of plate endanchorage of carbon fibre composite plates used to strengthen reinforced concrete beams", Compos. Struct., 42, 175-188. https://doi.org/10.1016/S0263-8223(98)00070-1
  17. Ghasemi S. (2012), "Behavior of continuous un-bounded post-tensioned concrete members strengthened with cfrp laminates (Experimental Investigation)", MSc Dissertation, Shahid Bahonar University of Kerman, Kerman, Iran.
  18. Iranian concrete code (Mabhas 9) (2009), Design and Construction of Reinforced Concrete Buildings, National Building Codes, Tehran, Iran.
  19. Klaiber F.W. and Wipf T.J. (2003), "Repair of damaged prestressed concrete bridges using CFRP", Proceeding of M.C.T.R. Symposium, Ames, Iowa State University.
  20. Lamanna, A.J., Bank, L.C. and Scott, D.W. (2001), "Flexural strengthening of reinforced concrete beams using fasteners and fiber-reinforced polymer strips", ACI Struct. J., 98(3), 368-376.
  21. Lignola, G.P., Prota, A., Manfredi, G. and Cosenza, E. (2007), "Experimental performance of RC hollow columns confined with CFRP", J. Compos. Constr., ASCE, 11(1), 42-49. https://doi.org/10.1061/(ASCE)1090-0268(2007)11:1(42)
  22. Meier, U., Deuring, M., Meier, H. and Schwegler, G. (1993), Strengthening of Structures with Advanced Composites, Alternative Materials for Reinforcement and Prestressing of Concrete, Clarke/Chapman & Hall, Glasgow, Scotland.
  23. Mirmiran, A., Shahawy, M., Nanni, A. and Karbhari, V. (2004), "Bonded repair and retrofit of concrete structures using FRP composites", National Cooperative Highway Research Program (NCHRP) Report 514, Transportation Research Board.
  24. Pellegrino, C. and Modena, C. (2009), "Flexural strengthening of real-scale rc beams with end-anchored pretensioned frp laminates", ACI Struct. J., 106(3), 319-328.
  25. Rosenboom, O., Hassan, T.K. and Rizkalla, S. (2007), "Flexural behavior of aged prestressed concrete girders strengthened with various FRP systems", Constr. Build. Mater., 21, 764-776. https://doi.org/10.1016/j.conbuildmat.2006.06.007
  26. Rosenboom, O., Walter, C. and Rizkalla, S. (2009), "Strengthening of prestressed concrete girders with composites: Installation, design and inspection", Constr. Build. Mater., 23, 1495-1507. https://doi.org/10.1016/j.conbuildmat.2007.11.010
  27. Schiebel, S., Parretti, R. and Nanni, A. (2001), "Repair and strengthening of impacted PC girders on bridge A4845", Missouri Department of Transportation Report RDT01-017/RI01-016.
  28. Takacs, P.F. and Kanstad, T. (2002), "Strengthening prestressed concrete beams with carbon fiber reinforced polymer plates", NTNU Report R-9-00, Norway.
  29. Teng, J.G., Chen, J.F., Smith, S.T. and Lam, L. (2002), FRP Strengthened RC Structures, Wiley, New York.
  30. Warwaruk, J., Sozen, M.A. and Siess, C.P. (1962), "Investigation of prestressed concrete for highway bridges, part III: strength and behavior in flexure of prestressed beams", Bulletin No. 464, Engineering Experiment Station, University of Illinois, Urbana.

Cited by

  1. Improvement of Mechanical Properties of Railway Track Concrete Sleepers Using Steel Fibers vol.28, pp.11, 2016, https://doi.org/10.1061/(ASCE)MT.1943-5533.0001646
  2. Experimental and Theoretical Serviceability of Strengthened and Nonstrengthened Unbonded Posttensioned Indeterminate I-Beams vol.22, pp.7, 2017, https://doi.org/10.1061/(ASCE)BE.1943-5592.0001047
  3. Behavior of Strengthened Composite Prestressed Concrete Girders under Static and Repeated Loading vol.2017, 2017, https://doi.org/10.1155/2017/3619545
  4. An Experimental Study on Concrete Flat Slabs Prestressed with Carbon Fibre Reinforced Polymer Sheets vol.2015, 2015, https://doi.org/10.1155/2015/792320
  5. Effect of soil overburden pressure on mechanical properties of carbon FRP strips vol.61, pp.5, 2015, https://doi.org/10.12989/sem.2017.61.5.637
  6. Analytical and numerical studies on hollow core slabs strengthened with hybrid FRP and overlay techniques vol.65, pp.5, 2018, https://doi.org/10.12989/sem.2018.65.5.535
  7. Debonding failure analysis of prestressed FRP strengthened RC beams vol.66, pp.4, 2015, https://doi.org/10.12989/sem.2018.66.4.543
  8. Flexural tests on two-span unbonded post-tensioned lightweight concrete beams vol.72, pp.5, 2019, https://doi.org/10.12989/sem.2019.72.5.631
  9. A new anchorage system for CFRP strips in externally strengthened RC continuous beams vol.30, pp.None, 2015, https://doi.org/10.1016/j.jobe.2020.101230
  10. PVC and POM gripping mechanisms for tension testing of FRP bars vol.77, pp.1, 2021, https://doi.org/10.12989/sem.2021.77.1.075