Analysis of RC beams strengthened with FRP sheets under shear and flexure using MCFT

Document Type : Article

Authors

1 Department of Civil Engineering, Isfahan University of Technology (IUT), Isfahan, Iran

2 Department of Civil Engineering, Sama Technical and Vocatinal Training College, Islamic Azad University, Saveh Branch, Saveh, Iran

Abstract

Shear behavior of reinforced concrete (RC) beams strengthened with fiber reinforced polymers (FRP) sheets is studied in this paper using modified compression field theory(MCFT). The beam is considered to be under the combined effects of shear force and bending moment. Equilibrium and compatibility equations, as well as stress-strain relationships are developed for an element in the strengthened beam. Due to the extensive computations, a computer program wasdeveloped to solve the governing equations. The accuracy of the presented method herewas verified by the experimental results of 84 strengthened RC beams reported in the literature. Comparison between the measured and predicted results shows that the method can predict the shear behavior of the beam throughout its entire range leading up to failure. The method can also incorporate the effect of debonding of the FRP sheets in the analysis. The results of a case study indicates that preventing thedebonding of theFRP sheets from the web of the beam adds significantly to  the shear capacity, and in certain cases changes the failure mode from brittle to ductile.

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Main Subjects


References:
1. Denton, S.R., Shave, J.D., and Porter, A.D. "Shear strengthening of reinforced concrete structures using FRP composites", Proc. of the Second Int. Conf. on Advanced Polymer Composites for Structural Applications in Construction, Guildford, University of Surry, UK, pp. 134-143 (2004).
2. Chen, J.F. and Teng, J.G. "Shear capacity of fiberreinforced polymer-strengthened reinforced concrete beams: fiber reinforced polymer rupture", J. of Struct. Eng., 129(5), pp. 615-625 (2003).
3. Chen, J.F. and Teng, J.G. "Shear capacity of FRPstrengthened RC beams: FRP debonding", Const. Build. Mat., 17(1), pp. 27-41 (2003).
4. Colotti, V., Spadea, G., and Swamy, R.N. "Analytical model to evaluate failure of plated reinforced concrete beams strengthened for shear", ACI Struct. J., 101(6), pp. 755-764 (2004).
5. Colotti, V. and Swamy, R.N. "Unified Analytical approach for determining shear capacity of RC beams strengthened with FRP", Eng. Struct., 33(3), pp. 827- 842 (2011).
6. Kim, G.Y., Sim, J.O., and Oh, H.O. "Shear strengthened RC beams with FRPs in shear", Const. Build. Mat., 22(6), pp. 1261-1270 (2008).
7. Lu, X.Z., Chen, J.F., Ye, L.P., Teng, J.G., and Rotter, J.M. "RC beams shear-strengthened with FRP: Stress distribution in the FRP reinforcement", Const. Build. Mat., 23(4), pp. 1544-1554 (2009).
8. Perera, R., Barchin, M., Arteaga, A., and Diego, A. "Prediction of the ultimate strength of reinforced concrete beams FRP-strengthened in shear using neural networks", Composites: Part B, 41(4), pp. 287-298 (2010).
9. Tanarslan, H.M. "Predicting the capacity of RC beams strengthened in shear with side-bonded FRP reinforcements using artificial neural networks", Compos. Interf., 18(7), pp. 587-614 (2011).
10. Triantafillou, T.C. "Shear strengthening of reinforced concrete beams using epoxy-bonded FRP composites", ACI Struct. J., 95(2), pp. 107-115 (1998).
11. Triantafillou, T.C. and Antonopuolos, C.P. "Design of concrete  flexural members strengthened in shear with FRP", J. Compos. Constr., 4(4), pp. 198-205 (2000).
12. Teo, W. and Hor, Y. "Suitability of optimized truss model to predict the FRP contribution to shear resistance for externally bonded FRP strengthened RC beams without internal stirrups", Composites Part B: Engineering, 80, pp. 385-398 (2015).
13. Sayed, A.M., Wang, X., and Wu, Z. "Finite element modeling of the shear capacity of RC beams strengthened with FRP sheets by considering different failure modes", Const. Build. Mat., 59, pp. 169-179 (2014).
14. Colotti, V. "Shear interaction effect between transverse reinforcements in FRP-strengthened RC beams", Composites Part B: Engineering, 45(1), pp. 1222-1233 (2013).
15. Domenico, D. "RC members strengthened with externally bonded FRP plates: A FE-based limit analysis approach", Composites Part B: Engineering, 71, pp. 159-174 (2015).
16. Oller, E., Mar, A., Bairan, J.M., and Cladera, A. "Shear design of reinforced concrete beams with FRP longitudinal and transverse reinforcement", Composites Part B: Engineering, 74(1), pp. 104-122 (2015).
17. Colotti, V. "Mechanical shear strength model for reinforced concrete beams strengthened with FRP materials", Construction and Building Materials, 124, pp. 855-865 (2016).
18. Lee, D.H., Han, S.J., Kim, K.S., and Lafave, J.M. "Shear strength of reinforced concrete beams strengthened in shear using externally-bonded FRP composites", Composite Structures, 173, pp. 177-187 (2017).
19. Malek, A.M. and Saadatmanesh, H. "Ultimate shear capacity of reinforced concrete beams strengthened with web-bonded fiber-reinforced plastic plates", ACI Struct. J., 95(4), pp. 391-399 (1998).
20. Gendron, G., Picard, A., and Guerin, M.C. "A theoretical study on shear strengthening of reinforced concrete beams using composite plates", Compos. Struct, 45(4), pp. 303-309 (1999).
21. Stratford, T. and Burgoyne, C. "Shear analysis of concrete with brittle reinforcement", J. Compos. Constr., 7(4), pp. 323-330 (2003).
22. Vecchio, F.J. and Collins, M.P. "The modified compression-field theory for reinforced concrete elements subjected to shear", ACI Struct. J., 83(2), pp. 219-231 (1986).
23. ACI Committee 440, Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthened Concrete Structures, ACI 440.2R-08 (2008).
24. Vecchio, F.J. and Collins, M.P. "Predicting the response of reinforced concrete beams subjected to shear using modified compression field theory", ACI Struct. J., 85, pp. 258-268 (1998).
25. Chen, J.F. and Teng, J.G. "Anchorage strength models for FRP and sheet plates bonded to concrete", J. of Struct. Eng., 127(7), pp. 784-791 (2001).
26. Khalifa, A., Gold, W.J., Nanni, A., and Abdel Aziz, M.I. "Contribution of externally bonded FRP to shear capacity of RC flexural members", J. Compos. Constr., 2(4), pp. 195-202 (1998).
27. Adhikary, B.B., Mutsuyoshi, H., and Ashraf, M. "Shear strengthening of reinforced concrete beams using fiber-reinforced polymer sheets with bonded anchorage", ACI Struct. J., 101(5), pp. 660-668 (2004).
28. Adhikary, B.B. and Mutsuyoshi, H. "Behavior of concrete beams strengthened in shear with carbon- fiber sheets", J. Compos. Constr., 8(3), pp. 258-264 (2004).
29. Khalifa, A. and Nanni, A. "Rehabilitation of rectangular simply supported RC beams with shear deficiencies using CFRP composites", Const. Build. Mat., 16(3), pp. 135-146 (2002).
30. Khalifa, A. and Nanni, A. "Improving shear capacity of existing RC T-section beams using CFRP composites", Cem. Conc. Compos., 22(3), pp. 165-174 (2000).
31. Chaallal, O., Shahawy, M., and Hassan, M. "Performance of reinforced concrete T-girders strengthened in shear with carbon fiber-reinforced polymer fabric", ACI Struct. J., 99(3), pp. 335-343 (2002).
32. Li, A., Diagana, C., and Delmas, Y. "Shear strengthened effect by bonded composite fabrics on RC beams", Composites: Part B, 33(3), pp. 225-239 (2002).
33. Diagana, C., Li, A., Gedalia, B., and Delmas, Y. "Shear strengthening effectiveness with CFF strips", Eng. Struct., 25(4), pp. 507-516 (2003).
34. Al-Sulaimani, G.J., Sharif, A., Basunbul, I.A., Baluch, M.H., and Ghaleb, B.N. "Shear repair for reinforced concrete by fiberglass plate bonding", ACI Struct. J., 91(3), pp. 458-464 (1994).
35. Chajes, M.J., Januszka, T.F., Mertz, D.R., Thomson, T.A., and Finch, W.W. "Shear strengthening of reinforced concrete beams using externally applied composites fabrics", ACI Struct. J., 92(3), pp. 295-303 (1995).
36. Norris, T., Saadatmanesh, H., and Ehsani, M.R. "Shear and  flexural strengthening of R/C beams with carbon fiber sheets", J. of Struct. Eng., 123(7), pp. 903-911 (1997).
37. Li, A., Diagana, C., and Delmas, Y. "CFRP contribution to shear capacity of strengthened RC beams", Eng. Struct., 23(10), pp. 1212-1220 (2001).
38. Taljsten, B. "Strengthening concrete beams for shear with CFRP sheets", Const. Build. Mat., 17(1), pp. 15- 26 (2003).
39. Wong, R.S.Y. and Vecchio, F.J. "Towards modeling of reinforced concrete members with externally bonded fiber-reinforced polymer composites", ACI Struct. J., 100(1), pp. 47-55 (2003).
40. Deniaud, C. and Cheng, J.J.R. "Reinforced concrete T-beams strengthened in shear with fiber reinforced polymer sheets", J. Compos. Constr., 7(4), pp. 302- 310 (2003).
41. Lanniruberto, U. and Limbimbo, M. "Role of reinforced plastic sheets in shear response of reinforced concrete beams: experimental and analytical results", J. Compos. Constr., 8(5), pp. 415-424 (2004).
42. Bousselham, A. and Chaallal, O. "Effect of transverse steel and shear span on the performance of RC beams strengthened in shear with CFRP", Composites: Part B, 37(1), pp. 37-46 (2006).