Analytical Assessment of Bending Ductility in FRP Strengthened RHSC Beams
Over the past few years, a wide use of externally-bonded fiber-reinforced polymer composites (EB-FRP), for rehabilitation, strengthening and repair of existing/deteriorated reinforced/prestressed-concrete (RC/PC) structures has been observed. This paper presents a nonlinear iterative analytical approach conducted to investigate the effects of concrete strength, steel-reinforcement ratio and externally-reinforcement (FRP) stiffness on the flexural behavior and the curvature ductility index of the FRP-strengthened reinforced high-strength concrete (RHSC) beams. Analysis results using the proposed technique have shown very good agreement with the experimental data of FRP-strengthened/non-strengthened RHSC beams, regarding moment–curvature response, ultimate moment and failure mode. Also, a newly prediction equation for the curvature ductility index of FRP strengthened RHSC beams has been developed and verified. Then, converting equation of the curvature ductility index to energy one is proposed. Results indicate that the proposed predictions for the curvature and energy ductility indices are accurate to within 1.87% and 3.03% error for practical applications, respectively. Finally, limit values for these bending ductility indices, based on different design codes’ criterion, are assessed and discussed.
Rasheed, H.R. “Strengthening design of reinforced concrete with FRP” (2015). doi:10.1201/b17968.
Teng, J.G., S.T. Smith, J. Yao, and J.F. Chen. “Intermediate crack-induced debonding in RC beams and slabs.” Construction and Building Materials 17 (September 2003): 447-462. doi:10.1016/s0950-0618(03)00043-6.
Ashour, A.F., S.A. El-Refaie, and S.W. Garrity. “Flexural strengthening of RC continuous beams using CFRP laminates.” Cement and Concrete Composite 26 (October 2004): 765-775. doi:10.1016/j.cemconcomp.2003.07.002.
Akbarzadeh, H., and A.A. Maghsoudi. “Experimental and analytical investigation of reinforced high strength concrete continuous beams strengthened with fiber reinforced polymer.” Materials and Design 31 (March 2010): 1130-1147. doi:10.1016/j.matdes.2009.09.041.
Akbarzadeh, H., and A.A. Maghsoudi. “Experimental investigations and verification of debonding strain of RHSC continuous beams strengthened in flexure with externally bonded FRPs.” Materials and Structures 43 (2010): 815-837. doi:10.1617/s11527-009-9550-7.
Cruz-Noguez, C.A., D.T. Lau, E.G. Sherwood, S. Hiotakis, J. Lombard, S. Foo and M. Cheung. “Seismic behavior of RC shear walls strengthened for in-plane bending using externally bonded FRP sheets.” Journal of Composites for Construction (ASCE) 19 (1) (February 2015): 04014023. doi:10.1061/(asce)cc.1943-5614.0000478.
Mostofinejad, D., and N. Moshiri. “Compressive strength of CFRP composites used for strengthening of RC columns: comparative evaluation of EBR and grooving methods.” Journal of Composites for Construction (ASCE) 19 (5) (October 2015): 04014079. doi:10.1061/(asce)cc.1943-5614.0000545.
Ghasemi, S., A.A. Maghsoudi, H. Akbarzadeh Bengar, and H.R. Ronagh. “Sagging and hogging strengthening of continuous unbonded posttensioned HSC beams by NSM and EBR.” Journal of Composites for Construction (ASCE) 20 (2) (April 2016): 04015056. doi:10.1061/(asce)cc.1943-5614.0000621.
Qeshta, I.M.I., P. Shafigh, and M.Z. Jumaat. “Research progress on the flexural behaviour of externally bonded RC beams.” Archives of Civil and Mechanical Engineering 16 (4) (September 2016): 982–1003. doi:10.1016/j.acme.2016.07.002.
Mostofinejad, D., and A.R. Akhlaghi. “Experimental investigation of the efficacy of EBROG method in seismic rehabilitation of deficient reinforced concrete beam–column joints using CFRP sheets.” Journal of Composites for Construction (ASCE) 21 (4) (August 2017): 04016116. doi:10.1061/(asce)cc.1943-5614.0000781.
Oehlers, D.J. “Development of design rules for retrofitting by adhesive bonding or bolting either FRP or steel plates to RC beams or slabs in bridges and building.” Composites: Part A 32 (September 2001): 1345-1355. doi:10.1016/s1359-835x(01)00089-6.
ACI 363R. “State-of-the-art report on high-strength concrete.” American Concrete Institute (2010).
Rashid, M.A., M.A. Mansur, and P. Paramasivam. “Correlations between mechanical properties of high-strength concrete.” Journal of Materials in Civil Engineering (ASCE) 14 (3) (June 2002): 230-238. doi:10.1061/(asce)0899-1561(2002)14:3(230).
Maghsoudi, A.A. “Design for Ductility of Structures.” Shahid Bahonar University Publications (1996) [in Persian].
Maghsoudi, M., and A.A. Maghsoudi. “Moment redistribution and ductility of CFRP strengthened and non-strengthened unbonded post-tensioned indeterminate I-beams composed of UHSSCC.” Composite Structures 174 (August 2017): 196–210. doi:10.1016/j.compstruct.2017.04.057.
Lee, H.J. “Predictions of curvature ductility factor of doubly reinforced concrete beams with high strength materials.” Computers and Concrete (An International Journal) 12 (6) (December 2013): 831-850. doi:10.12989/cac.2013.12.6.831.
Lee, T., A.D.E Pan, and M.J.L. Ma. “Ductile design of reinforced concrete beams retrofitted with fiber reinforced polymer plates.” Journal of Composites for Construction (ASCE) 8 (6) (December 2004): 489-500. doi:10.1061/(asce)1090-0268(2004)8:6(489).
Matthys, S., and L. Taerwe. “Evaluation of ductility requirements in current design guidelines for FRP strengthening.” Cement and Concrete Composites 28 (10) (November 2006): 845–856. doi:10.1016/j.cemconcomp.2006.07.003.
Yost, J.R., and R.E. Steffen. “Strength and ductility trends for concrete members strengthened in flexure with carbon fiber-reinforced polymer reinforcement.” Journal of Composites for Construction (ASCE) 18 (6) (December 2014): 04014015. doi:10.1061/(asce)cc.1943-5614.0000460.
Teng, J.G., J.F. Chen, S.T. Smith, and L. Lam. “FRP strengthened RC structures” (2002).
An, W., H. Saadatmanesh, and M.R. Ehsani. “RC beams strengthened with FRP plates - Part II: analysis and parametric study.” Journal of Structural Engineering (ASCE) 117 (11) (November 1991): 3434–3455. doi:10.1061/(asce)0733-9445(1991)117:11(3434).
El-Mihilmy, M.T. , and J.W. Tedesco. “Analysis of reinforced concrete beams strengthened with FRP laminates.” Journal of Structural Engineering (ASCE) 126 (6) (June 2000): 684–691. doi:10.1061/(asce)0733-9445(2000)126:6(684).
Toutanji, H., L. Zhao, and Y. Zhang. “Flexural behavior of reinforced concrete beams externally strengthened with CFRP sheets bonded with an inorganic matrix.” Engineering Structures 28 (March 2006): 557–566. doi:10.1016/j.engstruct.2005.09.011.
Skuturna, T., and J. Valivonis. “The statistical evaluation of design methods of the load-carrying capacity of flexural reinforced concrete elements strengthened with FRP.” Archives of Civil and Mechanical Engineering 15 (1) (January 2015): 214–222. doi:10.1016/j.acme.2014.04.005.
ACI 440.2R. “Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures.” American Concrete Institute (2017).
Thorenfeldt, E., A. Tomaszewicz, and J.J. Jensen. “Mechanical properties of high strength concrete and application in design.” Proceedings of the Symposium on Utilization of High Strength Concrete (1987).
Popovics, S. “A numerical approach to the complete stress-strain curve of concrete.” Cement and Concrete Research 3 (5) (September 1973): 583–599. doi:10.1016/0008-8846(73)90096-3.
Collins, M.P., and A. Porasz. “Shear design for high-strength concrete.” Comité Euro-International du Béton, Bulletin d’Information 193 (1989): 77-83.
CSA A23.3. “Design of concrete structures.” Canadian Standards Association (2004).
ACI 318. “Building code requirements for structural concrete and commentary.” American Concrete Institute (2014).
Eurocode 2. “Design of concrete structures-Part 1: General rules and rules for Buildings.” European Committee for Standardization (2004).
NZS 3101. “Concrete structures standard–Part 1: The design of concrete structures.” Standards New Zealand (2006).
Hashemi, S.H., A.A. Maghsoudi, and R. Rahgozar. “Bending response of HSRC beams strengthened with FRP sheets.” Scientia Iranica: Transaction A 16 (2) (2009): 138-146.
Maghsoudi, A.A., and H. Akbarzadeh. “Flexural ductility of HSC members.” Structural Engineering and Mechanics (An International Journal) 24 (2) (September 2006): 195-212. doi:10.12989/sem.2006.24.2.195.
Rashid, M.A., and M.A. Mansur. “Reinforced high-strength concrete beams in flexure.” ACI Structural Journal 102 (3) (2005): 462-471. doi:10.14359/14418.
Rabinovitch, O., and Y. Frostig. “Experiments and analytical comparison of RC beams strengthened with CFRP composites.” Composites: Part B 34 (December 2003): 663-677. doi:10.1016/s1359-8368(03)00090-8.
Rahimi, H., and A. Hutchinson. “Concrete beams strengthened with externally bonded FRP plates.” Journal of Composites for Construction (ASCE) 5 (1) (February 2001): 44-56. doi:10.1061/(asce)1090-0268(2001)5:1(44).
- There are currently no refbacks.
Copyright (c) 2018 Houman Ebrahimpour Komleh, Ali Akbar Maghsoudi
This work is licensed under a Creative Commons Attribution 4.0 International License.