Abstract
An experimental study was carried out on nine reinforced concrete beams with insufficient shear strength to evaluate the shear behavior and performance of beams. One of the beams was not strengthened and designated as the reference beam. Six of them were strengthened in both flexure and shear using two types of composite materials—carbon and glass fiber-reinforced polymer (CFRP and GFRP). Two of them were strengthened with U-wrapped and side-bonded CFRP in only shear. The experimental parameters involve the type of FRP, the number of FRP layers, the clear distance between two adjacent FRP shear strips and the strengthening configuration (completely wrapped, U wrapped and side bonded). The experimental results revealed that (i) applying the FRP sheets for strengthening improved the load carrying and deflection capacities of the tested beams by an average of 143% and 170%, respectively, (ii) strengthening with two layers of CFRP shear strips could transform the failure mode from shear to more ductile flexural failure, (iii) the load-carrying capacity of GFRP-strengthened beams was on the average 34% less than the capacities of those strengthened with CFRP and (iv) using additional CFRP layers for shear strengthening did not provide a proportional increase in strength. The experimental FRP contribution to the shear strength was estimated using equations proposed by various codes and researchers, and the prediction accuracy of the equations was evaluated statistically.
Similar content being viewed by others
Availability of data and material
No data was used for the research described in the article.
Code availability
Not applicable.
References
Adhikary BB, Mutsuyoshi H, Ashraf M (2004) Shear strengthening of reinforced concrete beams using fiber-reinforced polymer sheets with bonded anchorage. Struct J 101(5):660–668
Adhikary BB, Mutsuyoshi H, Ashraf M (2003) Effective shear strengthening of concrete beams using FRP sheets with bonded anchorage. In; Fibre-reinforced polymer reinforcement for concrete structures, pp 457–466. https://doi.org/10.1142/9789812704863_0042
Akkaya HC, Aydemir C, Arslan G (2022a) An experimental research on reinforced concrete deep beams fully wrapped with fiber reinforced polymers against shear. Case Stud Constr Mater 17:e01198. https://doi.org/10.1016/j.cscm.2022.e01198
Akkaya HC, Aydemir C, Arslan G (2022b) Investigation on shear behavior of reinforced concrete deep beams without shear reinforcement strengthened with fiber reinforced polymers. Case Stud Constr Mater 17:e01392. https://doi.org/10.1016/j.cscm.2022.e01392
Allam SM, Ebeido TI (2003) Retrofitting of RC beams predamaged in shear using CFRP sheets. Alex Eng J 42(1):16
Al-Rousan R (2020) Predicting the optimum shear capacity of reinforced concrete beams externally strengthened with CFRP composites. Proced Manuf 44:631–638
American Concrete Institute & Committee Fiber Reinforced Plastic Reinforcement (2017) Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. American Concrete Institute, Farmington hills
Anvari A, Babanajad S, Gandomi AH (2023) Data-driven prediction models for total shear strength of reinforced concrete beams with fiber reinforced polymers using an evolutionary machine learning approach. Eng Struct 276:115292. https://doi.org/10.1016/j.engstruct.2022.115292
Baggio D, Soudki K, Noël M (2014) Strengthening of shear critical RC beams with various FRP systems. Constr Build Mater 66:634–644. https://doi.org/10.1016/j.conbuildmat.2014.05.097
Benzeguir ZEA, El-Saikaly G, Chaallal O (2019) Size effect in RC T-beams strengthened in shear with externally bonded CFRP sheets: experimental study. J Compos Constr 23(6):04019048. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000975
Bousselham A, Chaallal O (2006) Effect of transverse steel and shear span on the performance of RC beams strengthened in shear with CFRP. Compos B Eng 37(1):37–46. https://doi.org/10.1016/j.compositesb.2005.05.012
Bukhari IA, Vollum RL, Ahmad S, Sagaseta J (2010) Shear strengthening of reinforced concrete beams with CFRP. Mag Concr Res 62(1):65–77. https://doi.org/10.1680/macr.2008.62.1.65
Cakir F, Aydin MR, Acar V, Aksar B, Akkaya HC (2023) An experimental study on RC beams shear-strengthened with intraply hybrid U-jackets composites monitored by digital image correlation (DIC). Compos Struct 323:117503. https://doi.org/10.1016/j.compstruct.2023.117503
CAN/CSA (2002) Design and construction of building components with fiber-reinforced polymer. S806-02, Canadian Standards Association, Rexdale, Canada
Cao SY, Chen JF, Teng JG, Hao Z, Chen J (2005) Debonding in RC beams shear strengthened with complete FRP wraps. J Compos Constr 9(5):417–428. https://doi.org/10.1061/(ASCE)1090-0268(2005)9:5(417)
Carolin A, Täljsten B (2005) Experimental study of strengthening for increased shear bearing capacity. J Compos Constr 9(6):488–496. https://doi.org/10.1061/(ASCE)1090-0268(2005)9:6(488)
CECS 146 (2003) Technical specification for strengthening concrete structure with carbon fiber reinforced polymer laminate. Association for Engineering Construction Standardization, Chin Planning Press, Beijing
Chen JF, Teng JG (2003a) Shear capacity of fiber-reinforced polymer-strengthened reinforced concrete beams: fiber reinforced polymer rupture. J Struct Eng 129(5):615–625. https://doi.org/10.1061/(ASCE)0733-9445(2003)129:5(615)
Chen JF, Teng JG (2003b) Shear capacity of FRP-strengthened RC beams: FRP debonding. Constr Build Mater 17(1):27–41. https://doi.org/10.1016/S0950-0618(02)00091-0
CNR-Italian Research Council, Advisory Committee on Technical Recommendations for Construction (2004) Guide for the design and construction of externally bonded FRP systems for strengthening existing structures. Materials, RC and PC Structures, Masonry Structures (CNR-DT 200/ 2004). Rome, Italy
DAfStb (2012) German Committee for Structural Concrete: Strengthening of concrete members with adhesively bonded reinforcement. German
CIDAR (2006) Design Guideline for RC structures retrofitted with FRP and metal plates: beams and slabs. Draft 3 - Submitted To Standards Australia, The University of Adelaide, p 206
Diagana C, Li A, Gedalia B, Delmas Y (2003) Shear strengthening effectiveness with CFF strips. Eng Struct 25(4):507–516. https://doi.org/10.1016/S0141-0296(02)00208-0
Dong J, Wang Q, Guan Z (2013) Structural behaviour of RC beams with external flexural and flexural–shear strengthening by FRP sheets. Compos B Eng 44(1):604–612. https://doi.org/10.1016/j.compositesb.2012.02.018
Godat A, Qu Z, Lu XZ, Labossière P, Ye LP, Neale KW (2010) Size effects for reinforced concrete beams strengthened in shear with CFRP strips. J Compos Constr 14(3):260–271. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000072
Grace NF, Sayed GA, Soliman AK, Saleh KR (1999) Strengthening reinforced concrete beams using fiber reinforced polymer (FRP) laminates. ACI Struct J 96(5):865–875
Grande E, Imbimbo M, Rasulo A (2009) Effect of transverse steel on the response of RC beams strengthened in shear by FRP: experimental study. J Compos Constr 13(5):405–414. https://doi.org/10.1061/(ASCE)1090-0268(2009)13:5(405)
Haddad RH, Almomani OA (2019) Flexural performance and failure modes of NSM CFRP-strengthened concrete beams: a parametric study. Int J Civil Eng 17(7):935–948. https://doi.org/10.1007/s40999-018-0342-8
Haddad RH, Marji CS (2019) Composite strips with U-shaped CFRP wrap anchor systems for strengthening reinforced concrete beams. Int J Civil Eng 17(11):1799–1811. https://doi.org/10.1007/s40999-019-00447-w
Ianniruberto U, Imbimbo M (2004) Role of fiber reinforced plastic sheets in shear response of reinforced concrete beams: experimental and analytical results. J Compos Constr 8(5):415–424. https://doi.org/10.1061/(ASCE)1090-0268(2004)8:5(415)
Ibrahim B, Leblouba M, Altoubat S, Barakat S (2021) Shear strength of externally U-bonded carbon fiber-reinforced polymer high-strength reinforced concrete. Materials 14(13):3659. https://doi.org/10.3390/ma14133659
International Federation for Structural Concrete (Ed) (2001) Externally bonded FRP reinforcement for RC structures: technical report on the design and use of externally bonded fibre reinforced polymer reinforcement (FRP EBR) for reinforced concrete structures. fib
ISIS Design Manual 4 (2001) Strengthening reinforced concrete structures with externally-bonded fiber reinforced polymers, ıntelligent sensing for ınnovative structures, Winnipeg, Canada
Jayaprakash J, Abdul Samad AA, Ashrabov AA, Choong KK (2011) Experimental investigation on shear resistance behaviour of RC precracked and non-precracked T-beams using discrete CFRP strips. Int J Integr Eng 1(2):1–15
Jin L, Jiang X, Lu K, Du X (2022) Tests on shear failure and size effect of CFRP-wrapped RC beams without stirrups: influence of CFRP ratio. Compos Struct 291:115613. https://doi.org/10.1016/j.compstruct.2022.115613
JSCE Japanese Society of Civil Engineers (2000) Recommendations for upgrading of concrete structures with use of continuous fiber sheets
Kar S, Biswal KC (2020) Shear strengthening of reinforced concrete T-beams by using fiber-reinforced polymer composites: a data analysis. Arab J Sci Eng 45(5):4203–4234. https://doi.org/10.1007/s13369-020-04412-x
Keskin RSO, Arslan G, Sengun K (2017a) Influence of CFRP on the shear strength of RC and SFRC beams. Constr Build Mater 153:16–24. https://doi.org/10.1016/j.conbuildmat.2017.06.170
Keskin RSO, Sengun K, Arslan G (2017) Retrofıttıng SFRC beams by usıng CFRP. Eng Sci 6
Khalifa A (1999) Shear performance of reinforced concrete beams strengthened with advanced composites. University of Alexandria, Egypt, DISS
Khalifa A, Nanni A (2000) Improving shear capacity of existing RC T-section beams using CFRP composites. Cement Concr Compos 22(3):165–174. https://doi.org/10.1016/S0958-9465(99)00051-7
Khalifa A, Nanni A (2002) Rehabilitation of rectangular simply supported RC beams with shear deficiencies using CFRP composites. Constr Build Mater 16(3):135–146. https://doi.org/10.1016/S0950-0618(02)00002-8
Khalifa A, Gold WJ, Nanni A, Mı AA (1998) Contribution of externally bonded FRP to shear capacity of RC flexural members. J Compos Constr 2(4):195–202
Kim G, Sim J, Oh H (2008) Shear strength of strengthened RC beams with FRPs in shear. Constr Build Mater 22(6):1261–1270. https://doi.org/10.1016/j.conbuildmat.2007.01.021
Kotynia R (2021) Shear strengthening of RC beams with polymer composites. Associate Professor Thesis, Łod´z
Kotynia R, Oller E, Marí A, Kaszubska M (2021) Efficiency of shear strengthening of RC beams with externally bonded FRP materials – State-of-the-art in the experimental tests. Compos Struct 267:113891
Leung CKY, Chen Z, Lee S, Ng M, Xu M, Tang J (2007) Effect of size on the failure of geometrically similar concrete beams strengthened in shear with FRP strips. J Compos Constr 11(5):487–496. https://doi.org/10.1061/(ASCE)1090-0268(2007)11:5(487)
Li W, Leung CKY (2016) Shear span-depth ratio effect on behavior of RC beam shear strengthened with full-wrapping FRP strip. J Compos Constr 20(3):04015067. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000627
Li W, Leung CKY (2017) Effect of shear span-depth ratio on mechanical performance of RC beams strengthened in shear with U-wrapping FRP strips. Compos Struct 177:141–157. https://doi.org/10.1016/j.compstruct.2017.06.059
Lima JL, Barros JA (2011) Reliability analysis of shear strengthening externally bonded FRP models. Proc Inst Civil Eng Struct Build 164(1):43–56. https://doi.org/10.1680/stbu.9.00042
Marani A, Nehdi ML (2022) Predicting shear strength of FRP-reinforced concrete beams using novel synthetic data driven deep learning. Eng Struct 257:114083. https://doi.org/10.1016/j.engstruct.2022.114083
Mercimek Ö (2023) Experimental and analytical investigation of the effects of anchor types and strip shapes on shear-deficient reinforced concrete beams strengthened with TRM versus FRP. Int J Civil Eng. https://doi.org/10.1007/s40999-023-00866-w
Mofidi A, Chaallal O (2011a) Shear strengthening of RC beams with EB FRP: influencing factors and conceptual debonding model. J Compos Constr 15(1):62–74. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000153
Mofidi A, Chaallal O (2011b) Shear strengthening of RC beams with externally bonded FRP composites: effect of strip-width-to-strip-spacing ratio. J Compos Constr 15(5):732–742. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000219
Mofidi A, Chaallal O (2014) Tests and design provisions for reinforced-concrete beams strengthened in shear using FRP sheets and strips. Int J Concr Struct Mater 8(2):117–128. https://doi.org/10.1007/s40069-013-0060-1
Mostofinejad D, Shameli SM (2013) Externally bonded reinforcement in grooves (EBRIG) technique to postpone debonding of FRP sheets in strengthened concrete beams. Constr Build Mater 38:751–758. https://doi.org/10.1016/j.conbuildmat.2012.09.030
Mostofinejad D, Tabatabaei Kashani A (2013) Experimental study on effect of EBR and EBROG methods on debonding of FRP sheets used for shear strengthening of RC beams. Compos B Eng 45(1):1704–1713. https://doi.org/10.1016/j.compositesb.2012.09.081
Mostofinejad D, Hosseini SA, Razavi SB (2016a) Influence of different bonding and wrapping techniques on performance of beams strengthened in shear using CFRP reinforcement. Constr Build Mater 116:310–320. https://doi.org/10.1016/j.conbuildmat.2016.04.113
Mostofinejad D, Tabatabaei Kashani A, Hosseini A (2016b) Design model for shear capacity of RC beams strengthened with two-side CFRP wraps based on effective FRP strain concept. Eur J Environ Civ Eng 20(2):161–179. https://doi.org/10.1080/19648189.2015.1021382
Mostofinejad D, Esfahani MR, Shomali A (2019) Experimental and numerical study of the RC beams shear-strengthened with NSM technique. J Compos Mater 53(17):2377–2389. https://doi.org/10.1177/0021998319830777
Oller E, Kotynia R, Marí A (2021) Assessment of the existing models to evaluate the shear strength contribution of externally bonded frp shear reinforcements. Compos Struct 266:113641. https://doi.org/10.1016/j.compstruct.2021.113641
Ozden S, Atalay HM, Akpinar E, Erdogan H, Vulaş YZ (2014) Shear strengthening of reinforced concrete T-beams with fully or partially bonded fibre-reinforced polymer composites. Struct Concr 15(2):229–239. https://doi.org/10.1002/suco.201300031
Ozturk M, Sengun K, Arslan G (2023) CFRP contribution to load-carrying capacity of retrofitted geopolymer concrete beams. Structures 48:1391–1402. https://doi.org/10.1016/j.istruc.2023.01.028
Panda KC, Bhattacharyya SK, Barai SV (2011) Shear strengthening of RC T-beams with externally side bonded GFRP sheet. J Reinf Plast Compos 30(13):1139–1154. https://doi.org/10.1177/0731684411417202
Panda KC, Bhattacharyya SK, Barai SV (2013) Effect of transverse steel on the performance of RC T-beams strengthened in shear zone with GFRP sheet. Constr Build Mater 41:79–90. https://doi.org/10.1016/j.conbuildmat.2012.11.098
Pellegrino C, Modena C (2002) Fiber reinforced polymer shear strengthening of reinforced concrete beams with transverse steel reinforcement. J Compos Constr 6(2):104–111. https://doi.org/10.1061/(ASCE)1090-0268(2002)6:2(104)
Pellegrino C, Modena C (2006) Fiber-reinforced polymer shear strengthening of reinforced concrete beams: experimental study and analytical modeling. ACI Struct J 103(5):720–728
Pellegrino C, Modena C (2008) An experimentally based analytical model for the shear capacity of FRP-strengthened reinforced concrete beams. Mech Compos Mater 44(3):231–244. https://doi.org/10.1007/s11029-008-9016-y
Pellegrino C, Vasic M (2013) Assessment of design procedures for the use of externally bonded FRP composites in shear strengthening of reinforced concrete beams. Compos B Eng 45(1):727–741. https://doi.org/10.1016/j.compositesb.2012.07.039
Rashidi M, Takhtfirouzeh H (2018) An experimental study on shear and flexural strengthening of concrete beams using GFRP composites. Int J Integr Eng 3(1):1–7
Şengün K, Arslan G (2017) Influence of CFRP on the strength of retrofitted RC beams without stirrups. Sigma J Eng Natural Sci 35(1):77–85
Sengun K, Arslan G (2022a) Investigation of the parameters affecting the behavior of RC beams strengthened with FRP. Front Struct Civ Eng 16(6):729–743. https://doi.org/10.1007/s11709-022-0854-9
Sengun K, Arslan G (2022b) Parameters affecting the behaviour of RC beams strengthened in shear and flexure with various FRP systems. Structures 40:202–212. https://doi.org/10.1016/j.istruc.2022.04.024
Sharkawi AEDM, Etman E (2007) Effect of shear strengthening on the flexural behavior of RC simple beams strengthened externally with FRP laminates. In Twelfth ınternational colloquium on structural and geotechnical engineering, Ain Shams University, Faculty of Engineering, Department of Structural Engineering, pp 10–12
Shomali A, Mostofinejad D, Esfahani MR (2020) Effective strain of CFRP in RC beams strengthened in shear with NSM reinforcements. Structures 23:635–645. https://doi.org/10.1016/j.istruc.2019.10.020
Shomali A, Mostofinejad D, Esfahani MR (2021) Shear strengthening of RC beams using EBRIG CFRP strips: a comparative study. Eur J Environ Civ Eng 25(14):2540–2556. https://doi.org/10.1080/19648189.2019.1633413
Sundarraja MC, Rajamohan S (2009) Strengthening of RC beams in shear using GFRP inclined strips – An experimental study. Constr Build Mater 23(2):856–864. https://doi.org/10.1016/j.conbuildmat.2008.04.008
Teng JG, Chen GM, Chen JF, Rosenboom OA, Lam L (2009) Behavior of RC beams shear strengthened with bonded or unbonded FRP wraps. J Compos Constr 13(5):394–404. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000040
Tran CTN, Nguyen XH, Nguyen HC, Le DD (2021) Shear performance of short-span FRP-reinforced concrete beams strengthened with CFRP and TRC. Eng Struct 242:112548. https://doi.org/10.1016/j.engstruct.2021.112548
Triantafillou TC (1998) Shear strengthening of reinforced concrete beams using epoxy-bonded FRP composites. ACI Struct J 95(2):107–115
Triantafillou TC, Antonopoulos CP (2000) Design of concrete flexural members strengthened in shear with FRP. J Compos Constr 4(4):198–205. https://doi.org/10.1061/(ASCE)1090-0268(2000)4:4(198)
Van Cao V, Pham SQ (2019) Comparison of CFRP and GFRP wraps on reducing seismic damage of deficient reinforced concrete structures. Int J Civil Eng 17(11):1667–1681. https://doi.org/10.1007/s40999-019-00429-y
Funding
The authors did not receive support from any organization for the submitted work.
Author information
Authors and Affiliations
Contributions
[KS] was involved in conceptualization, [GA] helped in methodology, [KS] contributed to formal analysis and investigation, [KS] helped in writing—original draft preparation; [GA] helped in writing—review and editing, [GA] was involved in supervision, [GA] contributed to data curation.
Corresponding author
Ethics declarations
Conflict of interest
The authors have no conflict of interest to declare that are relevant to the content of this article.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Sengun, K., Arslan, G. Performance of RC Beams Strengthened in Flexure and Shear with CFRP and GFRP. Iran J Sci Technol Trans Civ Eng 48, 117–130 (2024). https://doi.org/10.1007/s40996-023-01305-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s40996-023-01305-5