Shear Retrofitting of Corner 3D-Reinforced Concrete Beam-Column Joints Using Externally Bonded CFRP Reinforcement on Grooves
Publication: Journal of Composites for Construction
Volume 22, Issue 5
Abstract
Beam-column joints are fundamental structural components to provide stability to a concrete frame. Compared to other types of joint, corner joints are more susceptible to failure due to their smaller size and inferior confinement; therefore, it is necessary to develop efficient techniques for strengthening three-dimensional (3D) corner deficient joints of reinforced concrete (RC) structures. However, most research has focused on two-dimensional (2D) joints due to the complexity of casting and testing 3D ones. Moreover, the effect of lateral beams on the confinement of the joint zone has been neglected in most cases. These shortcomings undermine the applicability of some of the retrofitting configurations proposed so far to real 3D structures. This study investigates the shear strengthening of nonseismic 3D corner joints, i.e., those lacking adequate transverse reinforcement in the joint zone, using carbon fiber reinforced polymer (CFRP) sheets. To delay the debonding of CFRP sheets off the concrete substrate, the externally bonded reinforcement on groove (EBROG) technique is used, and the hysteretic response of 3D corner joints strengthened via the EBROG method is analyzed. Five 3D joint specimens in half-scale size were manufactured and tested. The specimens consisted of one control specimen, one standard specimen conforming to code requirements, and three FRP-retrofitted specimens with L-shaped strengthening configurations. Results indicated that the adopted strengthening configurations prevented the shear failure of the joint. Furthermore, the EBROG method enhanced the load-carrying capacity and ductility of the RC joints by up to 38 and 69% respectively, compared with the control specimen. Comparison of the maximum loads achieved at a drift ratio of 4.5% revealed that the EBROG technique combined with CFRP fans prevented any load reduction up to the test termination.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The authors would like to extend their gratitude to the research vice chancellor’s office of Isfahan University of Technology (IUT) for its financial support; also to Bonyad Beton Company-Isfahan for the materials they supplied. Furthermore, the technical support of Eng. Nematollah Jamali and his colleagues in Pishro Sanat Co. on the testing system and apparatus is greatly appreciated.
References
ACI (American Concrete Institute). 2005. Acceptance criteria for moment frames based on structural testing and commentary. ACI 374.1-05. Farmington Hills, MI: ACI.
ACI (American Concrete Institute). 2014. Building code requirements for structural concrete and commentary. ACI 318-14. Farmington Hills, MI: ACI.
Antonopoulos, C. P., and T. C. Triantafillou. 2003. “Experimental investigation of FRP-strengthened RC beam-column joints.” J. Compos. Constr. 7 (1): 39–49. https://doi.org/10.1061/(ASCE)1090-0268(2003)7:1(39).
Del Vecchio, C., M. Di Ludovico, A. Balsamo, A. Prota, G. Manfredi, and M. Dolce. 2014. “Experimental investigation of exterior RC beam-column joints retrofitted with FRP systems.” J. Compos. Constr. 18 (4): 04014002. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000459.
Del Vecchio, C., M. Di Ludovico, A. Prota, and G. Manfredi. 2015. “Analytical model and design approach for FRP strengthening of non-conforming RC corner beam-column joints.” Eng. Struct. 87: 8–20. https://doi.org/10.1016/j.engstruct.2015.01.013.
El-Amoury, T., and A. Ghobarah. 2002. “Seismic rehabilitation of beam-column joint using GFRP sheets.” Eng. Struct. 24 (11): 1397–1407. https://doi.org/10.1016/S0141-0296(02)00081-0.
Gergely, J., C. Pantelides, and L. D. Reaveley. 2000. “Shear strengthening of RCT-joints using CFRP composites.” J. Compos. Constr. 4 (2): 56–64. https://doi.org/10.1061/(ASCE)1090-0268(2000)4:2(56).
Ghobarah, A., and A. Said. 2001. “Seismic rehabilitation of beam-column joints using FRP laminates.” J. Earthquake Eng. 5 (1): 113–129. https://doi.org/10.1080/13632460109350388.
Ghobarah, A., and A. Said. 2002. “Shear strengthening of beam-column joints.” Eng. Struct. 24 (7): 881–888. https://doi.org/10.1016/S0141-0296(02)00026-3.
Hadi, M. N. S., and T. M. Tran. 2015. “Seismic rehabilitation of reinforced concrete beam-column joints by bonding with concrete covers and wrapping with FRP composites.” Mater. Struct. 49 (1–2): 467–485. https://doi.org/10.1617/s11527-014-0511-4.
Hosseini, A., and D. Mostofinejad. 2013. “Experimental investigation into bond behavior of CFRP sheets attached to concrete using EBR and EBROG techniques.” Compos. Part B: Eng. 51 (Aug): 130–139. https://doi.org/10.1016/j.compositesb.2013.03.003.
Le-Trung, K., K. Lee, J. Lee, D. H. Lee, and S. Woo. 2010. “Experimental study of RC beam-column joints strengthened using CFRP composites.” Compos. Part B: Eng. 41 (1): 76–85. https://doi.org/10.1016/j.compositesb.2009.06.005.
Mosallam, A. S. 2000. “Strength and ductility of reinforced concrete moment frame connections strengthened with quasi-isotropic laminates.” Compos. Part B: Eng. 31 (6–7): 481–497. https://doi.org/10.1016/S1359-8368(99)00068-2.
Mostofinejad, D., and A. Akhlaghi. 2016. “Experimental investigation of the efficacy of EBROG method in seismic rehabilitation of deficient reinforced concrete beam-column joints using CFRP sheets.” J. Compos. Constr. 21 (4): 04016116. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000781.
Mostofinejad, D., and A. Akhlaghi. 2018. “Efficiency of grooving method used for deficient RC beam-column joints seismically rehabilitated with CFRP sheets.” In Proc., 2017 fib Symp. Cham, Switzerland: Springer.
Mostofinejad, D., and M. Hajrasouliha. 2013. “Effect of concrete strength and groove dimension on performance of grooving method to postpone debonding of FRP sheets in strengthened concrete beams.” Iran. J. Sci. Technol. Trans. B: Eng. 37 (2): 219–232.
Mostofinejad, D., and A. T. Kashani. 2013. “Experimental study on effect of EBR and EBROG methods on debonding of FRP sheets used for shear strengthening of RC beams.” Compos. Part B: Eng. 45 (1): 1704–1713. https://doi.org/10.1016/j.compositesb.2012.09.081.
Mostofinejad, D., and E. Mahmoudabadi. 2010. “Grooving as alternative method of surface preparation to postpone debonding of FRP laminates in concrete beams.” J. Compos. Constr. 14 (6): 804–811. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000117.
Mostofinejad, D., and N. Moshiri. 2014. “Compressive strength of CFRP composites used for strengthening of RC columns: Comparative evaluation of EBR and grooving methods.” J. Compos. Constr. 19 (5): 04014079. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000545.
Mostofinejad, D., and M. Shameli. 2013. “Externally bonded reinforcement in grooves (EBRIG) technique to postpone debonding of FRP sheets in strengthened concrete beams.” Constr. Build. Mater. 38 (Jan): 751–758. https://doi.org/10.1016/j.conbuildmat.2012.09.030.
Pantelides, C. P., Y. Okahashi, and L. Reaveley. 2008. “Seismic rehabilitation of reinforced concrete frame interior beam-column joints with FRP composites.” J. Compos. Constr. 12 (4): 435–445. https://doi.org/10.1061/(ASCE)1090-0268(2008)12:4(435).
Park, R. 1989. “Evaluation of ductility of structures and structural assemblages from laboratory testing.” Bull. N. Z. Soc. Earth. Eng. 22 (3): 155–166.
Parvin, A., S. Altay, C. Yalcin, and O. Kaya. 2010. “CFRP rehabilitation of concrete frame joints with inadequate shear and anchorage details.” J. Compos. Constr. 14 (1): 72–82. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000055.
Paulay, T., and M. Priestley. 1992. Seismic design of reinforced concrete and masonry buildings. New York: Wiley.
Priestley, M., and R. Park. 1987. “Strength and ductility of concrete bridge columns under seismic loading.” ACI Struct. J. 84 (1): 61–76.
Priestley, M., F. Seible, and G. M. Calvi. 1996. Seismic design and retrofit of bridges. New York: Wiley.
Said, A. M., and M. L. Nehdi. 2004. “Use of FRP for RC frames in seismic zones. I: evaluation of FRP beam-column joint rehabilitation techniques.” Appl. Compos. Mater. 11 (4): 205–226. https://doi.org/10.1023/B:ACMA.0000035462.41572.7a.
Shrestha, R., S. Smith, and B. Samali. 2009. “Strengthening RC beam-column connections with FRP strips.” Struct. Build. 162 (5): 323–334.
Sika Group. 2006. Product data sheet: Sika-Wrap300 C, woven carbon fiber fabric for structural strengthening. Zurich, Switzerland: Sika Group.
Information & Authors
Information
Published In
Copyright
©2018 American Society of Civil Engineers.
History
Received: Apr 18, 2017
Accepted: Mar 20, 2018
Published online: Jul 20, 2018
Published in print: Oct 1, 2018
Discussion open until: Dec 20, 2018
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.