Effect of Column Eccentricity on Beam-Column Joints Strengthened with Chamfers
Publication: Journal of Structural Engineering
Volume 148, Issue 8
Abstract
By installing unsymmetrical chamfers on the soffits of beams, it has been proved in the earlier studies to be effective for strengthening nonseismically designed beam-column joints (BCJs). To generalize this, this study aims to extend the strengthening strategy to BCJs having upper and lower columns of different sizes. Such column eccentricity is not uncommon in gravity-load designed structures. In this study, experimental studies were conducted on six scale specimens designed for joint shear failure, including three interior and three exterior specimens. The performance of specimens with nonseismic detailing was compared with that of having joint shear reinforcements or strengthened with chamfers. All specimens were under constant axial load and were subjected to cyclic displacements until failure. Response of chamfer under cyclic horizontal displacement was studied by analyzing the strains in chamfer. First and foremost, column eccentricity has both positive and negative influences on BCJs when subjected to cyclic displacements. Chamfer contributes to joint shear capacity when it is in compression. This leads to formation of an additional strut within the chamfer. For exterior joints, this phenomenon becomes obvious, and performance is improved when displacement is applied in one loading direction only. Lastly, width of additional strut formed in chamfer is associated with chamfer size.
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Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
The authors are grateful for the financial support from the General Research Fund of Innovation and Technology Support Programme (ITP/043/16NP), and technical support from the Structural Engineering Research Laboratory, Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University.
References
ACI-ASCE Committee 352 (American Concrete Institute-ASCE Committee 352). 2002. Recommendations for design of beam-column connections in monolithic reinforced concrete structures. ACI-ASCE Committee 352. Farmington Hills, MI: ACI.
Beschi, C., A. Meda, and P. Riva. 2011. “Column and joint retrofitting with high performance fiber reinforced concrete jacketing.” J. Earthquake Eng. 15 (7): 989–1014. https://doi.org/10.1080/13632469.2011.552167.
BSI (British Standards Institution). 2019. Testing fresh concrete Part 1: Sampling and common apparatus. BS EN 12350-1. London: BSI.
CEN (European Committee for Standardization). 2004. Design of structures for earthquake resistance-Part 1: General rules, seismic actions and rules for buildings. Eurocode 8. Brussels, Belgium: CEN.
Dang, C.-T., and N.-H. Dinh. 2017. “Experimental study on structural performance of RC exterior beam-column joints retrofitted by steel jacketing and haunch element under cyclic loading simulating earthquake excitation.” Adv. Civ. Eng. 2017. https://doi.org/10.1155/2017/9263460.
Engindeniz, M., L. F. Kahn, and Z. Abdul-Hamid. 2005. “Repair and strengthening of reinforced concrete beam-column join: State of the art.” Struct. J. 102 (2): 15.
Ghobarah, A., T. S. Aziz, and A. Biddah. 1997. “Rehabilitation of reinforced concrete frame connections using corrugated steel jacketing.” Struct. J. 94 (3): 282–294.
Hadi, M. N. S., and T. M. Tran. 2014. “Retrofitting nonseismically detailed exterior beam–column joints using concrete covers together with CFRP jacket.” Constr. Build. Mater. 63 (Jul): 161–173. https://doi.org/10.1016/j.conbuildmat.2014.04.019.
Hong Kong Buildings Department. 2004. Code of practice for structural use of concrete. Hong Kong: Hong Kong Buildings Department.
Karayannis, C. G., C. E. Chalioris, and G. M. Sirkelis. 2008. “Local retrofit of exterior RC beam–column joints using thin RC jackets—An experimental study.” Earthquake Eng. Struct. Dyn. 37 (5): 727–746. https://doi.org/10.1002/eqe.783.
Kaung, J. S., and H. F. Wong. 2011. “Effectiveness of horizontal stirrups in joint core for exterior beam-column joints with nonseismic design.” Procedia Eng. 14 (Jan): 3301–3307. https://doi.org/10.1016/j.proeng.2011.07.417.
Lam, E. S.-S., B. Li, Z. Xue, K.-T. Leung, and J. Y.-K. Lam. 2019. “Experimental studies on reinforced concrete interior beam-column joints strengthened by unsymmetrical chamfers.” Eng. Struct. 191 (Jul): 575–582. https://doi.org/10.1016/j.engstruct.2019.03.099.
Lam, E. S.-S., Z. Xue, S. Fang, and S. Masqood. 2020. “Interior beam column joints with nominal joint shear reinforcement versus unsymmetrical chamfers.” Eng. Struct. 220 (Oct): 110907. https://doi.org/10.1016/j.engstruct.2020.110907.
Leite, L., J. L. Bonet, L. Pallarés, P. F. Miguel, and M. A. Fernandez-Prada. 2012. “Behavior of RC slender columns under unequal eccentricities and skew angle loads at the ends.” Eng. Struct. 40 (Jul): 254–266. https://doi.org/10.1016/j.engstruct.2012.02.017.
Leite, L., J. L. Bonet, L. Pallarés, P. F. Miguel, and M. A. Fernández-Prada. 2013. “Experimental research on high strength concrete slender columns subjected to compression and uniaxial bending with unequal eccentricities at the ends.” Eng. Struct. 48 (Mar): 220–232. https://doi.org/10.1016/j.engstruct.2012.07.039.
Li, B., Q. Kai, and W. Xue. 2012. “Effects of eccentricity on the seismic rehabilitation performance of nonseismically detailed interior beamwide column joints.” J. Compos. Constr. 16 (5): 507–519. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000287.
Li, B., T.-C. Pan, and C. T. N. Tran. 2009. “Effect of axial compression load and eccentricity on seismic behavior of nonseismically detailed interior beam wide column joints.” J. Strut. Eng. 135 (7): 11.
Magenes, G., and S. Pampanin. 2004. “Seismic response of gravity-load design frame with masonry infills.” In Proc., 13th World Conf. on Earthquake Engineering. Vancouver, BC, Canada: Canadian Association for Earthquake Engineering.
Masi, A. 2003. “Seismic vulnerability assessment of gravity load designed R/C frames.” Bull. Earthquake Eng. 1 (3): 371–395. https://doi.org/10.1023/B:BEEE.0000021426.31223.60.
Mogili, S., J. S. Kuang, and R. Y. Huang. 2019. “Effects of beam–column geometry and eccentricity on seismic behaviour of RC beam–column knee joints.” Bull. Earthquake Eng. 17 (5): 2671–2686. https://doi.org/10.1007/s10518-019-00562-y.
Mou, B., Y. Liu, P. Wei, F. Zhao, W. Chenglong, and N. Ning. 2021. “Numerical investigation and design method of bolted beam-column joint panel with eccentricity in beam depths.” J. Constr. Steel Res. 180 (May): 106568. https://doi.org/10.1016/j.jcsr.2021.106568.
NZS (New Zealand Standards). 2006. The design of concrete structures. NZS 3101.1. Wellington, New Zealand: NZS.
Pimanmas, A., and P. Chaimahawan. 2010. “Shear strength of beam–column joint with enlarged joint area.” Eng. Struct. 32 (9): 2529–2545. https://doi.org/10.1016/j.engstruct.2010.04.021.
Priestley, M. 1997. “Displacement-based seismic assessment of reinforced concrete buildings.” J. Earthquake Eng. 1 (1): 157–192. https://doi.org/10.1142/S1363246997000088.
Santhi, H. M., G. Samuel Knight, and K. Muthumani. 2005. “Evaluation of seismic performance of gravity load designed reinforced concrete frames.” J. Perform. Constr. Facil. 19 (4): 277–282. https://doi.org/10.1061/(ASCE)0887-3828(2005)19:4(277).
Tsonos, A.-D. G. 2010. “Performance enhancement of R/C building columns and beam–column joints through shotcrete jacketing.” Eng. Struct. 32 (3): 726–740. https://doi.org/10.1016/j.engstruct.2009.12.001.
Tsonos, A. G. 2002. “Seismic repair of exterior R/C beam-to-column joints using two-sided and three-sided jackets.” Struct. Eng. Mech. 13 (1): 17–34. https://doi.org/10.12989/sem.2002.13.1.017.
Xue, Z., E. S. S. Lam, and S. Fang. 2021. “Load transfer mechanism of exterior beam-column joint with unsymmetrical chamfer.” Eng. Struct. 248: 113239.
Yap, S. L., and B. Li. 2011. “Experimental investigation of reinforced concrete exterior beam-column subassemblages for progressive collapse.” ACI Struct. J. 108 (5): 542–552.
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Published In
Journal of Structural Engineering
Volume 148 • Issue 8 • August 2022
Copyright
© 2022 American Society of Civil Engineers.
History
Received: Nov 3, 2021
Accepted: Mar 16, 2022
Published online: Jun 7, 2022
Published in print: Aug 1, 2022
Discussion open until: Nov 7, 2022
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