Design and Optimization of Cold-Formed Steel Sections in Bolted Moment Connections Considering Bimoment
Publication: Journal of Structural Engineering
Volume 146, Issue 8
Abstract
The load transfer mechanism in cold-formed steel (CFS) bolted moment connections is mainly through the bolt group in the web of beam elements, which may lead to relatively large bimoment and warping deformations. While the bimoment effects can be considered in the Direct Strength Method (DSM), ignoring the fact that the bolt-group length in the conventional design process can lead to nonconservative solutions. This paper presents an alternative analytical design approach using Eurocode 3 (EC3) effective width method to determine the ultimate flexural strength of CFS bolted moment connections by considering bimoment effects. The results compare very well with previously published experimental test data as well as detailed finite-element models developed in this study. It is shown that a short bolt-group length may lead to up to 25% reduction in the flexural strength of the CFS bolted connections. However, a longer bolt-group length generally results in a moment capacity almost equal to the flexural strength of the CFS channel section. Shape optimization is then conducted using a genetic algorithm (GA) to improve the flexural capacity of the connections by taking into account the bimoment effects. The main design variables are considered to be the relative CFS beam cross-sectional dimensions, while the plate slenderness and dimension limits suggested by EC3 as well as a number of manufacturing and practical end-use constraints are incorporated as design constraints. It is found that, compared with standard cross-sectional dimensions, the optimized sections can improve the flexural strength by as much as 36% for a bolt-group length equal to the depth of beam element.
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Data Availability Statement
Some or all data, models, or code generated or used during the study are available from the corresponding author by request. This data includes material properties, geometric imperfections, connector behavior, and optimization.
Acknowledgments
This research was supported by the Engineering and Physical Sciences Research Council (EPSRC) Grants EP/L019116/1. The second author was also supported by EPSRC Doctoral Scholarship Grant 1625179.
References
AISI (American Iron and Steel Institute). 2016. North American specification for the design of cold-formed steel structural members. AISI S100. Washington, DC: AISI.
Alberdi, R., P. Murren, and K. Khandelwal. 2015. “Connection topology optimization of steel moment frames using metaheuristic algorithms.” Eng. Struct. 100 (Oct): 276–292. https://doi.org/10.1016/j.engstruct.2015.06.014.
Bagheri Sabbagh, A., M. Petkovski, K. Pilakoutas, and R. Mirghaderi. 2012. “Experimental work on cold-formed steel elements for earthquake resilient moment frame buildings.” Eng. Struct. 42 (1): 371–386. https://doi.org/10.1016/j.engstruct.2012.04.025.
Bel Hadj Ali, N., M. Sellami, A.-F. Cutting-Decelle, and J.-C. Mangin. 2009. “Multi-stage production cost optimization of semi-rigid steel frames using genetic algorithms.” Eng. Struct. 31 (11): 2766–2778. https://doi.org/10.1016/j.engstruct.2009.07.004.
Blum, H. B., and K. J. R. Rasmussen. 2019. “Experimental investigation of long-span cold-formed steel double channel portal frames.” J. Constr. Steel Res. 155 (Apr): 316–330. https://doi.org/10.1016/j.jcsr.2018.11.020.
Bučmys, Ž., A. Daniūnas, J.-P. Jaspart, and J.-F. Demonceau. 2018. “A component method for cold-formed steel beam-to-column bolted gusset plate joints.” Thin Walled Struct. 123 (Feb): 520–527.
CEN (European Comittee for Standardization). 2005. Eurocode 3: Design of steel structures, Part 1.3: General rules—Supplementary rules for cold formed members and sheeting. Brussels: CEN.
CEN (European Comittee for Standardization). 2006. Eurocode 3: Design of steel structures, Part 1–5: Plated structural elements. Brussels: CEN.
Chung, K. F., and L. Lau. 1999. “Experimental investigation on bolted moment connections among cold formed steel members.” Eng. Struct. 21 (10): 898–911. https://doi.org/10.1016/S0141-0296(98)00043-1.
Deb, K. 2001. Multi-objective optimization using evolutionary algorithms. Chichester, UK: Wiley.
Dubina, D., A. Stratan, and Z. Nagy. 2009. “Full-scale tests on cold-formed steel pitched-roof portal frames with bolted joints.” Adv. Steel Constr. 5 (2): 175–194.
Elkersh, I. 2010. “Experimental investigation of bolted cold formed steel frame apex connections under pure moment.” Ain Shams Eng. J. 1 (1): 11–20. https://doi.org/10.1016/j.asej.2010.09.002.
Erbatur, F., O. Hasançebi, İ. Tütüncü, and H. Kılıç. 2000. “Optimal design of planar and space structures with genetic algorithms.” Comput. Struct. 75 (2): 209–224. https://doi.org/10.1016/S0045-7949(99)00084-X.
Kirk, P. 1986. “Design of a cold-formed section portal frame building system.” In Proc., 8th Int. Speciality Conf. on Cold-formed Steel Structures, 259. St. Louis, MO: Univ. of Missouri-Rolla.
Lim, J. B. P., G. J. Hancock, G. C. Clifton, C. H. Pham, and R. Das. 2016. “DSM for ultimate strength of bolted moment-connections between cold-formed steel channel members.” J. Constr. Steel Res. 117 (Feb): 196–203. https://doi.org/10.1016/j.jcsr.2015.10.005.
Lim, J. B. P., and D. A. Nethercot. 2003. “Ultimate strength of bolted moment-connections between cold-formed steel members.” Thin Walled Struct. 41 (11): 1019–1039. https://doi.org/10.1016/S0263-8231(03)00045-4.
Lim, J. B. P., and D. A. Nethercot. 2004a. “Finite element idealization of a cold-formed steel portal frame.” J. Struct. Eng. 130 (1): 78–94. https://doi.org/10.1061/(ASCE)0733-9445(2004)130:1(78).
Lim, J. B. P., and D. A. Nethercot. 2004b. “Stiffness prediction for bolted moment-connections between cold-formed steel members.” J. Constr. Steel Res. 60 (1): 85–107. https://doi.org/10.1016/S0143-974X(03)00105-6.
Lwin, K., R. Qu, and G. Kendall. 2014. “A learning-guided multi-objective evolutionary algorithm for constrained portfolio optimization.” Appl. Soft Comput. 24 (Nov): 757–772. https://doi.org/10.1016/j.asoc.2014.08.026.
Mathworks. 2015. MATLAB R2015b. Natick, MA: Mathworks.
Meza, F. J., J. Becque, and I. Hajirasouliha. 2020. “Experimental study of cold-formed steel built-up columns.” Thin Walled Struct. 149: 106291. https://doi.org/10.1016/j.tws.2019.106291.
Mojtabaei, S. M., M. Z. Kabir, I. Hajirasouliha, and M. Kargar. 2018. “Analytical and experimental study on the seismic performance of cold-formed steel frames.” J. Constr. Steel Res. 143 (Apr): 18–31. https://doi.org/10.1016/j.jcsr.2017.12.013.
Mojtabaei, S. M., J. Ye, and I. Hajirasouliha. 2019. “Development of optimum cold-formed steel beams for serviceability and ultimate limit states using Big Bang-Big Crunch optimization.” Eng. Struct. 195 (Sep): 172–181. https://doi.org/10.1016/j.engstruct.2019.05.089.
Öztürk, F., and S. Pul. 2015. “Experimental and numerical study on a full scale apex connection of cold-formed steel portal frames.” Thin Walled Struct. 94 (Sep): 79–88.
Pathan, M. V., S. Patsias, and V. L. Tagarielli. 2018. “A real-coded genetic algorithm for optimizing the damping response of composite laminates.” Comput. Struct. 198 (Mar): 51–60. https://doi.org/10.1016/j.compstruc.2018.01.005.
Pezeshk, S., C. V. Camp, and D. Chen. 2000. “Design of nonlinear framed structures using genetic optimization.” J. Struct. Eng. 126 (3): 382–388. https://doi.org/10.1061/(ASCE)0733-9445(2000)126:3(382).
Phan, D. T., J. B. P. Lim, T. T. Tanyimboh, and W. Sha. 2013. “An efficient genetic algorithm for the design optimization of cold-formed steel portal frame buildings.” Steel Compos. Struct. Int. J. 15 (5): 519–538. https://doi.org/10.12989/scs.2013.15.5.519.
Phan, D. T., S. M. Mojtabaei, I. Hajirasouliha, J. Ye, and J. B. P. Lim. 2019. “Coupled element and structural level optimisation framework for cold-formed steel frames.” J. Constr. Steel Res. 105867. https://doi.org/10.1016/j.jcsr.2019.105867.
Ramires, F. B., S. A. L. de Andrade, P. C. G. da Silva Vellasco, and L. R. O. de Lima. 2012. “Genetic algorithm optimization of composite and steel endplate semi-rigid joints.” Eng. Struct. 45 (Dec): 177–191. https://doi.org/10.1016/j.engstruct.2012.05.051.
Rinchen, and K. J. Rasmussen. 2019a. “Behaviour and modelling of connections in cold-formed steel single C-section portal frames.” Thin Walled Struct. 143 (Oct): 106233.
Rinchen, and K. J. Rasmussen. 2019b. “Numerical modelling of cold-formed steel single C-section portal frames.” J. Constr. Steel Res. 158 (Jul): 143–155.
Rinchen, K. J. Rasmussen, and H. Zhang. 2019. “Design of cold-formed steel single C-section portal frames.” J. Constr. Steel Res. 162 (Nov): 105722.
Sabbagh, A. B., R. Mirghaderi, M. Petkovski, and K. Pilakoutas. 2010. “An integrated thin-walled steel skeleton structure (two full scale tests).” J. Constr. Steel Res. 66 (3): 470–479. https://doi.org/10.1016/j.jcsr.2009.10.007.
Sabbagh, A. B., M. Petkovski, K. Pilakoutas, and R. Mirghaderi. 2013. “Cyclic behaviour of bolted cold-formed steel moment connections: FE modelling including slip.” J. Constr. Steel Res. 80 (Jan): 100–108. https://doi.org/10.1016/j.jcsr.2012.09.010.
Schafer, B. W. 2006. “CUFSM version 3.12.” Accessed September 1 2007. http://www.ce.jhu.edu/bschafer/cufsm/.
Schafer, B. W., and T. Peköz. 1998. “Computational modeling of cold-formed steel: Characterizing geometric imperfections and residual stresses.” J. Constr. Steel Res. 47 (3): 193–210. https://doi.org/10.1016/S0143-974X(98)00007-8.
Serror, M. H., E. M. Hassan, and S. A. Mourad. 2016. “Experimental study on the rotation capacity of cold-formed steel beams.” J. Constr. Steel Res. 121 (Jun): 216–228. https://doi.org/10.1016/j.jcsr.2016.02.005.
Vlasov, V. Z. 1961. Thin-walled elastic beams.
Walker, A. C. 1975. Design and analysis of cold-formed sections. New York: Halsted Press.
Wang, B., G. L. Bosco, B. P. Gilbert, H. Guan, and L. H. Teh. 2016. “Unconstrained shape optimisation of singly-symmetric and open cold-formed steel beams and beam-columns.” Thin Walled Struct. 104 (Jul): 54–61. https://doi.org/10.1016/j.tws.2016.03.007.
Wong, M. F., and K. F. Chung. 2002. “Structural behaviour of bolted moment connections in cold-formed steel beam-column sub-frames.” J. Constr. Steel Res. 58 (2): 253–274. https://doi.org/10.1016/S0143-974X(01)00044-X.
Ye, J., J. Becque, I. Hajirasouliha, S. M. Mojtabaei, and J. B. P. Lim. 2018a. “Development of optimum cold-formed steel sections for maximum energy dissipation in uniaxial bending.” Eng. Struct. 161: 55–67. https://doi.org/10.1016/j.engstruct.2018.01.070.
Ye, J., S. M. Mojtabaei, and I. Hajirasouliha. 2018b. “Local-flexural interactive buckling of standard and optimised cold-formed steel columns.” J. Constr. Steel Res. 144 (May): 106–118. https://doi.org/10.1016/j.jcsr.2018.01.012.
Ye, J., S. M. Mojtabaei, and I. Hajirasouliha. 2019. “Seismic performance of cold-formed steel bolted moment connections with bolting friction-slip mechanism.” J. Constr. Steel Res. 156: 122–136. https://doi.org/10.1016/j.jcsr.2019.01.013.
Ye, J., S. M. Mojtabaei, I. Hajirasouliha, and K. Pilakoutas. 2020. “Efficient design of cold-formed steel bolted-moment connections for earthquake resistant frames.” Thin-Walled Struct 150 (May): 1–8.
Ye, J., S. M. Mojtabaei, I. Hajirasouliha, P. Shepherd, and K. Pilakoutas. 2018c. “Strength and deflection behaviour of cold-formed steel back-to-back channels.” Eng. Struct. 177 (Dec): 641–654. https://doi.org/10.1016/j.engstruct.2018.09.064.
Yeniay, O. 2005. “Penalty function methods for constrained optimization with genetic algorithms.” Math. Comput. Appl. 10 (1): 45–56. https://doi.org/10.3390/mca10010045.
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Published In
Journal of Structural Engineering
Volume 146 • Issue 8 • August 2020
Copyright
©2020 American Society of Civil Engineers.
History
Received: Oct 14, 2019
Accepted: Feb 25, 2020
Published online: May 25, 2020
Published in print: Aug 1, 2020
Discussion open until: Oct 25, 2020
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