Steel and Composite Structures

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

Lateral torsional buckling of steel I-beams: Effect of initial geometric imperfection

  • Bas, Selcuk (Department of Civil Engineering, Faculty of Engineering, Bartin University)
  • Received : 2018.11.07
  • Accepted : 2019.03.08
  • Published : 2019.03.10
⟨ Previous Next ⟩

Abstract

In the current study, the influence of the initial lateral (sweep) shape and the cross-sectional twist imperfection on the lateral torsional buckling (LTB) response of doubly-symmetric steel I-beams was investigated. The material imperfection (residual stress) was not considered. For this objective, standard European IPN 300 beam with different unbraced span was numerically analyzed for three imperfection cases: (i) no sweep and no twist (perfect); (ii) three different shapes of global sweep (half-sine, full-sine and full-parabola between the end supports); and (iii) the combination of three different sweeps with initial sinusoidal twist along the beam. The first comparison was done between the results of numerical analyses (FEM) and both a theoretical solution and the code lateral torsional buckling formulations (EC3 and AISC-LRFD). These results with no imperfection effects were then separately compared with three different shapes of global sweep and the presence of initial twist in these sweep shapes. Besides, the effects of the shapes of initial global sweep and the inclusion of sinusoidal twist on the critical buckling load of the beams were investigated to unveil which parameter was considerably effective on LTB response. The most compatible outcomes for the perfect beams was obtained from the AISC-LRFD formulation; however, the EC-3 formulation estimated the $P_{cr}$ load conservatively. The high difference from the EC-3 formulation was predicted to directly originate from the initial imperfection reduction factor and high safety factor in its formulation. Due to no consideration of geometric imperfection in the AISC-LFRD code solution and the theoretical formulation, the need to develop a practical imperfection reduction factor for AISC-LRFD and theoretical formulation was underlined. Initial imperfections were obtained to be more influential on the buckling load, as the unbraced length of a beam approached to the elastic limit unbraced length ($L_r$). Mode-compatible initial imperfection shapes should be taken into account in the design and analysis stages of the I-beam to properly estimate the geometric imperfection influence on the $P_{cr}$ load. Sweep and sweep-twist imperfections led to 10% and 15% decrease in the $P_{cr}$ load, respectively, thus; well-estimated sweep and twist imperfections should considered in the LTB of doubly-symmetric steel I-beams.

Keywords

References

  1. ABAQUS (2017), Standard User's Manual; Dassault Systemes, Waltham, MA, USA.
  2. Aguero, A., Pallares, L. and Pallares, F.J. (2015), "Equivalent geometric imperfection definition in steel structures sensitive to flexural and/or torsional buckling due to compression", Eng. Struct., 96, 160-177. https://doi.org/10.1016/j.engstruct.2015.03.065
  3. AISC-LRFD (2016), Specification for structural steel buildings; American Institute of Steel Construction, Chicago, IL, USA.
  4. AS4100-1998 (2016), Steel structures; Standards Association of Australia, Sydney, Australia.
  5. Aydin, R., Gunaydin, A. and Kirac, N. (2015), "On the evaluation of critical lateral buckling loads of prismatic steel beams", Steel Compos. Struct., Int. J., 18(3), 603-621. https://doi.org/10.12989/scs.2015.18.3.603
  6. Bas, S., Kalkan, I. and Aykac, S. (2016), "The influence of web distortion of doubly-symmetric steel I-beam on elastic and plastic slenderness limits", Istanbul Bridge Conference 2016, Istanbul, Turkey.
  7. Beyer, A., Boissonnade, N., Khelil, A. and Bureau, A. (2018), "Influence of assumed geometric and material imperfections on the numerically determined ultimate resistance of hot-rolled Ushaped steel members", J. Constr. Steel Res., 147, 103-115. https://doi.org/10.1016/j.jcsr.2018.03.021
  8. Chen, G., Zhang, H., Rasmussen, K.J.R. and Fan, F. (2016), "Modeling geometric imperfections for reticulated shell structures using random field theory", Eng. Struct., 126, 481-489. https://doi.org/10.1016/j.engstruct.2016.08.008
  9. Dahmani, L. and Boudjemia, A. (2014), "Lateral torsional buckling response of steel beam with different boundary conditions and loading", Strength Mater., 46(3), 429-432. https://doi.org/10.1007/s11223-014-9565-3
  10. Dou, C. and Pi, Y.-L. (2016), "Effects of geometric imperfections on flexural buckling resistance of laterally braced columns", J. Struct. Eng., 142(9), 04016048. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001508
  11. Dou, C., Pi, Y.-L. and Gao, W. (2018), "Restraining requirements for lateral elastic-plastic buckling of columns accounting for random imperfections", Eng. Struct., 171, 260-268. https://doi.org/10.1016/j.engstruct.2018.05.087
  12. Eurocode-3 (EC3) (2005), EN 1993-1-1: Design of steel structures - Part 1-1: General rules and rules for buildings European Committee for Standardization; Brussels, Belgium.
  13. Hassan, R. and Mohareb, M. (2015), "Distortional lateral torsional buckling for simply supported beams with web cleats", Can. J. Civil Eng., 42(12), 1091-1103. https://doi.org/10.1139/cjce-2015-0084
  14. Kala, Z. (2013), "Elastic lateral-torsional buckling of simply supported hot-rolled steel I-beams with random imperfections", Procedia Eng., 57, 504-514. https://doi.org/10.1016/j.proeng.2013.04.065
  15. Kala, Z. (2017), "Stability of Von-Misses Truss with initial random imperfections", Procedia Eng., 172, 473-480. https://doi.org/10.1016/j.proeng.2017.02.055
  16. Kala, Z. and Vales, J. (2017), "Global sensitivity analysis of lateral-torsional buckling resistance based on finite element simulations", Eng. Struct., 134, 37-47. https://doi.org/10.1016/j.engstruct.2016.12.032
  17. Kala, Z., Vales, J. and Martinasek, J. (2017), "Inelastic finite element analysis of lateral buckling for beam structures", Procedia Eng., 172, 481-488. https://doi.org/10.1016/j.proeng.2017.02.056
  18. Kalkan, I. and Buyukkaragoz, A. (2012), "A numerical and analytical study on distortional buckling of doubly-symmetric steel I-beams", J. Constr. Steel Res., 70, 289-297. https://doi.org/10.1016/j.jcsr.2011.06.006
  19. Kovesdi, B., Mecseri, B.J. and Dunai, L. (2018), "Imperfection analysis on the patch loading resistance of girders with open section longitudinal stiffeners", Thin-Wall. Struct., 23, 195-205. https://doi.org/10.1016/j.tws.2017.11.030
  20. Kus, J. (2015), "Lateral-torsional buckling steel beams with simultaneously tapered flanges and web", Steel Compos. Struct., Int. J., 19(4), 897-916 https://doi.org/10.12989/scs.2015.19.4.897
  21. Lei, J.-s. and Li, L.-y. (2017), "Combined web distortional and lateral-torsional buckling of partially restrained I-section beams", Int. J. Mech. Sci., 131-132, 107-112. https://doi.org/10.1016/j.ijmecsci.2017.06.057
  22. Mirzaie, F., Myers, A.T., Jay, A., Mahmoud, A., Torabian, S., Smith, E. and Schafer, B.W. (2018), "Imperfection measurements to predict buckling behavior of slender steel tubes", Thin-Wall. Struct., 123, 270-281. https://doi.org/10.1016/j.tws.2017.11.016
  23. Mohebkhah, A. (2004), "The moment-gradient factor in lateral-torsional buckling on inelastic castellated beams", J. Constr. Steel Res., 60(10), 1481-1494. https://doi.org/10.1016/j.jcsr.2004.02.002
  24. Naderian, H.R., Ronagh, H.R. and Azhari, M. (2014), "Elastic distortional buckling of doubly symmetric steel I-section beams with slender webs", Thin-Wall. Struct., 84, 289-301. https://doi.org/10.1016/j.tws.2014.05.010
  25. Nguyen, T.T., Chan, T.M. and Mottram, J.T. (2013), "Influence of boundary conditions and geometric imperfections on lateral-torsional buckling resistance of a pultruded FRP I-beam by FEA", Compos. Struct., 100, 233-242. https://doi.org/10.1016/j.compstruct.2012.12.023
  26. Pezeshky, P. and Mohareb, M. (2014), "Distortional theory for the analysis of wide flange steel beams", Eng. Struct., 75, 181-196. https://doi.org/10.1016/j.engstruct.2014.05.024
  27. Roy, J., Tremblay, R. and Leger, P. (2015), "Torsional effects in symmetrical steel buckling restrained braced frames: evaluation of seismic design provisions", Earthq. Struct., Int. J., 8(2), 423-442. https://doi.org/10.12989/eas.2015.8.2.423
  28. Sonck, D. and Belis, J. (2015), "Lateral-torsional buckling resistance of cellular beams", J. Constr. Steel Res., 105, 119-128. https://doi.org/10.1016/j.jcsr.2014.11.003
  29. SSRC (Structural Stability Research Council) (2010), Guide to Stability Design Criteria for Metal Structures; (Edited by R.D. Ziemian), John Wiley & Sons, USA.
  30. Subramanian, L. and White, D.W. (2017), "Flexural resistance of longitudinally stiffened I-girders. II: LTB and FLB limit states", J. Bridge Eng., 22(1), 04016100. https://doi.org/10.1061/(ASCE)BE.1943-5592.0000976
  31. Subramanian, L. and White, D.W. (2017), "Reassessment of the lateral torsional buckling resistance of I-section members: uniform-moment studies", J. Struct. Eng., 143(3), 04016194. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001686
  32. Tankova, T., Martins, J.P., Simoes da Silva, L., Marques, L., Craveiro, H.D. and Santiago, A. (2018), "Experimental lateraltorsional buckling behaviour of web tapered I-section steel beams", Eng. Struct., 168, 355-370. https://doi.org/10.1016/j.engstruct.2018.04.084
  33. Thai, H.-T., Kim, S.-E. and Kim, J. (2017), "Improved refined plastic hinge analysis accounting for local buckling and lateraltorsional buckling", Steel Compos. Struct., Int. J., 24(3), 339-349.
  34. Tohidi, S. and Sharifi, Y. (2018), "Flexural distortional strength of steel beams determined by finite-element modelling", Proceedings of the Institution of Civil Engineers - Structures and Buildings, 171(3), 195-202. https://doi.org/10.1680/jstbu.14.00052
  35. Unterweger, H., Taras, A., Loschan, S. and Kettler, M. (2017), "Influence of imperfections on the stability of beams with intermediate flexible supports", J. Constr. Steel Res., 136, 140-148. https://doi.org/10.1016/j.jcsr.2017.05.008
  36. Winkler, R., Kindmann, R. and Knobloch, M. (2017), "Lateral torsional buckling behaviour of steel beams-on the influence of the structural system", Structures, 11, 178-188. https://doi.org/10.1016/j.istruc.2017.05.007
  37. Yang, B., Xiong, G., Ding, K., Nie, S., Zhang, W., Hu, Y. and Dai, G. (2016), "Experimental and numerical studies on lateraltorsional buckling of GJ structural steel beams under a concentrated loading condition", Int. J. Struct. Stabil. Dyn., 16(1), 1640004. https://doi.org/10.1142/S0219455416400046
  38. Zhou, W.-B., Li, S.-J. and Yan, W.-J. (2016), "Practical formulas towards distortional buckling failure analysis for steel-concrete composite beams", The Struct. Des. Tall Special Build., 25(18), 1055-1072. https://doi.org/10.1002/tal.1297
  39. Zirakian, T. (2008), "Elastic distortional buckling of doubly symmetric I-shaped flexural members with slender webs", Thin-Wall. Struct., 46(5), 466-475. https://doi.org/10.1016/j.tws.2007.11.001
  40. Zirakian, T. and Zhang, J. (2012), "Elastic distortional buckling of singly symmetric I-shaped flexural members with slender webs", Int. J. Struct. Stabil. Dyn., 12(2), 359-376. https://doi.org/10.1142/S0219455412500071

Cited by

  1. Effect of residual stress and geometric imperfection on the strength of steel box girders vol.34, pp.3, 2019, https://doi.org/10.12989/scs.2020.34.3.423
  2. Simplified approach to estimate the lateral torsional buckling of GFRP channel beams vol.77, pp.4, 2019, https://doi.org/10.12989/sem.2021.77.4.523