Akademik Veri Yönetim Sistemi
THIN-WALLED STRUCTURES, cilt.49, sa.8, ss.984-996, 2011 (SCI-Expanded)
Seismic provisions for steel buildings present limiting width-thickness and slenderness ratios for bracing members, most of which were established based on experimental observations. A finite element study has been undertaken to evaluate these limits for pin-ended circular hollow section (CHS) steel braces. Uncertainties in modeling and quantification arise in the simulation of cyclic brace buckling. A finite element modeling procedure was developed and calibrated using existing experimental data. Sensitivity of the finite element analysis results to the uncertainties in modeling and quantification methods were studied in detail. A parametric study was conducted utilizing the calibrated modeling technique. Fifty four CHS brace models possessing different diameter-to-thickness ratios varying from 5 to 30 and slenderness ratios varying from 40 to 200 were analyzed. The effect of cyclic hardening modulus on the response of braces was explored. In all analysis, the models were subjected to reversed cyclic displacements up to ten times the yield displacement. In this paper, the results are presented in terms of the ductility level attained by the member at the onset of local buckling. It is shown that local buckling of the section is not only a function of the diameter-to-thickness ratio but is also influenced by the slenderness ratio of the member. Moreover, the amount of hardening modulus was found to affect the local buckling response significantly. The need to include this material property into seismic provisions is demonstrated. Finally, the hysteretic energy dissipated by the member was quantified for each displacement excursion. (C) 2011 Elsevier Ltd. All rights reserved.