Effect of unequal spans on the collapse behavior of multi-story frames with reduced beam section connections
Zheng Tan,Wei-hui Zhong,Bao Meng,Li-min Tian,Yao Gao,Yu-hui Zheng,Hong-Chen Wang
Abstract
Following an internal column failure, adjacent double-span beams above the failed column will play a critical role in the load transfer and internal force redistribution within the remaining structure, and the span-to-depth ratios of double-span beams significantly influence the structural resistance capacity against progressive collapse. Most existing studies have focused on the collapse-resistant performances of single-story symmetric structures, whereas limited published works are available on the collapse resistances of multi-story steel frames with unequal spans. To this end, in this study, numerical models based on shell elements were employed to investigate the structural behavior of multi-story steel frames with unequal spans. The simulation models were validated using the previous experimental results obtained for single- and two-story steel frames, and the load–displacement responses and internal force development of unequal-span three-story steel frames under three cases were comprehensively analyzed. In addition, the specific contributions of the different mechanism resistances of unequal-span, double-span beams of each story were separated quantitatively using the energy equilibrium theory, with an aim to gain a deeper level of understanding of the load-resistance mechanisms in the unequal-span steel frames. The results showed that the axial and flexural mechanism resistances were determined by the span ratio and linear stiffness ratio of double-span beams, respectively.
Zheng Tan, Li-min Tian, Yao Gao, Yu-hui Zheng — School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
Wei-hui Zhong — 1)School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China 2)Key Laboratory of Structural Engineering and Earthquake Resistance, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
Bao Meng — 1)School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China 2)Key Laboratory of Structural Engineering and Earthquake Resistance, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China 3)Department of Civil and Environmental Engineering, National University of Singapore, 119077, Singapore
Hong-Chen Wang — China Northwest Architecture Design and Research Institute Co., Ltd, Xi'an 710018, China
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