Progressive collapse resistance of unsymmetrical steel sub-structure under a middle column-removal scenario. (15th June 2023)

• Record Type: Journal Article
• Authors: Yu, Peng; Huang, Xinheng; Li, Hongfei; Nie, Yongchao; He, Sheng
• Is Part Of: Journal of building engineering. Volume 69(2023)
• Publication Date: 2023-06-15
• Subjects: Progressive collapse -- Unsymmetrical steel structure -- Beam supporting transfer structure -- Span ratio -- Depth ratio; Building -- Periodicals; 690.05
• DOI: 10.1016/j.jobe.2023.105994
• Languages: English
• ISSNs: 2352-7102

Abstract

Abstract: This paper presents an investigation on progressive collapse resistance of a type of unsymmetrical steel sub-structure. The sub-structure which consists of box-beam, H-beam and tube column is extracted from the practical project. In order to examine the effect of the unequal geometrical parameters, three specimens with different span ratio of box-beam to H-beam and depth ratio of H-beam to box-beam were designed for Pushdown test. Moreover, a numerical analysis is carried out, wherein the finite element models are established by ABAQUS, and the validation is conducted by the comparison with experimental results. Furthermore, a B eam S upporting T ransfer S tructure (BSTS) is considered in parametric studies, aiming to further explore the influence of extra load resulting from BSTS on unsymmetrical structure. The experimental results indicate that the ratios expressed for the span and depth under different value can easily change the overall resistance of the unsymmetrical structure, especially in the F irst P eak L oad (FPL), U ltimate F ailure L oad (UFL). Regarding mechanical behavior of components, when the depth ratio is equal to 0.8, span ratio decreases from 1.5 to 1, the C atenary A ction (CA) of H-beam and F lexural A ction (FA) of box-beam display more sensitive to the variation of span ratio than other key results. Similarly, when the span ratio is equal to 1.5 depth ratio increases from 0.8 to 1, the FA of H-beam and CA of box-beam show more sensitive to the variation of depth ratio than other key results. Moreover, the UFLs of three specimens are observed as the ultimate load resistance in experiment, which is due to the development of the CA of beams and large residual resistance provided by the FA of box-beam. Ultimately, an advice of the span ratio and depth ratio for structure design is proposed. Highlights: The progressive collapse resistance of an unsymmetrical steel sub-structure under different span ratio and depth ratio are investigated through experimental studies. The load resistance from each beam in unsymmetrical sub-structure is quantified. The effect of beam supporting transfer structure on progressive resistance is discussed through numerical analysis. A suggestive design of the span ratio and depth ratio for structure is proposed.