Revealing the phase transition of steel frames with CFST columns during progressive collapse process from a thermodynamic perspective

• Published in: Journal of Building Engineering 2024-08, Vol.90, p.109448, Article 109448
• Main Authors: Shen, Zijie, Zhang, Yu, Zhou, Guangchun, Guo, Lanhui, Wu, Zhenyu
• Format: Article
• Language: English
• Subjects: CFST column; Progressive collapse; Steel frame; Stressing state; Thermodynamic
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2024.109448

Progressive collapse is a standard failure pattern of steel frames, which researchers expect to analyze quantitatively. However, the existing resist progressive collapse analysis methods based on empirical or reliability theories make it challenging to give quantitative results. Based on the stressing state theory, this work attempts to reveal the phase transition loads during the progressive collapse process from a thermodynamic perspective. Firstly, a 1/3-scale 4-bay steel frame with CFST columns is selected as a case study and equated to a thermodynamic/complex system, and its deformation distribution is transformed into state variables. Matrices (Modes) and Hamiltonians (Characteristic parameters) are constructed to describe the steel frame's stressing state in part or overall. The approximate phase transition loads can be detected by applying the clustering analysis criterion. Further, the phase transition loads can be verified from the renormalization perspective by comparing the Test-based and FEM-based phase transition loads. The EPB points can be directly used as a design reference. In summary, this work reveals the stable phase transition loads of steel frames from the thermodynamic perspective for a case study. Also, it enriches the theory and methodology of thermodynamic-based structural failure studies. [Display omitted] •Revealed the phase transition loads of steel frames with CFST columns from a thermodynamic perspective.•Construct the Matrices and Hamiltonians to characterize the stressing state of steel frames.•Verify the phase transition loads from the renormalization perspective and compare the Test-based and FEM-based results.•Propose that EPB points can be used as a reference for steel frame designing.