Progressive Sidesway Collapse Analysis of Steel Moment-Resisting Frames Under Earthquake Excitations
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RESEARCH PAPER
Progressive Sidesway Collapse Analysis of Steel Moment‑Resisting Frames Under Earthquake Excitations Kourosh Mehdizadeh1 · Abbas Karamodin1 · Abbasali Sadeghi2 Received: 26 April 2018 / Accepted: 16 March 2020 © Shiraz University 2020
Abstract This paper deals with the assessment of seismic collapse capacities and the related collapse durations of steel momentresisting frames (MRFs). For this purpose, three prototypes of five-story steel structures are studied. These structures are special, intermediate and ordinary moment-resisting frames with high, medium and low ductility, respectively (SMRF, IMRF and OMRF). The structures have been designed in accordance with the Iranian codes. Furthermore, the deterioration effects of strength and stiffness for structural elements have been considered based on the results of reference experimental models. Next, using 22 pairs of far-field ground motion records proposed by FEMA P695 instruction, incremental dynamic analysis is conducted up to the dynamic instability of structures. Afterward, the collapse capacities of these structures are evaluated and compared with the fragility curves. Also, progressive sidesway collapse durations of the structures are estimated under the selected ground motion records. The results show that SMRF has larger collapse capacity than those of the other frames, and can diminish collapse probability by 33.4% and 54.6% compared to IMRF and OMRF, respectively. Moreover, the results reveal that sidesway collapse duration of SMRF is greater than IMRF and OMRF. Keywords Collapse capacity · Collapse duration · Steel moment-resisting frame · Ductility · Incremental dynamic analysis (IDA) · FEMA P695 instruction · Fragility curve · Progressive sidesway collapse
1 Introduction Prediction and prevention of seismic collapse of buildings is one of the main challenges of structural research. Although structural damage can occur at different performance levels, collapse is a catastrophic event in the construction industry, where casualties and financial loss can be overwhelming. Structural collapse appears as local and global collapse. In local collapse, usually some of the structural elements like beams, columns, braces and walls are damaged and some parts of the structure are destroyed. Local collapse could * Kourosh Mehdizadeh [email protected] Abbas Karamodin a‑[email protected] Abbasali Sadeghi [email protected] 1
Department of Civil Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
Department of Civil Engineering, Mashhad Branch, Islamic Azad University, Mashhad, Iran
2
progress across the whole structure, affecting one element after the other (Progressive Collapse) (Kazantzi et al. 2014; Fereshtehnejad et al. 2016). In global collapse, the whole structure loses its serviceability. A sidesway collapse is a type of global collapse in which the relative displacement of one or more stories is much larger than the others. Therefore, collapse sometimes occurs under the influence of secondary moment (P − Δ) ef
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