Improved seismic resilience of existing steel moment frame by built-in continuous columns. (May 2023)

• Record Type: Journal Article
• Authors: Li, Cheng-Yu; Bai, Ru-Ning; Zhang, Hong-Tai; Jia, Liang-Jiu
• Is Part Of: Journal of constructional steel research. Volume 204(2023)
• Publication Date: 2023-05
• Subjects: Continuous column -- Deterioration -- Stiffness -- Drift concentration -- Collapse control -- Seismic resilience; Steel, Structural -- Periodicals; Building, Iron and steel -- Periodicals; Acier de construction -- Périodiques; Construction métallique -- Périodiques; 624.1821
• DOI: 10.1016/j.jcsr.2023.107849
• Languages: English
• ISSNs: 0143-974X

Abstract

Abstract: A seismic resilience strategy of retrofitting the existing columns of frame structures into built-in continuous columns (BCCs) hinged to the main frame is presented in this paper. The continuous columns provide vertical continuous stiffness to adjust the structural deformation distribution achieving collapse control. This study retrofits three 5-, 7- and 9-story prototype steel moment frames (SMFs) through external continuous columns (ECCs) or BCCs. In addition, effects of strength and stiffness deterioration on the seismic response of the SMFs are also considered. Results from pushover and incremental dynamic analysis show that the ECCs and BCCs can both mitigate structural displacement concentration. With a performance target of plasticity hinge ratio up to 50% for the main frame, when the stiffness demand is satisfied, the inter-story drift concentration factor of the BCC frame is always smaller than that of the ECC one. It indicates that the inter-story deformation distribution of the BCC frame is more uniform under the premise of satisfying the target collapse resistance performance. Highlights: A seismic resilience strategy to retrofit steel moment frame structures using built-in continuous columns (BCCs) proposed. FE models considering stiffness and strength deterioration established for pushover and incremental dynamic analyses. Critical performance indices proposed to determine optimal stiffness for continuous columns. A lower bound column stiffness of 3.0 for the BCCs steel moment frame structures presented. The proposed BCCs steel moment frame structures show excellent seismic collapse resilience.