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On the quantification of seismic performance factors of Chevron Knee Bracings, in steel structures

Farahi, M ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.engstruct.2012.06.026
  3. Abstract:
  4. As a matter of fact, it is necessary to have the values of Response Modification Factor R, Over-strength Factor Ω0, and Deflection Amplification Factor Cd in order to design seismic-force-resisting systems according to design and loading codes. This study is intended to evaluate these factors for a structural lateral bracing system called Chevron Knee Bracing (CKB). In this type of bracing, the knee elements assist the system to dissipate energy through the formation of plastic flexural and/or shear hinges within the presented bracing system. The approach utilized in this study is according to FEMA P695 based on low probability of structural collapse and involves nonlinear static and dynamic analyses. Over-strength and ductility of this type of bracing is investigated through performing nonlinear static analyses. Conducting Incremental Dynamic Analyses (IDA), Collapse Margin Ratios (CMRs) of the defined archetypes model are achieved and modified to obtain an Adjusted Collapse Margin Ratio, ACMR for each archetype. The values of calculated ACMRs are compared with the accepted values proposed by FEMA P695 in which the total system collapse uncertainty is considered to prove the validity of presumed seismic performance factors of CKB systems
  5. Keywords:
  6. Collapse margin ratio ; Incremental dynamic analysis ; Seismic performance factor ; Amplification factors ; Bracing systems ; Chevron knee bracing ; Lateral bracing ; Loading codes ; Low probability ; Non-linear static analysis ; Nonlinear statics ; Overstrength ; Response modification factors ; Seismic performance ; Structural collapse ; System collapse ; Dynamic analysis ; Loading ; Seismic waves ; Static analysis ; Braces (for limbs and joints) ; Dynamic response ; Energy dissipation ; Performance assessment ; Seismic design ; Seismic response ; Steel structure ; Structural analysis ; Uncertainty analysis
  7. Source: Engineering Structures ; Volume 46 , 2013 , Pages 155-164 ; 01410296 (ISSN)
  8. URL: http://www.sciencedirect.com/science/article/pii/S0141029612003355