TY - JOUR
T1 - Dual system design for a low-ductility concentrically braced frame with a reserve moment frame
AU - Bradley, Cameron R.
AU - Fahnestock, Larry A.
AU - Hines, Eric M.
N1 - Funding Information:
This study was supported by the National Science Foundation (Grant No. CMMI-1207976) and the American Institute of Steel Construction.
Funding Information:
In particular, the proposed CBDF design criteria were derived from the results of numerical studies presented by Bradley [5] , and Bradley et al. [7] , where the dynamic collapse probabilities of 2 conventional and 216 parameterized variations of a prototype SFRS were assessed through nonlinear simulations of structural response to ground motion excitations. The numerical models were constructed using a combination of distributed-plasticity and concentrated-plasticity elements to simulate nonlinear member and connection behaviors including brace and column buckling, and effects, low-cycle fatigue degradation, and weld fracture. This approach was derived from the aggregation of relevant modeling techniques discussed in the literature and has been shown to closely predict experimental results of full-scale tests on three-story OCBF and R3CBF systems [8–10] . Following the methodology outlined in the FEMA P695 report [11] , collapse performance of the models was evaluated through the incremental dynamic analysis (IDA) procedure defined by Vamvatsikos and Cornell [12] . Additionally, variations in collapse probabilities were quantified with respect to five design parameters using an analysis of variances (ANOVA) model. Ultimately, this modeling framework represents the culmination of a decade-long collaboration between researchers at the University of Illinois at Urbana-Champaign, Tufts University, and École Polytechnique de Montréal (EPM) under the National Science Foundation (NSF) project entitled Reserve Capacity in New and Existing Low Ductility Steel Braced Frames (Grant No. CMMI-1207976).
Publisher Copyright:
© 2021 Institution of Structural Engineers
PY - 2021/12
Y1 - 2021/12
N2 - To address shortcomings of the moderate-seismic design philosophy currently implemented in the United States, this paper proposes design criteria for a Concentrically Braced Dual Frame (CBDF). In contrast to existing low-ductility Concentrically Braced Frame (CBF) systems, such as R=3 CBF (R3CBF) and Ordinary Concentrically Braced Frame (OCBF) systems, the proposed CBDF design approach explicitly considers the strength and integrity of the post-elastic, degraded (reserve) system. Specifically, the CBDF is defined to consist of a stiff low-ductility primary concentrically braced frame (PCBF) supplemented by a flexible, distributed reserve moment-resisting frame (RMRF). Relative to the R3CBF and OCBF systems, the proposed CBDF system achieves superior collapse performance without the need for costly ductility detailing requirements or substantial changes to traditional seismic design provisions. Consequently, the CBDF system is proposed as a practical, reliable, and cost-effective design alternative to R3CBF and OCBF systems.
AB - To address shortcomings of the moderate-seismic design philosophy currently implemented in the United States, this paper proposes design criteria for a Concentrically Braced Dual Frame (CBDF). In contrast to existing low-ductility Concentrically Braced Frame (CBF) systems, such as R=3 CBF (R3CBF) and Ordinary Concentrically Braced Frame (OCBF) systems, the proposed CBDF design approach explicitly considers the strength and integrity of the post-elastic, degraded (reserve) system. Specifically, the CBDF is defined to consist of a stiff low-ductility primary concentrically braced frame (PCBF) supplemented by a flexible, distributed reserve moment-resisting frame (RMRF). Relative to the R3CBF and OCBF systems, the proposed CBDF system achieves superior collapse performance without the need for costly ductility detailing requirements or substantial changes to traditional seismic design provisions. Consequently, the CBDF system is proposed as a practical, reliable, and cost-effective design alternative to R3CBF and OCBF systems.
KW - Building structures
KW - Concentrically Braced Frames
KW - Design philosophy
KW - Earthquake-resistant design
KW - Low-ductility systems
KW - Moderate-seismic regions
KW - Reserve capacity
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U2 - 10.1016/j.istruc.2021.09.009
DO - 10.1016/j.istruc.2021.09.009
M3 - Article
AN - SCOPUS:85116038943
SN - 2352-0124
VL - 34
SP - 3315
EP - 3328
JO - Structures
JF - Structures
ER -