Pseudo-dynamic test of a full-scale CFT/BRB frame-Part II: Seismic performance of buckling-restrained braces and connections

• Published in: Earthquake engineering & structural dynamics 2008-06, Vol.37 (7), p.1099-1115
• Main Authors: Tsai, Keh-Chyuan, Hsiao, Po-Chien
• Format: Article
• Language: English
• Subjects: buckling-restrained brace; cumulative plastic deformation; ductility demand; Earth sciences; Earth, ocean, space; Earthquakes, seismology; energy dissipation; Engineering and environment geology. Geothermics; Engineering geology; Exact sciences and technology; gusset plate; Internal geophysics; rotational demand
• ISSN: 0098-8847; 1096-9845
• DOI: 10.1002/eqe.803

This paper is Part II of a two‐part paper describing a full‐scale 3‐story 3‐bay concrete‐filled tube (CFT)/buckling‐restrained braced frame (BRBF) specimen tested using psuedo‐dynamic testing procedures. The first paper described the specimen design, experiment, and simulation, whereas this paper focuses on the experimental responses of BRBs and BRB‐to‐gusset connections. This paper first evaluates the design of the gusset connections and the effects of the added edge stiffeners in improving the seismic performance of gusset connections. Test results suggest that an effective length factor of 2.0 should be considered for the design of the gusset plate without edge stiffeners. Tests also confirm that the cumulative plastic deformation (CPD) capacity of the BRBs adopted in the CFT/BRBF was lower than that found in typical component tests. The tests performed suggest that the reduction in the BRB CPD capacities observed in this full‐scale frame specimen could be due to the significant rotational demands imposed on the BRB‐to‐gusset joints. A simple method of computing such rotational demands from the frame inter‐story drift response demand is proposed. This paper also discusses other key experimental responses of the BRBs, such as effective stiffness, energy dissipation, and ductility demands. Copyright © 2008 John Wiley & Sons, Ltd.