Study of the seismic performance of Centrically Fused Braced Frame (CFBF)

摘要

This paper presents an analytical study to investigate the seismic performance of Centrically Fused Braced Frame (CFBF) which was recently proposed. In CFBF systems, a very thin mid-height gusset plate with the specified details as a Structural Fuse (SF) is designed to dissipate the input energy demanded by seismic loading and tolerate large inelastic deformation while other structural element and connections including braces, beam, columns and corner gusset plates remain in elastic behavior range. This study describes summary results of four three-fourth scale experiments then a set of validated analytical Finite Element Models (FEMs) are developed based on latter experiments using displacement and damage evolution formulation to include the crack modeling explicitly. The results of this study confirms that the CBFB system is capable of concentrating the plastic strain demand at mid-height gusset as a central Structural Fuse (SF) efficiently for the studied bay width to story height ranging from 1.0 to 1.6 and specified details of mid-height gusset plate and the proposed detail for mid-height gusset plate as a Structural Fuse (SF) is able to provide the minimum requirements as desired by AISC codes for qualified Special Concentric Braced Frame (EBF). Finally, the proposed closed-form equation can predict the peak strength of proposed system having maximum error bounds less than 15%.