Title : SEISMIC PERFORMANCE OF STEEL FRAME STRUCTURES WITH HYBRID CONCENTRICALLY BRACE SYSTEMS
Authors : Muhamed S. Pandikkadavath and Dipti R. Sahoo
Publication : 13th – 16th February 2013
Volume :
Pages : 10-Jan
Price : 250
Abstract : This study investigates the possibility of a special hybrid bracing system for the seismic performance of steel framed structures in which conventional buckling-type brace and buckling-restrained brace (BRB) sections are connected in series to constitute a hybrid brace. The main objective is to dissipate the seismic energy through metallic yielding of the BRB element in both tension and compression without any incipient buckling. The conventional brace acts as the supporting element to the BRB element and increases the lateral stiffness of the frame to control the overall drift response. In this study, the effectiveness of this hybrid system is analytically investigated on a six-story steel frame with chevron braces using SAP 2000 software. Nonlinear characteristics of beams and columns are modelled using momentrotation plastic hinges, whereas those of BRBs are modelled using axial force-displacement plastic hinges at the mid-length. The seismic performance is evaluated through the extensive nonlinear time-history analysis using forty recorded ground motions representing the design basis earthquake and the maximum considered earthquake hazard levels. The main parameters investigated are: hinge mechanism, interstory drift response, lateral strength, and residual drift response. The performance of the hybrid system is also compared with that of concentrically braced frames and buckling-restrained braced frames.