Stability of Buckling-Restrained Brace (BRB) System Using a Simplified Direct Analysis Method

Abstract

Developed by Japanese researchers in the late 1980’s, and first implemented in New Zealand in the early 1990’s, Buckling-Restrained Braced Frame (BRBF) systems have achieved significant popularity in New Zealand, especially following the 2010/2011 Canterbury earthquakes. BRBFs can be designed to be very ductile and, as such, they are potentially capable of absorbing significant hysteretic energy during the large inelastic excursions that are expected in a major earthquake event. For these reasons, they have recently garnered the attention of many researchers and structural engineers. Nevertheless, the stability of the BRB connections that are designed in accordance with current conventions have been problematic, and this has led to the premature failure of these systems during some recent experimental tests. To avoid the instability of this lateral load resisting system, the present study has set out to investigate an innovative design method that incorporates the key parameters of the BRB members and gusset plate connections into ensuring the stability of the overall bracing system. The proposed design procedure has been verified with reference to large-scale experimental tests and provides a dependable practice in that regard for the stability analysis and design of the BRBF system, comprising the brace, gusset plate connection, and the frame into which the brace is attached.