Buckling Restrained Braced Frame with All-Bolted Gusset Connections

Abstract

A braced-frame, lateral-load-resisting system was developed in which inelastic deformations due to seismic loading were intended to be isolated to easily replaceable buckling restrained braces (BRB). Bolted brace-to-gusset and gusset-to—beam and column connections were utilized to facilitate simple brace and gusset plate installation and replacement. Full-scale testing using two BRBs was executed to assess performance. Analytical frame models were developed using the nonlinear load-deformation characteristics of the braces. The experimental and analytical results were compared to validate reasonable nonlinear parameters for industry use. All-bolted brace connections designed per AISC requirements provided adequate capacity to develop the BRBs. With proper detailing, inelastic deformations can be isolated substantially to the BRBs such that a repairable system is achieved. Load-deformation data for individual braces as provided by the supplier can be used to create reasonable analytical models for frames designed with all-bolted connections.