Satisfying Inelastic Rotation Requirements for In-Plane Critical Axis Brace Buckling for High Seismic Design

William A. Thornton and Patrick J. Fortney (2012). "Satisfying Inelastic Rotation Requirements for In-Plane Critical Axis Brace Buckling for High Seismic Design," Engineering Journal, American Institute of Steel Construction, Vol. 49, pp. 99-108.

When a vertical brace buckles during a seismic event, its connections must be able to resist the available flexure strength of the brace about its critical buckling axis without fracture. This is achieved in most current practice by orienting the brace to buckle out-of-plane and introducing a hinge line in the gusset to permit large inelastic rotations with small out-of-plane flexure demand on the connections and the supporting members. In this paper, the authors introduce a connection configuration which allows the development of a hinge line which will permit large inelastic rotations for in-plane brace buckling with small flexural demand on the connection and supporting members. Keywords: bracing connections, gusset plate, buckling, seismic design, inelastic rotation.