Design and analysis of concentrically braced steel frames under seismic loading

Abstract

The lateral resistance of many steel framed structures is provided by diagonal brace members and their connections to the frame. Although concentrically braced frames (CBFs) are common throughout international design guidance, their behaviour is still not fully understood. Conventional seismic design of gusset plate cormections utilises a clearance zone that permits outof- plane brace deformation but results in large and stiff gusset plates that do not buckle or yield along the axis of the brace member. Recent design proposals suggest using an elliptical clearance zone and reducing all gusset plate dimensions to permit yielding in the gusset plate after brace buckling and yielding. This strength hierarchy can result in improved brace member and global frame ductility.