Incorporating Frame Action into Seismic Design of Gusset Plates

Abstract

Gusset plates connect the brace and frame in concentrically braced frames (CBFs). Failure at the interface of gusset plates with the beam or column will result in an inability to achieve energy dissipation through brace buckling and yielding of the brace in tension and failure of the connection before the brace. Traditional design methods for the gusset plate beam or column interfaces in CBFs often consider only forces from brace action. Although studies have shown that forces from frame action can be significant, the complex stress distribution in the gusset plate makes it difficult to effectively evaluate their effects. Neglecting or inaccurately evaluating the frame action may result in unreasonable estimation of the forces in gusset plates, leading to failure at the interface connections. In this paper, the brace action and the frame action forces on gusset plates are systematically explored through an experimental test of CBFs. The proposed design method combines two models for brace action and frame action. Finally, the proposed design method is validated against results from CBF experiments. The proposed design method estimates the magnitude and orientation of the gusset plate interface forces with different configurations of CBFs well.