Buckling analysis of gusset plates with bolted connections using finite element modeling

Abstract

Gusset plates connect lateral bracing to a building by fixing two perpendicular edges into the corners of a frame. This means that along the length of a gusset plate the cross sectional area is not uniform. For these reasons, stress distribution through a gusset plate is complex and difficult to predict. This has motivated design methods based upon approximate yield force analysis for gusset plates. The Whitmore width method (1952) is a widely adopted method used to size the yielding area of gusset plates in tension or those that do not buckle in compression. When considering buckling, international design codes prescribe equations that calculate strength curves that reduce the yielding capacity based on slenderness. However, these design code methods are based on column buckling behavior and are not specific to gusset plates. This study uses finite element modeling to study the development of yielding and buckling behavior in gusset plates with bolted connections. In total 184 variations of gusset plate geometries were modelled in Abaqus®. The simulated testing assumed an initial imperfection and applied a monotonic uniaxial load. Upon comparing results to current design methods, it was found that the Whitmore width is generally un-conservative in predicting initial yielding of gusset plates. By using the Thornton method with modifications based on FEA observations of gusset plate behavior, a new yield area and compressive strength curve suitable for gusset plates is proposed. These changes improved accuracy and safety in the design of gusset plates without adding complexity to the design process.