Advanced analysis of members with gusset plate joints

Abstract

The compressive resistance of truss members connected by gusset plates is estimated by taking the buckling length of the member equal to the member length. Usually, no check is provided for the gusset plate, although several design methods were proposed in the past. The paper presents an advanced member analysis, a design-oriented finite element method of a member including its joints. Geometrically and materially nonlinear analysis with imperfections is used to determine the load resistance of the joint-member-joint subsystem. Component-based Finite Element Method is used for joints; i.e. bolts and welds are modeled by nonlinear springs with properties based on design codes. The advanced analysis is demonstrated on two cases. The buckling length of angles, vastly used for masts, may be assumed smaller than the theoretical length if the boundary conditions determined by bolted gusset plates provide sufficient stiffness. The experiments and detailed numerical analysis performed at the Graz University of Technology are used for validation of the advanced analysis. The buckling resistance of gusset plates may govern the compressive resistance of the bracing. The experiments performed at the Czech Technical University in Prague (Vesecký), together with analytical design methods, are used for validation of buckling resistance of bolted eccentric gusset plate joints of circular hollow section braces. The results depend on the chosen shape and amplitude of initial imperfections. Using recommended procedures, the proposed method provides results very close to the experiments.