Nonlinear analysis of thin-walled spatial steel structures

Based on the space beam element analytical model, a thin-walled beam element model considering the restrained torsion was derived. The elastic stiffness matrix of this model is 14 × 14. The effects of axial force, shearing force, biaxial bending moment and bimoment were involved in the geometrical stiffness matrix of element. The yielding developments both across the section and along the axis of the member were taken into consideration by the finite-cut of element, and the elasto-plastic analysis of thin-walled spatial steel structures was achieved. Numerical examples prove the correctness of the analysis model, and show the characteristics of warping restraint torsion of thin-walled spatial structures.