Mechanical behavior research on multi-planar steel tubular joints with inner plate

Atypical multi-planar steel tubular joints with inner plate can be used in complicated spatial truss structures for design flexibility. Full-scale test and finite element model analysis on a multi-planar steel tubular joint with inner plate under axial compression of main braces and chord were carried out to study the development of the deformation and stress of the joint. The failure pattern of the joint was the local buckling failure of the compressed brace at joint. The research indicates that under the load of 1.3 times the design the joint keeps in elastic state, has a high degree of safety, and meets the design requirement. The numerical analysis can simulate the loading test perfectively, and effectively meet the shortfall of the insufficient measuring points of joint tests. Additionally, the smaller ratio of diameter to thickness of the chord and stiffened plates in the chord can enhance the radial stiffness of the chord, and ensure the chord to be in elastic state at the joint failure. The stiffened plate in the main braces has little influence on the elastic stiffness and bearing capacity of the braces, but can restrain the radical deformation of the braces and improve their stress distribution states. The structure design of the joint is reasonable, and the joint is safe under design loads.