Numerical Study on the Strength of Pipe Joints

With respect to the collapse behavior of joints in a steel pipe truss structure, in the present study, we carry out numerical analyses using a general-purpose FEM software package on the yield strength and the stress distribution near the connection in order to obtain information on the collapse behavior and the yield strength of joints. -joint and -joint are investigated. It is found that the joint strength is proportional to the th power of thickness of a main tube for various joints with a fixed branch-to-chord diameter ratio /. The index changes with / and in the range of /=0.1 to 0.91, ≅1.93 to 1.55 holds with smaller values corresponding to larger /. A compressive axial force along the main tube will reduce the joint strength, and it is also found that the strength-reduction ratio for -joint is almost the same as that for -joint having the same and /. Also, the joint strength is influenced by the span length of the main tube. The joint strength decreases as the span length increases. However, the influence is small for small /.