| Directly welded intersecting joints have been enjoyed by more and more engineers for their lively lines and beautiful outline. Some of these joints, e.g. gap joints withβ<0.8, mostly produce sags and crests on the face of the chord, which embodies the flexibility of the joints. The effect of joint stiffness on the static and dynamic behavior of the spatial triangular trusses is analyzed by the finite element analysis method. Here are the main parts of the analytic work:(1) According to existing codes and research findings, spatial triangular SHS truss and the support of the truss are designed. On account of the differences between the spatial and planar trusses and the lack of the specification about the spatial SHS joints in existing codes, a reduction method to planar joints is adopted for spatial joint design and two attentions about the design of the spatial triangular truss are brought forward in this article.(2) The whole truss model is established by the ANSYS software with SHELL43 element and calculated by considering the material and geometrical nonlinear under dead load. And the feasibility of the half-span model of the truss is verified. In succession, the static behavior of the truss is analyzed by the comparison with the existing truss analysis models, including the distribution of the member forces, the whole deformation, the plastoelastic deformation of joints, the redistribution of member forces and the analysis of the limit state.(3) By a group of the trusses having different joint stiffness, the effect of the joint stiffness on truss static behavior is analyzed. A simplified model considering the joint axial rigidity is proposed and its feasibility and accuracy is verified. At the same time, a suggestion that may popularize the simplified model is put forward and briefly verified.(4) The dynamic behavior of a spatial triangular SHS truss is preliminarily explored by the modal analysis and the dynamic time-history analysis.
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