Stiffness characteristics of joints and influence on the stability of single-layer latticed domes

In this paper, the theoretical and practical formulas of initial stiffness of welded hollow spherical joints were presented, and the elastic and elastoplastic critical displacements and rotations were obtained respectively. A mechanical model considering the stiffness characteristics of joints was proposed, the criterion of eccentric states and bearing stages was established to analyse the influence on the stability of single-layer latticed domes. Results indicate that the practical initial stiffness formulas proposed fit well with the theoretical solutions. The mechanical model can accurately simulate the stiffness characteristics and bearing stages of joints in the failure process of structure. Compared with the experimental results, the average error of mechanical model for the initial slope of load-rotation curve is 8%, and the average error for the ultimate bearing capacity is 7%. The stiffness degeneration of the joints in the plastic stage may cause a significant reduction in stability capacity of the structure. The stability reduction factors of K6 and Geodesic domes are between 0.7 and 1.0, and the stability reduction factors of K8-lamella domes are between 0.65 and 1.0.