BENDING MECHANICAL PROPERTIES OF STEEL–WELDED HOLLOW SPHERICAL JOINTS AT HIGH TEMPERATURES

Spatial grid structure is a commonly used long–span structural form due to its various advantages, such as light weight, high strength, low construction cost, and simple construction. Steel–welded hollow spherical joints are widely applied in traditional spatial grid structures. Circular steel tube– and H–shaped steel–welded hollow spherical joints have been applied in practical engineering projects because of aesthetic appearance and structural stress requirements of modern spatial grid structures. Existing studies have mainly focused on the axial compression behaviors of steel–welded hollow spherical joints at high temperatures during fire disasters. However, few studies have discussed the bending mechanical properties of hollow and H–shaped steel–welded hollow spherical joints. This study conducted finite element analysis on the bending mechanical properties of circular steel tube– and H–shaped steel–welded hollow spherical joints at high temperatures. Influences of parameters including the sizes of welded hollow sphere and fashioned iron on the bending mechanical properties of welded hollow spherical joints were considered in the finite element analysis. Moreover, changes in the failure modes, flexural capacities, and flexural rigidities of circular steel tube– and H–shaped steel–welded hollow spherical joints with the increase in temperatures were analyzed. The fitting formulas of the ultimate bearing capacity and initial flexural rigidity of circular steel tube– and H–shaped steel–welded hollow spherical joints at high temperatures were proposed on the basis of parametric analysis.