LAUSR

Abstract Space frames are mostly steel structures whose material and mechanical properties are largely affected by the high temperature of fire such that the bearing capacity of the structure deteriorates. Welded hollow spherical joints, as the most widely used form of joints in space frames, are the key factors affecting structural stress. Thus, the resistance to fire of such joints must be further studied. In this paper, the mechanical properties of welded hollow spherical joints (abbreviated WHSJ) with H-beam under elevated temperature are investigated through experiment and finite element analysis. Axial compression tests at 300 °C, 500 °C, and 700 °C are used to analyze the failure modes of the joints under axial compression at high temperatures. The experiments obtained load–displacement curves, yield and ultimate bearing capacities, ductility, and initial axial stiffness. Furthermore, results are used to validate the finite element model. Through parametric analysis of temperature, steel grade, ribbed or non-ribbed, diameter, wall thickness, and H-beam section, the present study proposes formulas for designing joints with ultimate bearing capacity and initial axial stiffness to withstand high temperatures.