Research on the Tensile Behavior of Stiffened Welded Hollow Spherical Joints Exposed to Fire

Abstract

Fire hazards are generally considered to be one of the major disasters that cause damage to grid structures, and when exposed to fire, their mechanical properties will directly affect whether the structure is safe. In this paper, the failure mode, strain analysis, load-displacement curve, initial axial stiffness, bearing capacity, and ductility of the joint are analyzed by the tensile testing of stiffened welded hollow spherical joints exposed to fire. The results show that the failure of the joint exposed to fire is a pull-out failure. With increasing temperature, the initial axial stiffness and bearing capacity of the joints gradually decrease. The ductility of joints exposed to fire shows an increasing trend with increasing temperature. The finite element model is verified based on the experimental results. Through parametric analysis, the calculation method for measuring the bearing capacity and initial axial stiffness of tensile-stiffened welded hollow spherical joints exposed to fire are proposed.