Refractory Performance of the Axial Tensile Welded Hollow Spherical Joint

To study the refractory performance of the axial tensile welded hollow spherical joint, the steady-state test of heating under constant load was carried out on the joint specimens with different load levels. The failure modes, temperature field, displacement-time curves, and refractory performance of the spherical joints exposed to fire are investigated and analyzed. The experimental results indicate that the failure modes of the joints exposed to fire are pull-out failures. The failure location is at the intersection of the steel tube-hollow sphere. The lowest temperature is located at the intersection of the steel tube-hollow sphere. The closer you get to the equator of the hollow sphere, the higher the spherical temperature. The smaller the load level, the higher the refractory temperature and the longer the refractory limit of the joints. The correctness of the numerical model was verified by comparison with the experimental result. Numerical simulations show that with the increase of the load levels, the refractory performance of the joints gradually decreases, and the downward trend gradually slows down. Compared to the refractory temperature code-recommended, the refractory temperature of the tensile joints is very conservative.