Bending performance of connection-corroded welded hollow spherical joints

Indoor swimming pools are a typical aggressive environment in which long-span steel structures are prone to corrosion, especially in the connection position of joints. In order to evaluate the impact of the corrosion on the mechanical properties of joints, a corrosion test of Q235 steel in a swimming pool environment was carried out for 48 and 72 months respectively. The surface pitting distribution of the corrosion specimens was measured and statistically analyzed, and a probability distribution model of surface pit depth was established. Then, a finite element model of welded hollow spherical joint, which could simulate local corrosion and pit distribution, was established, and the parameter analysis of connection-corroded joints on bending performance was conducted. The results demonstrated that the hoop corrosion range and corrosion depth rate were the most sensitive parameters to the bending performance. Taking the number of hoop corrosion zones and corrosion depth rate as parameters, the bending bearing capacity degradation rates of connection-corroded joints based on a specific guarantee rate and different conditions were obtained. Finally, a convenient method for evaluating the joints' bending bearing capacity degradation rate was proposed, which could provide a reference for studying the mechanical properties of similar connection-corroded joints and evaluating the safety performance of grid structures.