Building structures may encounter strong wind, earthquake, snowstorm, and other disaster loads during their service period. Therefore, the members and joints may incur different degrees of damages. However, some damaged members and joints can continue functioning after reasonable assessment and repair. In this study, drum-welded hollow spherical joints (DWHSJs) that are used in Beijing’s New International Airport were considered as research objects. Experimental and numerical analyses were conducted to investigate the compressive bearing capacity of the DWHSJs and their degradation when they suffered damage. Then, using parametric analysis, the effect of various factors on the degradation of the bearing capacity of damaged joints was revealed. Finally, according to the experimental and numerical analysis results, a practical formula for calculating the bearing capacity of damaged joints under axial compression was proposed. A reduction factor of the bearing capacity based on the residual deformation of joints was introduced in the formula. A comparison showed that the calculation results were relatively consistent with the experimental results.