Numerical analysis of the seismic performance of H-shaped steel joints with initial defects

The welding quality of beam-column joints of steel structures is one of the most important factors affecting seismic behavior of steel structures. In order to investigate the influence of initial defects on the seismic performance of H-shaped beam-column joints, the extended finite element method was used. A crack was set at the lower flange weld of H-shaped beam-column joints, and the influence of defect position and defect depth on the seismic performance was examined. The loading methods with different amplitudes were adopted. The research findings indicate that the initial defect exerts a significant influence on the seismic performance of the joint. The bearing capacity and energy dissipation capacity of the joints were decreased, and the degree of reduction accelerates with the increase of defect depth. However, the loading amplitude has a relatively minor effect on the seismic performance of the joint, with a maximum difference of 6.97% and an average difference of 0.31% in ultimate bending moment. Similarly, the influence of the initial defect location is limited, with a maximum difference of 11.9% and an average difference of 3.6%.