Studies on fracture behavior of beam-to-column web connections with tapered beam flange plates in steel moment frames

To quantify the variation of stress intensity factor to weld root flaw sizes in beam-to-column web connections, a methods that combines fracture mechanics and finite element analysis is presented. Fracture toughness demands were evaluated in terms of the Mode I stress intensity factor. The stress intensity factor was calculated through J-integral approach. The connection geometry was separately investigated in terms of the beam and column properties. The influences of the length of beam, column and beam flange plate on the stress intensity factor were analyzed. The fracture toughness demands were studied for the flaw on the top of the beam flange and the bottom surface, respectively. Finally, formulas for stress intensity factor were derived by orthogonal design. Results show that the deformation of panel zone has significant effects on stress intensity factor. The likelihood of top flange fractures is smaller than that of bottom flange fracture. Stress intensity factor increases with the increase of beam parameters and is reduced with the increase of column parameters.