Investigating the effect of panel zone rigidity on behavior of tubular web reduced beam section connections

Concentrated major stresses in area of ​​beam-to-column welded connections of steel moment frames have been proposed in the high density demands as a critical factor in connection vulnerabilities. Reducing the stress concentration in the connections can be accomplished with the intentionally weakening of the cross section of the beam connected to the column. By this method, the plastic hing is formed in the weakened section and the demand is included on the connecting components. In this study, the effect of the panel rigidity on the behavior of the beam connection with the reduced bending strength section with the tube has been investigated. Eight connections of various thicknesses have been investigated. Connections are analyzed using finite element modeling under static loading. In this research, it is observed that with increasing the thickness of the web panel zone, the loss of the strength curve decreases and the connection experiences more drift. Also by increasing the thickness the von mises stress in the panel zone decreased. The values ​​of stress and displacement were observed in the tube web in larger thicknesses are bigger. The failure of the column and the connection panel zone in the connections decreased with the increase of the connection panel zone thickness. The lowest energy dissipation is related to the weakest panel zone connection. By increasing the thickness of the panel zone connection, it would be expected that more energy would be lost from the connection. In general, according to the results obtained in this study, application of thickness less than the calculated value in seismic design is not recommended.