In order to explore the influence of panel zone sizes on the ultimate bearing capacity of H-shaped steel frames, this study examines a steel frame structure with cross-shaped sections consisting of beams, columns and panel zones based on mechanical equilibrium principles. The area ratio of either side of the flange to the web is taken as the main parameter.
The results show that the ultimate bearing capacity ratio curves can be grouped into three types. For the first type, the plastic hinge is formed in the panel zone. For the second type, when Rpcb, the strong column factor, is greater than 1.2, the plastic hinge is formed at the beam end; otherwise the plastic hinge is formed in the panel zone. For the third type, when Rpcb≤0.8, the plastic hinge is formed in the panel zone; otherwise the plastic hinge is formed at the beam end. The ultimate bearing capacity ratio curves of the local section of H-shaped steel largely fall in the first curve type, and the ultimate bearing capacity is larger when the panel zone size is excluded from the calculation than otherwise with the former being one to five times as large as the latter.