After a shear-type strongly braced steel frame suffers from non-sway buckling, the effective length factor for columns in a non-sway frame should be selected for stability calculations, and the P-δ effect should be considered for second-order analysis. However, an unreasonable design may result if the shear-type bracing cannot be accurately and practically designed to meet the strong bracing requirements. In this paper, an analytical method for the critical bracing design of shear-type strongly braced steel frames is proposed. First, the relationship between the shear-type bracing stiffness and buckling load of structures is analyzed, and then the calculation formula for the story critical bracing stiffness is derived based on the critical bracing stiffness of the separation column. Furthermore, the relationship between the cross-sectional properties of the shear-type brace members and the critical bracing lateral stiffness is established. Based on this, a direct calculation formula for the critical brace area of shear-type strongly braced steel frames is derived. This formula can determine whether a shear-type braced steel frame will experience sidesway or non-sway buckling, thereby providing a basis for selecting the appropriate approach for calculating the column effective length factor and second-order effects.
Lan et al. (Sat,) studied this question.