6.1general provisions

Bracing systems shall have the strength and stiffness specified in this appendix, as applicable. Where such a system braces more than one member, the strength and stiffness of the bracing shall be based on the sum of the required strengths of all members being braced, and shall consider the flexibility of all components in the system. The evaluation of the stiffness furnished by the bracing shall include the effects of connections and anchoring details.

User Note: More detailed analyses for bracing strength and stiffness are presented in the Commentary.

A panel brace (formerly referred to as a relative brace) limits the angular deviation of a segment of the braced member between braced points (that is, the lateral displacement of one end of the segment relative to the other). A point brace (formerly referred to as a nodal brace) limits the movement at the braced point without direct interaction with adjacent braced points. A continuous bracing system consists of bracing that is attached along the entire member length.

The available strength and stiffness of the bracing members and connections shall equal or exceed the required strength and stiffness, respectively, unless analysis indicates that smaller values are justified.

Columns, beams, and beam-columns with end and intermediate braced points designed to meet the requirements in Sections 6.2, 6.3, and 6.4, as applicable, are permitted to be designed based on lengths $L_{c}$ and $L_{b}$, as defined in Chapters E and F, taken equal to the distance between the braced points.

In lieu of the requirements of Sections 6.2, 6.3, and 6.4,

• (a) The required brace strength and stiffness can be obtained using a second-order analysis that satisfies the provisions of Chapter C or Appendix 1, as appropriate, and includes brace points displaced from their nominal locations in a pattern that provides for the greatest demand on the bracing.
• (b) The required bracing stiffness can be obtained as $2 / \phi$ (LRFD) or $2 \Omega$ (ASD) times the ideal bracing stiffness determined from a buckling analysis. The required brace strength can be determined using the provisions of Sections 6.2, 6.3, and 6.4, as applicable.
• (c) For either of the above analysis methods, members with end or intermediate braced points meeting these requirements may be designed based on effective lengths, $L_{c}$ and $L_{b}$, taken less than the distance between braced points.

User Note: The stability bracing requirements in Sections 6.2, 6.3, and 6.4 are based on buckling analysis models involving idealizations of common bracing conditions. Computational analysis methods may be used for greater generality, accuracy, and efficiency for more complex bracing conditions. The Commentary to Section 6.1 provides guidance on these considerations.