The brace stiffness requirements for nodal bracing are inversely proportional to the unbraced length, Lb. Closer-spaced braces require more stiffness because the derivations are based upon allowing the column to reach a load that corresponds to buckling of the most critical unbraced length with a K-factor equal to 1.0. In many instances, there are more potential brace points than necessary to support the member forces required. Using the actual unbraced length may result in excessively conservative stiffness requirements. Therefore, the maximum unbraced length that enables the column to reach the required loading, Lq, can be used. For example, say the column shown in Figure 32.5 is supported against weak-axis buckling at three locations giving an unbraced length of L. If a single brace at midheight giving an unbraced length of 1.5L would be sufficient to carry the load on the column, then the required stiffness for the three braces could be conservatively estimated using the permissible unbraced length of 1.5L in Equation 32.10 in place of the actual unbraced length of L (see Example 32.3).

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