Design of I-Shaped Columns with Diaphragm Bracing

A procedure is presented for the design of I-shaped columns braced by diaphragms. The diaphragms can be formed, e.g., by interconnected cold-formed steel panels which are often used as wall sheathing for steel framed buildings. The diaphragms may be directly attached to one or both flanges of the columns, or connected to girts which in turn are connected to the columns. The procedure is based on the ultimate load capacity of fully braced members, utilizing a conservative estimate of the shear strength and shear rigidity of the diaphragm. Design examples are included. In many instances the existing wall sheathing provides adequate bracing against buckling. The method is similar to one proposed earlier for diaphragm-braced I-section beams.