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Applied Structural Steel Design (4th Edition) by George F. Spiegel and George F. Limbrunner 9-2 Open Web Steel Joists, K-Series The design of the K-Series joist chord is based on a steel minimum yield strength of 50,000 psi. The design of the web members may be based on a steel minimum yield strength of 36,000 psi or 50,000 psi. An example of the standard designation for K-Series joists is 22K7. The depth of this joist is 22 in. K represents the series, and the number 7 denotes the relative size of the chords of the joist. Chord sizes are designated by the numbers 3 through 12, the size increasing with increasing number. The chord and web members may vary in shape and makeup from manufacturer to manufacturer, but the design and the capacity of the joists must conform to the SJI specifications and to the standardized load tables. The K-Series standard load table and the economy table (which is used for selection) are applicable where the joists are installed up to a maximum slope of 2 in. per foot. The use of open web steel joists in any given application must be based on SJI requirements as furnished in its standard specifications. These requirements for the K-Series joists are summarized as follows: In construction that uses joists, bridging and bridging anchors are required for the primary purpose of furnishing lateral stability for the joists, particularly during the construction phase. The bridging spans between and perpendicular to the steel joists. It is required that one end of all joists be attached to their supports before allowing the weight of an erector on the joists. When bolted connections are used, the bolts must be snug tightened. All bridging must be completely installed and the joists permanently fastened into place before the application of any construction loads. Even under the weight of an erector, the joists may exhibit some degree of lateral instability until the bridging is installed. The bridging also serves the purpose of holding t