In the following calculation procedures, the design of steel members is executed in accordance with the Specification for the Design, Fabrication and Erection of Structural Steel for Buildings of the American Institute of Steel Construction. This specification is presented in the AISC Manual of Steel Construction. Most allowable stresses are functions of the yield-point stress, denoted as Fy in the Manual. The appendix of the Specification presents the allowable stresses associated with each grade of structural steel together with tables intended to expedite the design. The Commentary in the Specification explains the structural theory underlying the Specification