Design of Unstiffened Girders

Abstract

This paper deals with the design of girders without intermediate stiffeners, on the basis of the current 1963 AISC Specification, Part 1 (Working Stress Method). A typical unstiffened girder is shown in section in Fig. 1. The notation used is shown in this figure and Appendix A. The usual problem in design is to size the girder for a given moment M and shear V. The usual procedure is to try several girder depths, to perform a preliminary design for each depth, to compute the sectional area resulting from each preliminary design, and then to select one of the designs, frequently the one that gives the least area. Table 1 has been developed with the object of guiding and facilitating the designers task. It gives in compact form expressions for the sectional area of unstiffened girders and for some other quantities useful in design. The effect on girder weight of changing the overall depth and the grade of steel are clearly apparent in these expressions.