Alternative Approach to Light-Gage Beam Design

Local buckling of the compresison flanges reduces both the flexural stiffness and potential load carrying capacity of light gage beams, and must be taken into account in the design of such beams. Experimental and theoretical examinations of this problem are described for beams of lipped channel and trapezoidal sections. From the results of these examinations a straightforward direct method of obtaining the beam deflections for a given moment is formulated whereby the iterative procedure at present used in the AISI design manual is not required. Deflections calculated using this method are shown to agree well with experiments. A collapse criterion for these beams is compared with experimental collapse loads, showing good agreement. The extension of this analysis to suit light-gage beams in general is indicated.