Optimum proportions for hybrid girders
Holt, Edward C.
Master of Science
An analytical investigation is made to find optimum proportions for hybrid girders. These optimum proportions must satisfy the bending and shearing requirements and the cost will be the minimum, compared to other possible girder proportions. The girders considered here are laterally supported and without intermediate web stiffeners. Using the working stress provisions of the AISC specifications as the design criteria, formulas are derived. The procedure to obtain optimum cross section is straightforward. Examples are given to illustrate the use of these formulas. It Is shown that optimum cross sections are generally deeper than conventional sections. One may use this optimum web depth as a guide to select a suitable shallower web depth. This information will assist engineers in designing girders.