The Static and Dynamic Behavior of Hybrid Steel Beams

The results of theoretical and experimental investigations on the behavior of hybrid beams subjected to static and fatigue loading are presented. The static loading investigations substantiated the use of simple plastic theory for hybrid beam analysis and illustrated that the bending behavior of hybrid beams does not differ significantly from the bending behavior of homogeneous (conventional) welded beams. Equations are suggested for computing the strength of hybrid beams in bending and combined shear and bending. The fatigue investigation, which included only a limited number of tests, was an exploratory investigation intended to provide preliminary information on the fatigue behavior of hybrid beams. Although the investigation could not therefore yield final conclusions, it did provide several preliminary conclusions and information that will be useful in planning a more extensive future program. Most important of these preliminary conclusions are: (1) the fatigue strength of the welded beams does not appear to be greatly affected by the web material for stress ratios of about zero, the hybrid beams being about as strong as the homogeneous beams; and (2) the fatigue data for the hybrid beams at a stress ratio of about zero is reasonably close to comparable data on fillet-welded axially loaded T-specimens of the flange material.