Behavior of Hybrid Beams Subjected to Static Loads

Elastic and simple plastic theory are used to define the behavior of hybrid steel beams (beams with higher-strength steel flanges connected by lower-strength steel webs). Theoretical equations defining the moment-curvature relationship for pure bending and the initial yield and fully plastic conditions for combined bending and shear are presented. Tests on hybrid beams with different flange-yield strength to web-yield strength ratios show close agreement with the behavior predicted by the theoretical equations. Practical suggestions for hybrid beam design are presented. Comparable tests on conventional (homogeneous) welded beams demonstrate that the bending behavior of hybrid beams is not significantly different from that of conventional beams, especially when residual stresses are considered.