Numerical Modeling of Composite Castellated Beams

In modern composite structures, higher steel grades are used for structural steel profiles in order to increase span capacity without an unnecessary increase in the composite floor depth. This tendency results in beams that are more vulnerable to the failure modes that involve either web LSB (local shear buckling) and/or compression flange RDB (restrained distortional buckling). The effects of shear stresses as well as web buckling and post-buckling behavior on the overall beam performance have been investigated both experimentally and numerically in order to resolve the most important behavioral issues of plain-webbed composite beams. Less attention has been paid to investigations of instability effects on the ultimate strength of steel profiles in continuous castellated composite beam systems. In this paper, different finite element techniques are used to investigate the in-plane behavior with use of geometrically linear analysis and the out-of-plane distortional behavior with use of geometrically nonlinear analysis, with both techniques applied to trace the performance of continuous composite beams.