GBT-based buckling analysis of composite steel-concrete beams

Resumo

Continuous restrained I-section beams may be subject to lateral-distortional buckling and web lateral
buckling in regions of negative bending. Buckling analysis of restrained beams demands time-consuming Shell
Finite Element Method (SFEM) models. SFEM is an important unquestionable tool to solve eigenvalue problems,
however, it requires models involving several degrees of freedom and substantial engineering judgment. This fact
explains why assessing the structural response of such structural systems constitutes a complex task. One very
promising route that has been explored in the last decade is the use of Generalized Beam Theory (GBT) − a beam
theory that incorporates genuine folded-plate concepts. In this context, a GBT-based analytical solution for the
distortional buckling is proposed. First, the continuous elastic torsional restraint is incorporated in the cross-section

distortional deformation mode. Next, a kinematic assumption comprising the null shear strain in each wall mid-
plane is imposed to determine the distortional displacement field. Finally, the buckling stress is derived from an

energy method. The accuracy of the solution is validated by numerical solutions provided by the 2.0 release of the
software GBTUL.