Equivalent flat plate models of composite floors

This paper studies the modelling of composite floors using equivalent orthotropic flat plate models. As a composite floor has a constant cross-section in one main direction and a periodically variable cross-section in the other main direction, the equivalent second moment of area of a profiled beam with periodically variable sections is first investigated. The stress transmission and distribution between two different and adjacent sections of the beam are examined and the effective section is then defined. The comparison of the maximum displacements and the fundamental natural frequencies of a profiled beam and its equivalent uniform beam show very good agreement under different loading and boundary conditions. Then the equivalence is applied to the modelling of a profiled plate and a profile plate with steel sheeting. A 3D solid model and its equivalent flat plate model of the profiled plates produce similar results. Finally the equivalent model is used to study the dynamic behaviour of a full-size composite floor in the steel framed Cardington Building. The measured while predicted natural frequencies and static stiffness are reasonably close and the analysis becomes simple and effective. © 2007 Civil-Comp Press.