Composite beam-columns with interlayer slip - exact analysis

Exact first- and second-order analyses for composite beam-columns with partial interaction and subjected to transverse and axial loading are presented. General closed-form solutions for the displacement functions and the various actions in the composite element are presented for the first- and second-order cases. In this paper, the axial loads acting on the composite elements are assumed to be proportioned in accordance with their relative axial stiffnesses so that their resultant acts at the centroid of the transformed cross-sectional area of the fully composite member. Resultant axial loads active at the centroid ensure that, in the first-order analysis, the composite elements are subjected to uniform axial strain through the depth of the member and that no bending is induced by the resultant axial load. The analysis procedures are applied to simply supported beam-columns subjected to an axial force and a uniformly distributed transverse load to obtain closed-form solutions for the internal actions and displacements. The difference in the first- and second-order analysis approaches is illustrated by applying the solutions to a given beam-column problem.