Service and ultimate analyses of composite beams with partial interaction in combined bending and shear

This paper compares three different beam models for the linear viscoelastic (service state) analysis and nonlinear (ultimate state) analysis of composite members with partial interaction. These models are derived by coupling with a deformable shear connection two Euler-Bernoulli beams (only flexural deformability and flexural failure mode), an Euler-Bernoulli beam to a Timoshenko beam (addition of shear deformability and shear failure mode for one component only), and two Timoshenko beams (addition of shear deformability and shear failure mode for both components). Results of service state analyses involving 200 realistic simply supported and three-span composite beams as well as results of nonlinear analyses involving experimentally tested simply supported and continuous beams are illustrated in order to study the effects of shear in the steel and slab components at various load levels. Results show that the three models show small differences when composite beams are dominated by the bending behaviour. Conversely, differences are significant for beams in which the interaction between bending and shear plays a substantial role.