Composite floor systems, consisting of reinforced concrete slabs and steel girders, are common in buildings and bridges. Partial restraints at the interface of the concrete slab and the steel girder have significant effects on the response of the composite beam. A few analytical models capable of accounting for these effects are available; however, none can be efficiently used for the nonlinear analysis of composite beams. In this paper, the basic governing equations are presented for a composite beam with deformable shear connectors under small displacements. Based on these equations, a new composite beam element is developed using the force method of analysis. The performance of this new element is compared with that of a previously developed displacement-based composite beam element. Both elements consist of two beam components connected through a deformable interface. A distributed spring model is used to account for the shear deformation at the interface. Two numerical examples on the nonlinear behavior of composite beams are solved using both displacement- and force-based elements. Comparison of the numerical results shows the superior performance of the newly developed force-based element over the displacement-based element.

Nonlinear Analysis of Composite Beams with Deformable Shear Connectors

A steel–concrete composite beam model with partial interaction including the shear deformability of the steel component

The non-linear analysis of composite steel–concrete beams by the finite elements method permits obtaining useful information on collapse modalities but the convergence of the solution must be carefully controlled. Using the displacement formulation of the finite elements technique, the authors illustrate some aspects related to the convergence of the method by comparing solutions deriving from finite elements with 8, 10 and 16DOF. Some pathologies of the 8DOF element are posed in evidence.

Non-linear analysis of composite beams of a displacement approach

Finite element models for nonlinear analysis of steel-concrete composite beams with partial interaction in combined bending and shear

This paper presents an advanced nonlinear finite-element (FE) program developed for the analysis of general composite structures of steel and reinforced concrete, including composite space trusses. The elements used to represent the concrete slab and steel beam actions are described, and in particular the ability to model ribbed composite slabs of reinforced concrete on profiled steel sheeting is demonstrated. Attention is drawn to the usefulness of the layering technique in determining local stress redistributions associated with progressive through-depth cracking and yielding in the slab and steel beam elements. Concrete is represented as a nonlinear elastic isotropic material before cracking and nonlinear orthotropic thereafter, while steel is taken to be initially elastic with strain-hardening capabilities after yielding. All material models are empirical in origin. A specialized stub element with empirical nonlinear shear force-slip relationships is used at the concrete slab–steel beam interface to p...

Hamada Sumio

Papers

Elastic-plastic analysis of composite beams with incomplete interaction by finite element method