Nonlinear finite element response sensitivity analysis of steel-concrete composite beams

The behavior of steel-concrete composite beams is strongly influenced by the type of connection between the steel beam and the concrete slab. For accurate analysis, the structural model must account properly for the interlayer slip between the components. This paper focuses on nonlinear finite element response sensitivity analysis using a displacement-based formulation for composite beams with deformable shear connection. Realistic uniaxial constitutive laws are adopted for the concrete and steel materials as well as for the shear connectors. A non-symmetrical two-span composite beam structure for which experimental results are available is used as application example. The finite element response is validated through the experimental results available for monotonic loading condition. Then, the finite element response sensitivity analysis is performed according to the Direct Differentiation Method (DDM) and validated through Forward Finite Difference (FFD) analysis. Selected results of the sensitivity analysis are presented in order to show the relative importance of concrete, steel, and shear connection material parameters.