Refined FEM Analysis of Steel-Concrete Composite Beam Subjected to Negative Bending and Axial Compressive Forces

This paper presents modelling techniques with finite element method (FEM) for a composite beam subjected to combined negative bending and axial compressive forces. Flexural behaviours of composite beam were thoroughly analysed to determine the ultimate limit state due to vertical and axial compressive forces. Failure state of composite beam was revealed by the level of axial compressive forces and reduced negative moment due to axial compressive forces. The results obtained from FEM analysis were compared with the results of experimental analysis. Reliability agreement has been observed between the results of FEM and experimental analysis on ultimate state behavior and failure modes. Detailed numerical techniques such as loading strategies in combined vertical and axial compressive directions and potential convergence problems due to complicated contacts between the material components are discussed in this paper. Finally simplified numerical techniques for uncertainties in axially compressed composite beam subjected to negative bending are suggested.