Numerical modeling of strengthened concrete beams

There are many cases where concrete structures need to be strengthened. Fiber reinforced polymer (FRP) composites, due to their high strength and corrosion resistance properties are widely applied in these cases.

This paper presents a non-linear finite element analysis of reinforced concrete beam strengthened with externally bonded FRP sheets under increasing flexural loads. The different materials models, for concrete, steel reinforcement and fibre reinforced polymers are taken into account. Elastic-plastic model with Drucker-Parger failure criterion and Rankine failure criterion are used to determine the yield surface and the fracture limit of respectively compressive and tensile concrete. Smeared model is used to represent the cracked concrete. Three-dimensional elements for concrete are used. The steel and FRP reinforcement carries only axial forces and considered as unidirectional materials. From the analysis, it is found that FEM can predict the load-displacement relation and good agreements were obtained when compared to the experimental data.