| This research presents a three dimensional Finite Element modelling (FE) and parametric studies of steel-concrete composite beams strengthened in flexure with prestressed and non-prestressed Externally Bonded (EB) Fibre Reinforced Polymer (FRP) plates and sheets. Two types of FRP materials are considered, consisting of Carbon Fibre Reinforced Polymer (CFRP) and Steel Fibre Reinforced Polymer (SFRP). The experimental results of one non-prestressed and seven prestressed large-scale steel-concrete composite beam specimens were used to validate the FE model. The main challenge was to numerically model the prestressing force. The models were developed using the ANSYS FE software. Comparisons were carried out in terms of load-deflection behaviour, strain profile along the length of the beams and strain distribution across the depth at the mid-span section. Promising agreements were observed between the FE and the experimental results. Furthermore, parametric studies were done to investigate the behaviour of this strengthening system using the validated numerical and analytical models. The effects of prestress level on the behaviour of the system was investigated and based on the ductility of the beams, an optimal prestress level was introduced. Moreover, the effects of axial stiffness of the strengthening material, steel yield strength and concrete compressive strength were investigated and design philosophies and guidelines were presented. |
