The present thesis intended to contribute for the development of a new generation of highdurable and sustainable reinforced concrete (RC) beam structures submitted to flexuralloading, by combining the benefits that Glass Fiber Reinforced Polymers (GFRP) and steelbars can provide: the former due to their corrosion immunity, and the latter derived fromtheir high ductility. Furthermore, High Performance Fiber Reinforced Concrete (HPFRC)was developed to improve the ductility of such innovative structures. To avoid corrosion,steel bar was placed with a HPFRC cover thickness, higher than 100 mm, while GFRP barswere applied in the near tensile surface of the HPFRC beams. In addition, the GFRP andsteel bars were applied with a certain pre-stress level. The prestressing optimized theirreinforcing capabilities, and increased the service load carrying capacity of the beam. On theother hand, conventional shear reinforcements were not used, and they were totally replacedby HPFRC material. Due to the quite high post-cracking tensile strength and energyabsorption capacity that HPFRC attained, the composite system showed adequate shearresisting, and also enhancement in the structural performance at both Serviceability andUltimate Limit States (SLS and ULS). The work started with the assessment to bondbehavior between GFRP and HPFRC through experimental tests and analyticalinvestigation. The structural performance of this hybrid prestressed GFRP-steel reinforcedHPFRC was investigated by performing four-point bending tests on beams with I-shapedcross section under both monotonic and fatigue loading conditions. Moreover, an extensiveanalytical formulation was developed in order to theoretically address to the main structuralaspect of the tested beams. The obtained experimental results were captured well using therespective results from the analytical study. Finally, finite element (FE) simulations werecarried out using two well-known modelling approaches available in the literature forconcrete elements in form of both 2D and 3D models. The results obtained from these modelswere promising, a
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