Reliability and adaptability of the analytical models proposed for the FRP systems to the Steel Reinforced Polymer and Steel Reinforced Grout strengthening systems

The paper presents a theoretical prediction of the structural behavior of reinforced concrete (RC) beams externally strengthened to flexure by using a unidirectional ultra-high tensile strength steel (UHTSS) reinforcing mesh embedded in an inorganic matrix (Steel Reinforced Grout, SRG) or in an organic matrix (Steel Reinforced Polymer, SRP).For these innovative composite materials are not yet available in literature specific standard documents, guidelines or analytical models capable to predict the structural behavior of the strengthened elements. Therefore, in order to evaluate the flexural strength of the strengthened beams some analytical models to predict the maximum axial strain developed in Fiber Reinforced Polymer (FRP) systems at the onset of intermediate debonding failure, have been used.The goal is to assess the effectiveness of current analytical models used, up to day, to FRP strengthening systems to the SRG and SRP strengthening systems. For this aim, a database of experimental results on RC beams strengthened in bending by bonded SRG and SRP systems has been collected.The comparisons between the theoretical predictions and the experimental data, in terms of debonding strain values, load carrying capacity, load-midspan deflection curves, have highlighted the reliability and adaptability of the current analytical models.Finally, in order to evaluate the effectiveness of the SRG and SRP systems for strengthening RC beams a parametric study was also carried out.