Numerical analysis of RC beams strengthened with SRG

The use of Fiber Reinforced Polymer (FRP) strengthening systems for reinforced concrete (RC) members represents nowadays an effective alternative to traditional strengthening techniques. Recently, a new class of composites have emerged known as Steel Reinforced Grout (SRG), consisting of steel fibers embedded in an inorganic matrix and applied by using manual techniques and traditional handcraft. An experimental campaign was recently carried out that aims at assessing the performance and effectiveness of SRG strengthening systems to improve the flexural behavior of RC slabs. The present work uses the experimental results to validate the numerical prediction of a FEM code, developed by the authors, to analyze the flexural behavior of SRG-strengthened slabs. The cross-sectional response is obtained using a fiber-model equipped with a plasticity model for rebars, a continuum-damage model for SRG, and a plastic-damage model for concrete. Overall, the numerical predictions are in good agreement with the experimental results. The model reproduces with acceptable accuracy the nonlinear behavior of the tested strengthened beams, as well as the failure point both in terms of failure modes and ultimate strength and displacement. In some cases, slight differences can be found between the numerical and experimental results. These differences are discussed in this work.