FE modeling of RC beams externally strengthened with innovative materials

• An experimental study on a set of RC beams strengthened with a SRG system is shown.
• The tested beams were modeled by using a three-dimensional FE model.
• A delamination damage model for the interface concrete-SRG system was used.
• The performance and ductility of the strengthened beams were analyzed.
• A parametric study on similar beams was developed.

The paper presents the results obtained from a finite element analysis compared with those of an experimental investigation carried out on a set of reinforced concrete beams externally strengthened to flexure. An innovative steel reinforced grout system with two different external reinforcement (with and without end anchorages) was used to evaluate the effectiveness of the strengthening system.A multi-crack concrete model and a delamination damage model for the interface between concrete and external reinforcement were adopted.All the beams were extensively instrumented and tested under four-point bending. Loads at concrete cracking, yielding of tension steel and at ultimate, as well as, strains in compression concrete, tension steel and external reinforcement, were detected and compared with the numerical results. The performance of the strengthened beams, in terms of load–deflection curves, strength and ductility, was also evaluated and compared with those of the control beam to highlight the main parameters which affect the mode of failure and the overall behavior of the structural elements.Finally, in order to study the structural behavior of different types of strengthened beams a parametric analysis has been developed.