Diseño a cortante de vigas de hormigón armado con armadura de acero y armadura externa de FRP mediante el mecanismo de bielas y tirantes y algoritmos genéticos

Reinforced concrete beams strengthened with FRP. Shear design using the strut-and-tie mechanism and genetic algorithms

The use of composite materials to strengthen reinforced concrete structures has become increasingly popular in recent years. Three types of strengthening - bending, confinement and shear - have been addressed in the design guides published to date, although the third has been insufficiently developed. Further theoretical and experimental study is needed to obtain a fuller understanding of the mechanisms involved. In the theoretical study described in this paper, a strut and tie-based model was developed to determine the shear strength of reinforced concrete beams strengthened with fibre-reinforced polymer (FRP) bonded plates The contribution made by the concrete is reinforced by the effect of the tie, i.e., account is taken of the contributions of both the internal and external reinforcement, corresponding to the optimal strut-and-tie resisting mechanism. The optimal strength mechanism is found by solving an optimization problem with gene tic algorithms that define the optimal strut and tie geometry. The model proposed was validated by estimating the shear strength of experimentally tested FRP-strengthened beams. Model predictions were also compared to the predictions directly obtained by applying the methods set out in a number of concrete standards and design guides on FRP strengthening.