Building Resilience and Sustainability concrete structures with the use of FRP

The seismic retrofit topic is very debated nowadays, especially for those Countries that can count on a large number of existing, old and historical buildings. Many of these cannot be repaired or retrofitted through the most common systems (i.e. shear walls, base isolators, dampers…) due to architectural constraints and/or to budget limitations. Thus, the Fiber Reinforced Polymers (FRP) impose themselves as one of the best seismic retrofit system for existing buildings. The International Codes provide standards concerning the design of FRP wraps for a certain geometry and for a certain stress, but a set of rules for the placement on the structural elements is unknown. Therefore, this thesis aims to find the optimal layout of FRP-confined columns within a five story reinforced concrete frame, subjected to several nonlinear time history analysis. The inelastic numerical model has been realized using OpenSees. The optimization procedure is based on the minimization of the objective function C, defined as the square root of the sum of the squares of the interstory-drift ratios. With the aim of make more performing the procedure, the optimization research has been based on the Genetic Algorithms, that are biology-inspired methods used for global optimization, that seek the solution in the form of string of numbers, evolving at each iteration. The results have shown that there is a correlation more evident between the position of FRP-wrapped column and the minimization of C rather than the minimization of C and the number of FRP-wrapped columns. In particular the analysis have highlighted that is better to retrofit those columns where the maximum interstory drift ratio is expected.