A method to simulate concrete structures (quasi-brittle material) with localized nonlinearities is presented. Based on Guyan’s condensation, it consists in replacing the elastic zones of the structure by their equivalent rigidities (super-elements). The nonlinear computation is then performed only on the zones of interest (ie, damaged). As new damaged zones may appear, the proposed method monitors the evolution of the system and re-integrates previously condensed areas if necessary. This method, applied on different tests cases, allows a substantial computation economy.