Effective Performance based Seismic Retrofit of Pre-code Reinforced Concrete Buildings

Seismic retrofit of reinforced concrete pre-code buildings is considered in this work. Nonlinear static pushover analysis is performed by means of specialized finite element software to obtain building response under the code prescribed seismic design load. Performance states that were considered include limitations of the total building roof displacement and of the maximum inter story drift. Three factors characterizing material, geometric and reinforcement of structural members were introduced. A full factorial design of experiment table had been used to define a finite set of data points where the base shears associated to drift displacements thresholds were evaluated. Response surface based models were derived then to write explicit expressions for the constraints related to the performance limit states. Optimization of seismic retrofit was finally carried out with the objective to minimize the total cost of retrofit operation