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Background: The seismic retrofitting of frame structures using hysteretic dampers is a very effective strategy to mitigate earthquake-induced risks. However, its application in current practice is rather limited since simple and efficient design methods are still lacking, and the more accurate time-history analysis is time-consuming and computationally demanding. Aims: This paper develops and applies a seismic retrofit design method to a complex real case study: An eight-story reinforced concrete residential building equipped with buckling-restrained braces. Methods: The design method permits the peak seismic response to be predicted, as well as the dampers to be added in the structure to obtain a uniform distribution of the ductility demand. For that purpose, a pushover analysis with the first mode load pattern is carried out. The corresponding story pushover curves are first idealized using a degrading trilinear model and then used to define the SDOF (Single Degree-of-Freedom) system equivalent to the RC frame. The SDOF system, equivalent to the damped braces, is designed to meet performance criteria based on a target drift angle. An optimal damper distribution rule is used to distribute the damped braces along the elevation to maximize the use of all dampers and obtain a uniform distribution of the ductility demand. Results: The effectiveness of the seismic retrofit is finally demonstrated by non-linear time-history analysis using a set of earthquake ground motions with various hazard levels. Conclusion: The results proved the design procedure is feasible and effective since it achieves the performance objectives of damage control in structural members and uniform ductility demand in dampers.

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Recent devastating earthquakes pointed out the high vulnerability of existing reinforced concrete (RC) buildings and the critical role of infills. The presence of stiff infills may significantly modify the lateral response of RC moment resisting frame buildings and cause severe damage on the surrounding RC members due to seismic actions transmitted at level of beamcolumn joints. Furthermore, due to their brittle response, they commonly exhibited severe damage often leading to high economic losses. In this context, effective seismic retrofit strategies should aim at both increasing the shear strength of RC members and reducing the damage to infills. However only few tests are available in literature addressing the seismic strengthening of existing RC frames accounting for the infill-to-structure interaction. To fill this gap a comprehensive experimental program of pseudo-dynamic tests on full-scale twostorey infilled RC frames has been designed and is currently ongoing at the full-scale laboratory testing of the University of Napoli Federico II. This paper reports the preliminary experimental results and numerical analyses carried out by using available non-linear models accounting for the infills contribution. The comparison between theoretical predictions and experimental results provides useful insights to improve the numerical models to reproduce the infill-to-strut interaction. Finally, a retrofit strategy to improve the seismic performance of the structural system and reducing the expected damage to infills is herein outlined.