Dissipative bracing solutions for sustainable seismic retrofit of RC structures

Dissipative bracing (DB) systems are among the most sustainable seismic retrofit strategies of reinforced concrete (RC) frame structures. Indeed, they allow to minimize the use of materials and the architectural impact, as well as emphasize the reversibility of the interventions and the reuse of the elements and components with which they are made. Research studies on DBbased seismic retrofit strategies usually focus on the application of single systems incorporating a specific type of damper. In order to offer a broader perspective on this class of technologies, a comparative study of two different DB systems is presented in this article. One system is equipped with Added Damping and Stiffness (ADAS) steel dissipators and the other one with Pressurized Fluid Viscous (PFV) spring-dampers. A representative case study is examined, i.e. a 6-storey building located in a medium-high seismicity zone in Italy, designed according to the 1986 edition of the National Seismic Standards. Expeditious criteria recently proposed by the authors are adopted to pre-size the two systems, applied for the first time here by including the infills in the time-history performance evaluation analyses. The article reports: the results of the seismic assessment study of the building; recalls on the presizing criteria of the two DB systems and the results of their application; a comparative analysis of the performance improvement of structural members and infills attained by the two retrofit solutions, with notes on possible different design choices of the ADAS and PFV dissipators; and evaluations on the cost and the architectural impact and sustainability of the two interventions.