Rational retrofitting of existing rc frames combining member- and structure-level techniques

According to one of the possible classifications, seismic retrofitting interventions of existing structures can be grouped into two broad classes collecting the so-called member- and structure-level techniques. Under the conceptual standpoint, the former are primarily aimed at enhancing the capacity of single deficient members by means of various technical solutions, such as confinement, jacketing and so on, whereas the latter are intended at reducing seismic demand on the existing structure by means of new members or sub-structures, such as shear walls or steel bracings. The choice of the retrofitting technique generally depends on the level of the seismic vulnerability of the existing structure and on the building use and architecture. This paper outlines the concept of a rational strategy for the optimal combination of member- and structure-level techniques to achieve the optimal retrofitting solution. A parametric application will be proposed to point out the potential of such a strategy.