This paper presents the formulation of an analytical model of buckling restrained
braces (BRBs) and its implementation into a structural optimization procedure in
order to design the protection system of an existing structure. The procedure, based
on a multi-performance approach, provides the minimum cost design solution,
through sizing and topology optimization of the BRBs, for the retrofit of an existing
structure. An analytical formulation for the BRBs is developed in order to introduce
an efficient characterization of these devices into the structural optimization
procedure. The prediction provided by the proposed analytical model is
compared with the results of an experimental test campaign and the bilinear
model.