OTTIMIZZAZIONE STRUTTURALE NELLA PROGETTAZIONE DI UN NUOVO EDIFICIO MEDIANTE L'USO DI CONTROVENTI DISSIPATIVI TIPO “BRAD”

The development of precast technology for reinforced and pre-stressed reinforced concrete, brought in the last few years an increasing diffusion of precast system in buildings. This kind of structural systems, used at the beginning for industrial buildings and warehouse are nowadays spreading even for other accomodation with increasing strucural irregularity and complex geometry. This fact, in the light of the Italian buildings code, that recommends structural regularity, causes important effect also in mid-low risk seismic zone because of torsional effects issue coming from irregularity. Moreover, precast structures bearing from isostatic columns both single and multi-storey, show displacements under horizontal loads, often bigger than maximum admitted for serviceability limit states. This paper, presents the results of a study having the scope to compare two different design approach: the former is a classical approach, the latter instead utilizes Buckling-Restrained Axial Dampers (BRAD). They are particularly suitablet to be insert like dissipative bracings especially in precast reinforced concrete because they reduce both absolute and inter-storey drifts. The case study of this paper are three different buildings: a regular plan two-storey structure, a irregular plan two-storey structure and a three-story structure. By means of the obtained results, it is showed how with the use of BRAD is possible to regularize the dynamic behaviour of structures, limiting at the same time the inter-storey drifts and reaching high standards of structural optimization increasing.