5. Integrated Design of Proportionally Damped Framed Structural Systems Equipped with Viscous Devices

This chapter deals with the integrated design of the elastic structural system and the viscoelastic dissipative bracing system to achieve an expected seismic design displacement. The variables that characterize the design problem, their domain and the steps of the proposed methodology are illustrated and commented in details by taking into account the concepts described in the previous chapters. A set of seven historical unscaled acceleration records is selected to develop dynamic analyses by testing the proposed integrated design methodology. With reference to an equivalent SDOF integrated system, a cost index, assumed as an optimized objective function and defined on the design variables, is described in order to find the optimal design in economic terms, or rather, the economically optimal combination of the design variables for each expected seismic target performance. Finally, the extension of the results, developed on the substitute structure, to a viscoelastically and proportionally damped MDOF framed integrated system is explained in order to design the least expensive regular system.