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

Abstract

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. Integrated Seismic Design PhilosophyOver the past years, structure and control systems have been independently designed and, in some cases, optimized. Over the last 30 years, a lot of research has been developed on the integrated optimal design of structural/control systems.Specifically, the idea is to consider both the viscoelastic resources of the bracingdamper system as well as the elastic ones of the structural system from the beginning of design in order to obtain an integrated design of elastic structural/viscoelastic control systems. In this sense, the main variables that characterize the dynamic response of both systems are investigated as variables to be simultaneously optimized within the same design, the so-called ''integrated design''