Optimal integrated seismic design of structural and viscoelastic bracing-damper systems

Passive structural control techniques are generally used as seismic rehabilitation and retrofit methodologies for existing structures. A poorly explored and exciting opportunity within structural seismic control research is represented by the possibility to design new structural forms and configurations, such as slender buildings, without compromising the structural performance through an integrated design approach. In this paper, with reference to viscous dampers, an integrated seismic design procedure of the elastic stiffness resources and viscoelastic properties of a dissipative bracing-damper system is proposed and developed to ensure a seismic design performance, within the displacement-based seismic design, explicitly taking into account the dynamic behaviour both of the structural and control systems. The optimal integrated seismic design is defined as the combination of the variables that minimizes a suitable index, representing an optimized objective function. Numerical examples of the proposed integrated cost-effectiveness seismic design approach both on an equivalent SDOF system and a proportionally damped MDOF integrated system are developed defining the design variables, which minimize the cost index. Validation of the effectiveness of the proposed integrated design procedure is carried out by evaluating the average displacement of the time-history responses to seven unscaled acceleration records selected according to EC8 provisions