Applying the optimal integrated design methodology

This chapter deals with the proposed parametric analysis of the integrated design methodology by considering the set of acceleration records selected in the previous chapter. With reference to an equivalent SDOF integrated system, starting from the evaluation of the average displacement spectrum, combinations of the design variables, which are the lateral stiffness of the structural system, the static stiffness and the static damping coefficient of the viscoelastic dissipative bracing system, are evaluated for different values of the period of the system and of the seismic design displacement considered. Subsequently, the minimum of the cost index is searched for each group of cost ratios in order to find the optimal values of the design variables. This is followed by an economic comparison between the optimal integrated structural/control system and the optimal elastic braced structural system or the optimal elastic unbraced structural system without dampers for each target performance. In the last part, a validation of the proposed procedure is performed by verifying that an optimal single-degree-of-freedom integrated system achieves the expected seismic design displacement. Finally, the extension of this methodology to a proportionally damped multi-degrees-of-freedom framed integrated system is developed on the basis of specific hypotheses to demonstrate the effectiveness of the proposed integrated design methodology.