SIMULTANEOUS STIFFNESS-DAMPING OPTIMIZATION OF STRUCTURES WITH RESPECT TO ACCELERATION, DISPLACEMENT AND BASE SHEAR

In this study the variation of the optimal stiffness and damping placement using a generalized objective function is presented that considers simultaneously displacements, absolute accelerations and base shear. The norm of the displacement, absolute acceleration and base shear transfer function is evaluated at the fundamental natural frequency of the system and its value is updated at every step of iteration. Its amplitude is minimized subject to a constraint of total stiffness and total damping. The optimization algorithm has been verified through numerical examples of a six-story building with soft story behavior, in a tall building with non-uniform stiffness and in a more practical planar frame. For every case study dynamic response analysis is performed using an ensemble of 25 accelerograms and results are shown in terms of mean of the peak maximum response and in the frequency domain.