On simultaneous analysis and design optimization for seismic retrofitting with fluid viscous dampers

This brief note presents a novel approach to the optimization of fluid viscous dampers for seismic retrofitting applications. The size and placement of fluid viscous dampers is defined using a simultaneous analysis and design (SAND) optimization approach. The optimization variables are the damping coefficients of the dampers, and the structural response in time. In this way, the equations of motion become equality constraints of the optimization problem and are not solved directly with time-history analyses. A major advantage of SAND formulations is that special design sensitivity analysis methods are no longer needed to calculate the gradients of the objective and constraint functions. The possibility of selecting the damping coefficients of the dampers from a limited set of available sizes is also discussed.