Multi-objective loss-based optimization of viscous dampers for seismic retrofitting of irregular structures

In this paper an efficient first-order multi-objective optimization scheme is adopted for the design of linear viscous dampers for the seismic retrofitting of frame buildings. A retrofitting cost function serves as one objective while the expected losses serve as the other objective. These two objectives are well understood by decision makers that may not be engineers. Furthermore, with the Pareto front for these two objectives at hand, the decision maker can make his decisions with the whole picture at hand. To allow achieving the Pareto front with a reasonable computational effort, a first-order multi-objective optimization approach is adopted. The gradients of the expected loss function, required for the optimization, are analytically derived using the very efficient Adjoint Variable method. This considerably improves the computational efficiency of the methodology. The efficacy of the framework is illustrated with a 2D four storey frame and an eight-storey 3D asymmetric building.