NSGA-II based multi-objective optimization in design of Pall friction dampers

•Genetic algorithm is applied for the design of Pall dampers in building frames.•Uniform and optimal height-wise distributions of slip load are investigated.•Uniform and optimal height-wise distributions of dampers are investigated.•By applying a multi-objective optimization, the design cost can be reduced.

In the first part of this paper, it is aimed to investigate the optimal slip loads of Pall friction dampers of building frame either the dampers of all stories have the same slip loads or each damper has its own slip load. In both cases the total slip loads are assumed the same. Three objectives are simultaneously satisfied in the optimization procedure based on the fast and elitist non-dominated sorting genetic algorithm (NSGA-II). In the second part of this study, in seeking to achieve a cost effective design, a multi-objective optimization procedure is applied for finding the optimal placement of Pall dampers with assumed properties which satisfies the desired multi-objectives. For numerical studies, a 10-story shear braced frame under an ensemble of 10 earthquake records is used. The seismic responses of the designed controlled frames and uncontrolled frames are compared and the effectiveness of the above optimal designs is evaluated.