Optimal control based on damage of concrete moment-resisting frames retrofitted with nonlinear viscous dampers

This research introduces a methodology for designing viscous dampers with a primary focus on seismic damage as a vital measure of structural response. Utilizing the Park-Ang damage index, the level of damage is determined by integrating the damage related to the deformation of the elements and the dissipation of hysteretic energy made by the structural elements. The approach taken involves framing the design problem within the context of an optimization framework. The aim is to minimize the actual cost of retrofitting functions, concurrently adhering to the constraints imposed by the Park-Ang damage index and considering a chosen set of earthquake records. The cost function encompasses the dampers' expenses. The nonlinear viscous damper arrangement in the building's height has been determined so that the resulting structure incurs the minimum retrofitting cost. This approach is demonstrated by achieving an optimal design for viscous dampers in an 8-story concrete moment-resisting frame (CMRF) that is non-elastic and resistant to bending. Utilizing particle swarm optimization approaches to identify the optimal design, the results reveal that the optimized viscous dampers significantly reduce structural component damages and enhance the seismic fragility of the CMRF at various damage levels.