Direct performance-based design with 200 kN MR dampers using multi-objective cost effective optimization for steel MRFs

• A direct performance-based design (PBD) methodology is proposed by incorporating PBD and semi-active damper.
• Multi-objective genetic algorithms are used to find optimal control device layout to satisfy performance levels.
• One objective design earthquake is used to PBD for multiple performance levels subjected to multiple hazard levels.
• The direct performance-based control design approach can achieve the desired performance levels.

Direct performance-based design methodology that incorporates traditional performance-based design and semi-active smart damping devices (i.e., magnetorheological (MR) damper) has been investigated through the application of multi-objective optimization. This design method achieves multiple objectives in which cost and efficiency are simultaneously optimized to achieve multiple performance levels subjected to multiple hazard levels. For numerical study, large-scale 200 kN MR dampers have been installed in a 9-story moment-resisting frame building to carry out multi-objective optimization using genetic algorithm. Minimum interstory drift during through nonlinear time history analysis and minimum number of MR dampers installed are considered as performance-based design objectives. Several MR damper location layouts have been obtained through the optimization. Nonlinear time history analyses have been carried out to evaluate performance of each MR damper device layout.