عنوان مقاله [English]
Â Abstract Â Up to now many research projects have been conducted regarding vibration control of structures and reducing seismic demands of main structural members leading to better lateral performance. Passive metallic dampers as fuse elements has attracted many researchers according to their absorbing and damping capacity under severe cyclic loading condition. This lecture analytically investigates effect of adding rhombic metallic dampers on seismic performance of steel frames to be strengthened. Nonlinear time history analysis results of 5 story moment resisting frame showed (53% - 143%) increase in PGA amount that structure can resist and 40% reduction in roof displacement. Using dampers in bracing system in 7 story braced frame caused (54% - 175%) increase in PGA amount that structure can resist, increase in effective equivalent damping to 20% and 72% reduction in base shear. Using the damping strategy, seismic performance of both two type frames got improved from âcollapseâ level to âoperationalâ level.