Semi-Active Control of 3D- Vertically Isolated Buildings with Divided Skeleton into Inner and Outer Subsystems with MR- Dampers

In vertical isolation, the lateral load resisting system is divided into two substructures which are stiff with less system mass and flexible with more system mass. As the system experiences an earthquake, vertical isolation benefits from the prominent difference between the periods of the two sub-systems and the damping mechanisms placed between them across the height. Though effective passive isolation techniques are still susceptible to seismic source characteristics. In this study, the semi-active controlled strategy by using the magnetorheological dampers was investigated in a 3D state in 6, 9, and 12- story buildings, with skeletons divided into two inner and outer sub-systems as stiff and flexible parts. The lumped mass 3D models of the buildings are introduced to MATLAB and subjected to 7 bidirectional ground motions. The analysis results showed that the passive control of viscous dampers is only effective in harnessing the stiff sub-system response to nearly half of the uncontrolled building. However, in the soft sub-system, the inter-story drift on average is 16 percent greater than the uncontrolled building. The semi-active control, however, at the stiff sub-system has a maximum roof displacement, acceleration, and inter-story rotation nearly to 10, 40, and 14 percent of the uncontrolled ones. In addition, the average response for the soft sub-system remained less than half.