Evaluation of the Simultaneous Application of Vertical and Horizontal Mass Isolation Techniques in the Moment Steel Frame Structures

In the recent decades, many efforts have been made to reduce the damages caused by strong earthquakes to the structural and non-structural systems of buildings utilizing various methods of seismic control of structures (active and passive). One of the most common passive seismic control systems is the horizontal isolation of buildings at their base level or base isolation. Another type of seismic isolation system, which is called vertical mass isolation and has been proposed in recent years, tries to separate the stiffness system and mass sub-system of the structures in some way.  In this research, the more efficient Simultaneous application of the horizontal base isolation together with the vertical mass isolation techniques, along with the use of a damping devices (such as viscous dampers), to improve the seismic performance of moment steel frame structures, has been investigated. For this purpose, the performance of the proposed hybrid system was evaluated by performing nonlinear time history dynamic analysis under the horizontal component of earthquake acceleration records. The results of the analysis obviously presented significant reductions in the maximum seismic responses of the studied structures especially for displacements, drifts and base shears compared to those responses of the other types of conventional structural systems with similar characteristics