Seismic response mitigation of atrium buildings with truss-IMD system

In this paper, a novel truss-inertial mass damper (IMD) system is developed for seismic response mitigation of atrium buildings with an internal structure. An IMD with nonlinear damping characteristic is introduced to provide passive vibration control, and the unsynchronized dynamic response between the tops of the building and the structure inside the atrium is utilized to activate the IMD for energy dissipation purpose. Parametric studies are conducted to evaluate the effectiveness of the truss-IMD system on suppressing structural responses under earthquakes, with two performance indices set to reflect the response intensities in interstory drift and story absolute acceleration. Results indicate that for a preset IMD nonlinearity, there exists an optimal combination of inertance and damping coefficient to maximize a building performance for a given equivalent stiffness of the truss and internal structure. Results also show that the maximum achievable structural performance and the corresponding optimal IMD design parameters generally increase with increasing effective stiffness for a given velocity exponent. Multi-objective optimizations are also performed to further evaluate the capacity of the proposed system in reducing the interstory drift and story acceleration simultaneously using a 6-story building.