Experimental and Analytical Study of Asymmetric Structures with Different Viscous Damper Distribution

During the past decade, there were a lot of studies on the effect of energy dissipating devices such as dampers for controlling structural response in earthquake. Using a suitable distribution of these devices may have extra advantages by minimizing torsional effects in buildings. This investigation deals with a comparison study performed between the experimentally observed and numerically predicted dynamic behavior of a 1/6 scale structure with viscous dampers. The setup consists of a one-story model with one-way stiffness asymmetry which is connected to a rigid base structure by two viscous dampers. Both structures were located on the shaking table and the tests were conducted using 6 earthquake records. Several damper distributions have been considered and for each one, lateral displacement, lateral acceleration and diaphragm torsion of the model were recorded. The separate tests on dampers show that their dynamic properties are completely dependent on frequency and amplitude of the motion. The comparison between the experimental and numerical model shows an acceptable similarity in the response time histories. The results indicates that asymmetry effects on lateral displacement is minimized if the damping center is located at a distance equal to stiffness eccentricity in the opposite side of stiffness center with respect to the center of mass. Also, if the damping center is located near the center of mass on the flexible side with a high damping radius of gyration, diaphragm torsion is minimized. No suitable distribution was found for controlling lateral acceleration in this research.