Seismic Vibration Control of Moment-Resistant Concrete Frames Using Nonlinear Viscous Dampers

This study aims to investigate the performance of nonlinear viscous damper (NVD) in seismic vibration control of reinforced concrete moment-resisting frames. To this aim, five RC moment frames (1-, 2-, 4-, 8-, and 12-stories) with and without NVD were examined. To evaluate the seismic behavior of the models, different records were considered, including high period (HP), low period (LP), near field (NF), far field (FF), low dominant high mean period (LDHM), and the ground motions that carry directivity effects (D). The effects of height and frequency of reinforced concrete frames were studied. The simulations and analyses were conducted using nonlinear dynamic time-history analysis in SAP 2000. According to the results, by increasing the exponential coefficient of the damper (alpha) from 0.15 to 0.50, the damping performance is optimally improved under the effect of more ground motions. Nonlinear viscous dampers under high period (HP), and near-fault (NP) ground motions, especially ground motions that carry directivity effects, have a completely better performance than far-field or high-frequency ground motions. In high-period (HP) earthquakes for short structures and in low-period earthquakes (LP) for 12-story structures, dampers have shown more energy dissipation. Based on the average of the obtained results, the effect of viscous dampers on the absorption of the input energy and reduction of roof displacement, base shear, and roof acceleration was about 90, 70, 25, and 47%, respectively.