THE USE OF VISCOUS AND VISCOELASTIC DAMPERS FOR SEISMIC REHABILITATION OF THE STRUCTURES

Strong earthquakes induce high amount of energy to the affected structures. If this energy can be controlled and dissipated in a manner independent of the structural components, the seismic performance and response of the structure will be substantially improved. This objective can be achieved by using passive control of the structures or base isolation techniques. In this study, the effect of the use of viscous and viscoelastic dampers to improve the seismic performance of an existing vulnerable 9 story steel structure has been investigated using nonlinear dynamic analyses. Each damping system has been modeled in the structure for several damping ratios and damper properties. In nonlinear dynamic analyses by the use of RAM-PERFORM3D software, the response of the structure to seven scaled earthquake records matched to the design spectrum has been obtained and the average value of the displacements, drifts and dissipated energy in the structural members have been used for the comparison. The results demonstrate that with the use of viscous and viscoelastic dampers in the structures, displacements and damages in the structure can be substantially reduced. At the same time, because these kinds of dampers exert their maximum forces in out of phase with displacement, most of the columns remain elastic.