Modeling and Investigating the Behavior of Viscous Dampers in Steel Structures

: Viscous dampers are generally effective in controlling the vibrations stemming from the wind in the steel structures as well as in excitements with frequency band identical to that of these dampers. Tuned viscous damper is a passive control system the parameters of which are determined based on the structure’s preliminary specifications and always remain fixed. The primary goal of this study is observing the nonlinear behavior and evaluating the seismic performance of the steel structures with specific steel moment frames equipped with viscous damper under mass and damping uncertainty conditions of the structure as well as in respect to the elastic modulus and yield stress in steel. This evaluation has been carried out by the assistance of ETABS and Sketch-Up Software Packages with the time history analysis having been conducted in Sap2000 Software. To do so, three steel 3-, 9- and 12-storey structures with residential use have been considered on an earthquake-prone region. The study results indicated that the storey’s drift and dislocation have been considerably reduced. Thus, it can be concluded that the use of viscous damper is an appropriate method for controlling the structures’ dislocation. It was also found out that the emergence of disorder in the structure’s mass and damping has a greater effect in contrast to the other two parameters on the response of the structure equipped with viscous damper. mechanism of action is in the form of cylinder-piston. There are three chambers inside the cylinder: one on the right side of the piston, one on the left side thereof and one in the farthest end of the right side. There are holes in the piston and there is also liquid inside cylinder which is either oil or a condensable liquid. When piston moves in cylinder, its movement causes the displacement of the liquid from the orifice positioned on the piston’s head. The movement of the liquid from amongst these holes causes the depreciation of energy or, in other words, the energy is dissipated in the form of heat.