Nonlinear Analysis Of Eccentrically Braced Steel Frames With Viscoelastic Damper

The engineering structure vibration control is always the hot topic in the seismicfortification techniques area. Many scholars do their researches on how to dissipate energyand reduce seismic responses more effectively in high-rise buildings. This thesis bases onthe concept of dissipating energy and reducing seismic responses, and applying theseequipment--viscoelastic dampers to the senior eccentrically braced steel frames, theequipment belongs to the applications of energy dissipation technology. As a typical passivecontrol of energy device，viscoelastic damper, with the help of its particular viscoelasticmaterials, can increase the frame’s damping ratio, dissipate the frame’s massive inputseismic energy and consequently reduce the frame’s seismic response. There are manyadvantages of viscoelastic damper: simple structure, cheap material and easy maintenance.This technology has been widely used and its prospect is cheerful.Firstly, this thesis introduces the development of the researches on eccentrically bracedsteel frames and viscoelastic damper inside and outside China. With the purpose ofchanging the single energy consumption mode, the author combines these two technologiestogether to study the seismic performance. The author further elaborates the mechanicalproperties of viscoelastic material and viscoelastic damper, and then discusses the designmethod of setting viscoelastic dampers of the eccentrically braced steel frames.Finally, the author builts two groups of eccentrically braced steel frames, type K andtype Y, and uses finite element analytical software SPA2000to do nonlinear time historyanalysis. The analysis was done respectively in three different groups of seismic waves. Italso compared both its advantages and disadvantages. According to the results ofcomponent internal forces and structural displacements, the analysis illustrates thedifference. In addition, the author analyzes the influences on seismic performances ofviscoelastic dampers in different installations, links’ length and damping coefficient. Theconclusion can be drawn as following: different installations can impact significantly,viscoelastic damper ought to be done uniformly and continuously; the links’ length shouldbe shear yielding and damping coefficient should be within a reasonable range. The resultswere very useful and could be references for engineering design.