Seismic behavior of a 2/5-scale steel structure with added viscoelastic dampers

Seismic behavior of a 2/5-scale steel frame structure with added viscoelastic dampers is studied experimentally and analytically in this dissertation. Major emphases are placed on the ambient temperature effect and the seismic structural response under strong earthquake ground motions. It is shown that, while seismic response of a structure can be significantly improved by the addition of dampers to the structure, the degree of effectiveness of the dampers depends on the surrounding temperature within which they operate. Results show that, even at the very high temperature, the viscoelastically damped structure can still achieve a significant reduction of structural response as compared to the case with no dampers added. Also, both the analytical and experimental results clearly demonstrate the superior performance of the structure installed with the dampers under severe earthquake excitations. Even earthquake ground motions with peak accelerations of 0.60 g cause no damage to the structure and dampers, while the structure without added dampers undergoes large inelastic deformations.; In order to consider all the factors which affect the properties of viscoelastic dampers in the design, empirical formulae based on regression analysis using the data obtained from damper coupon tests are proposed. These formulae can satisfactorily estimate the dynamic properties of the dampers under various ambient temperatures, excitation frequencies and deformations; The reliability of using the modal strain energy method to predict the equivalent structural damping and seismic structural response is illustrated by correlating the numerical simulation with the experimental results of the viscoelastically damped structure. It is shown that the dynamic behavior of structures with added viscoelastic dampers can be satisfactorily predicted by using currently available analytical tools.; Finally, the design procedure for the structures with viscoelastic dampers is developed based on the aseismic design rationale that the excessive story drift and inelasticity of the structure be limited during severe earthquake excitations.