Research On The Seismic Design Parameters Of Structures With Viscous Damped Bracings

The vibration-reduction principle of viscous damper is to consume most portion of the input energy by viscous damping material during the earthquake and wind so as to diminish vibration response of structures and insure structures' safety, And this technique has been becoming one of the main tendency of earthquake-resistant engineering research. Now there're more attentions upon development, mechanics performance, computation module, dynamic analytic method of dampers at home and abroad for research on the energy-dissipation structures with viscous damped bracings, But research on conceptual design principles and additional damping ratio's determination are less and only localized in terms of the principle which restrict the expansion and application of the energy-dissipation earthquake-reduction technique. Therefore, It's very necessary to do some research on the seismic design parameters of structures with viscous damped bracings.Based on a lot of data and documents, the following key issues are approached which are tightly united with practical engineering in this paper:1. The effect of different structure types on earthquake-reduction effictiveness of viscous damper is studied and it's concluded that the higher structure and the weaker rigidity make the earthquake-reduction effictiveness of viscous damper better. At the same time, Based on calculations and analysis, some suggestions are given on how to choose proper seismic structure type for different buildings which are under different seismic design intensity.2. The arrangement of damped bracings has obvious effect on earthquake-reduction effect of viscous damper. So the effect of damped bracings on structural seismic performance is approached from these aspects: the effect of damped bracings on column axial force, geometric form of bracings, vertical layout of bracings and spatial arrangement. Then the best arrangement principles of damped bracings are given and the reasonable layouts which can control structure torsion efficiently are analyzed preliminarily by random vibration theory.3. Combined with practical engineering, the behavior discriminations between nonlinear and linear viscous dampers are compared and the effect of velocity exponent on earthquake-reduction effictiveness is studied. It's concluded that nonlinear viscous damper is better for structure earthquake-reduction.4. Based on energy equivalence and power equivalence method separately, the additional damping ratio formula of nonlinear viscous damper is derived and it's suggested power equivalence method is more suitable for nonlinear viscous damper. Then the transforming equality between actual and spectra velocity of structure is derived, based on which, the additional damping ratio equation is revised. It's indicated that the revised formula can predict dynamic response of practical energy-dissipation structure more accurately.5. Based on the theoretic analysis, two practical energy-dissipation buildings are designed and the seismic design methods are summarized.