Research On Variable Stiffness Of Isolation Technology Test Of High-rise Building

Good performance of Seismic-isolation with laminated rubber beating isolators is the key to realizing isolation design, developed a series of seismic isolator characteristics of variable stiffness to meet the demand of stiffness and rare earthquake of different stage is of great significance for seismic isolation design. The existing seismic isolation design objectives for reducing seismic force, rare earthquake isolation layer deformation and bearing capacity control, but the existing seismic isolator and friction sliding bearing is refers has gradually reduced or single horizontal stiffness, In accordance with the small earthquake with100%shear stiffness design, to the rare earthquake the horizontal stiffness of sesmic isolator will be less than the initial stage, while the more important is to control the isolation layer does not produce large deformation and bearing had no obvious tension.At the same time small earthquake should also have the minimum stiffness to resist wind loads. However, if the use of seismic isolator stiffness with rare earthquake will drastically reduce the seismic isolation effect small earthquake. So the design of this the two stage will have a certain contradiction. Therefore, this paper developed two has the characteristic of variable stiffness, seismic-isolator of Series connection, the seismic isolator with small earthquake small horizontal stiffness. To moderate or goal the stiffness will increases, the stiffness of small earthquakes with good isolation effect, horizontal earthquake greater stiffness, and reduce the isolation layer and the upper structure of the overall target displacement. Secondly, developed a with friction energy dissipation and can variable stiffness of laminated rubber bearings. The parallel combination of seismic isolator is composed of the inner isolator, the outer ring friction plate and the outer ring isolator together, in small horizontal displacement from the inner ring isolator provide small horizontal stiffness and damping force, the outer ring isolator free sliding; When reach the target displacement, the inner and outer ring isolator together provide horizontal stiffness, stiffness values greater than the initial stage, the friction plate is in a stationary state. Experiments show that, during the whole experimental process for inner and outer ring joint bearing vertical load. Through a full-scale bearing test of the above two kinds of variable stiffness isolators, isolated high-rise buildings shaking table test, elastic and elastoplastic dynamic analysis and research, the main innovation work and achievements are as follows:1. Study and design a series combination of seismic isolator characteristics of variable stiffness, and a full-scale test research. Experiments show that, the series combination seismic isolator have good mechanical properties. Before the variable stiffness of horizontal shear stiffness and bearing support is more close to the small sesmic, Than the target displacement, combined isolator stiffness is equal to a larger isolator stiffness. A series combination of vertical stiffness of support can take two isolator series calculation, the test results show that the calculated value is very close to the test value.2. Study and design seismic isolator of parallel connection, this kind of isolator has level of variable stiffness, lead consumption, friction energy dissipation characteristics, and has better vertical bearing capacity. The initial stage of deformation by the inner bearing provided small horizontal stiffness, outer ring free sliding bearings, the friction plate friction energy dissipation. When reach the target displacement, the inner and outer ring isolator together provide horizontal stiffness, stiffness values greater than the initial stage, the friction plate is in a stationary state. The experimental results show that the motion process of inner and outer ring isolator can bear vertical load together.3. Intensive study of the applicability and technical characteristics of seismic isolator mechanics analysis model, according to the variable rigidity bearing test conclusion, fitting for calculation of computational model for the series and parallel variable stiffness of seismic isolators.4. Completed three groups shaking table test of16layer reinforced concrete frame structure which with the ratio of1:10. Three groups of models were constructed using series seismic isolator, seismic-isolation with laminated rubber and seismic isolator of parallel connection. Comparison of three kinds of different isolator actual isolation effect and the failure mode, effects of different spectrum characteristics of seismic wave, both direction effect of ground motion input degree of isolation structure. Through the completion of the first vibration of high-rise reinforced concrete frame structure test for practical engineering application provides design suggestion.5According to the shaking table test, elastic time-history analysis and elasto-plastic time were completed to test models, Elastic analysis of isolation layer by nonlinear model, and structurel elerents above the isolation layer is assumed to be elastic. At the same time, based on the fiber model considering the plastic analysis of the overall nonlinear deformation were completed. Comparison of two kinds of computing difference. To further validate the actual effect of fitting the calculated hysteretic model.