Theoretical Studies And Experimental Analysis On High-rise Isolated Building Structure

Seismic isolation technology as a simple and effective vibration reducing technique has been widely applied to various mid-rise or low-rise buildings, and has made a good vibration reducing effect. Recently, this technique has been gradually applied to high-rise buildings, however, high-rise isolation system is particular compared to the conventional isolation system. Tensile stress will appear at the isolated bearing under strong earthquake, because height-width ratio is relatively large and overturning effect is obvious in high-rise buildings. It is an imperative problem to avoid and reduce the tensile stress in the isolated bearing. Currently, model with equal tensile and compressive stiffness in vertical of isolated bearing element is commonly adopted in high-rise isolation design, however, this model will amplify the tensile stress in isolated bearing, which is danger for high-rise building. Therefore, model with bilinear tensile and compressive stiffness of rubber bearing is adopted, and the influence of vertical stiffness on tensile stress of isolated bearing is studied in this thesis. Moreover, pseudo-static test of isolation structure with large height-width ratio is conducted to verify the vibration reducing effect of high-rise isolation buildings.The major studies about high-rise isolation buildings are as follows:1)Mechanical properties of conventional isolation devices are studied; a revised model of high-rise isolated bearings is suggested; and finite element model is established. Then, the basis is provided for design of high-rise isolated buildings and parameters optimization of isolated layer.2)The stability problem of column-cap isolation system with rubber bearing and R/C column in series is studied, and the influence of pull beam in isolation layer on structure stability is analysed.3)According to the optimization of column distance and shear wall's distribution of upper structure in the high-rise isolated buildings, and the optimization of vertical stiffness model of rubber isolated bearings, the distribution principle and the vertical stiffness model are discussed, which are in favor of the high-rise isolated buildings. Then, the vibration reducing effects are analysed comparatively.4) Model test of large height-width ratio isolated structure has been designed, and the pseudo-static test is conducted. The tensile and compressive stiffness of rubber isolated bearings in vertical is analyzed under shear-compressive condition, and the result of 3D finite element analysis by ETABS is analysed by compared with the testing result. Finally, the results of the above studies are briefly summarized in this thesis, and the derection and specific work of further research are suggested.