Key Seismic Absorption And Isolation Technique Of The Kun Ming New Airport Station-Isolation Effectiveness Research On The Upper Flexible And Under Rigid Structure

The Kun Ming new airport project is a national major project which is invested by Kun Ming government since 2007. The fund invested in is nearly 20 billion yuan. It will be one of the most large-scale airports in China after its accomplishment. The airport station is no doubtfully the most important part in the entire project. The airport station is located in Kun Ming city, its seismic fortification intensity is 8 degree, and only 9 kilometers away from Xiao Jiang fracture zone, the seismic performance of the airport station is a focal point in public's concern. After times of demonstration, seismic isolation system is finally decided to apply on the airport station building, and totally 17124Φ1000 rubber pad will be used. After its formation, the airport station will be the biggest and the most complex isolation structure in the world. Applying seismic isolation technique on this special structure is not only unique in China, but also in the whole world. So, it makes great theoretical and practical sense in researching on it.Structural system of Kun Ming airport station is very special, it is RC frame & shear wall system in the under 5 floors and long-span steel frame system braced by steel streamer in the upper steel part, the height of upper steel part is 3 times more than the under part's, however its mass is only 1/30 of under part's, its stiffness showed the characteristic of upper flexible and under rigid. Therefore, it is essential to research the seismic isolation effectiveness of the upper flexible and under rigid structures.This paper is based on the project progress, finite model of the airport station building is established by the FEM software ANSYS. Then static analysis and modal analysis are carried out, and the conclusion is compared in order to prove that the ANSYS model is available. Spectrum analysis and transient analysis on frequently occurred and seldom occurred earthquake are also proceded by using APDL command stream. Provide a formula result of different model using different mechanical software, offered effective sustainment for engineering design, and the rationality of isolation design scheme is certificated.Furthermore, focused on the upper flexible and under rigid characteristic of Kun Ming airport station, some pertinencial researched are carried out. The airport station building is simplified to a double-mass-system. The model is calculated by using the software of 3D-BASIS-ME, the influence rule of the variation on the isolation stiffness to the earthquake response of superstructure is discussed, concluded that:The more severely upper flexible and under rigid structure is, the more twice acceleration ratio is and the more whip-tip effect is. Compare to the non-isolation structure, applying seismic isolation technique on upper flexible and under rigid structures can effectively reduce the acceleration response and twice acceleration magnificent, the potential suddenly increment of twice acceleration magnificent for the isolation stiffness variation is not occurred, the relationship between structural acceleration response and variation of isolation stiffness is almost linear.