Dynamic Time-History Analysis And Reliability Study Of Interlayer Seismic Isolated Structure System

In earthquake-isolation buildings, the earthquake isolation devices are normally settled between the top of the foundation and upper structure and the technique is called base isolation. With the development of researches on the base isolation and deeper insights into the applications of this technique, its shortcomings, which have limited the techniques of earthquake isolation, begin to emerge. Then came into being the interlayer seismic isolated technique with seismic-isolation bearings are set up between the floors of the building. In accordance with bearings in the layer between the different positions, this new technique research is divided into middle layer seismic isolation and roof seismic isolation. The focus of this paper is to study the damping effect and reliability of the middle layer seismic isolation, i. e. the seismic response is controlled by setting up the isolation layer between the columns in the first floor and second slab. Middle layer isolated structures is different in many aspects from the base isolation structure and roof isolation structure in vibration characteristics, damping mechanism, as well as design method.The mechanical property of bearings is discussed in the paper. Furthermore, the finite element simulation model is established for the interlayer seismic isolated structure and the dynamic equilibrium equation for the system is deduced theoretically. By taking a 12-story shear-frame structure as an example and introducing the theory of reliability, the dynamic time-history seismic analysis for traditional anti-seismic structure and interlayer seismic isolated structure are performed using ANSYS program to obtain elastic and elastic-plastic responses. The reliability of relative displacement in each floor and the total seismic isolated structural system are further calculated according to the results of time-history responses.The seismic responses for traditional anti-seismic structure and interlayer seismic isolated structure are calculated and the numerical results of the two type structures are compared. It is illustrated that the damping effect for the interlayer seismic isolated structure is efficient and the system is mainly determined by the reliability of isolated layer. Hence, the more reliable reliability can be achieved than the anti-seismic structure by adjusting the reliability of the isolated layer.