The Isolation Structures, The Disc Spring

When earthquake happens, the vibration of the earth's surface causes the earthquake responses of structure. For structures fixed to the ground, its earthquake responses gradually become greater and greater from the bottom to the top and lead to the destruction of structure finally. To avoid the disaster, people must control the structure's earthquake responses. Generally speaking, horizontal earthquake forces play important role in the destruction of structure. But in the central area of earthquake, vertical earthquake forces may reach even exceed the horizontal forces. So in the high intensity areas, how to reduce the destroy of vertical earthquake must be considered.Base isolation system can reduce the structure's earthquake responses obviously and effectively. Its measures defending the earthquake are simple and clear. It needn't repairing after earthquake and ensures the people's lives and treasures safety.Disk spring likes a disk plate. Its ability of sustaining loads is great. It is suitable to the situation where vertical place is small and horizontal place is large. So disk springs can be used in the vertical isolation system.Dynamic absorption applies the principle of common vibration to adding TMD to structures, makes TMD common vibration to absorb the earthquake energy to reduce the dynamic responses of structure.Generally TMD is placed in the place where earthquake responses are the biggest. The biggest value of multistory structure's earthquake responses is in the top of the building, So TMD is placed in the topstory. But the biggest earthquake response of base isolation system is the isolation story, therefore isolation story. Earthquake is random action inducing varies frequency. TMD can only reduce responses of few kinds of frequency and can't realize the total absorption.The vertical stiffness of structure is big and its period of vibration is small. When isolating the vertical vibration, we must design the base frequency of isolation story small so that it can reduce the acceleration and axis force of structure. This makes the displacement big. TMD can obviously reduce the earthquake responses of isolation story. So the combination control of base isolation system and absorption energy which is used in reducing the vertical earthquake responses of structure is an effective method.