Analysis Of Roof-isolation In Space Grid Structures

At present,the seismic isolation technology has become the main form of passive control,the base isolation and shock layer spacing technology has been mature in the engineering application.But the study of the isolation of long-span space structures is still at an early stage,especially the grid structure,its many problems still exist in the practical engineering.In this paper,the design of seismic isolation layer in Roof-isolation is studied:(1)This paper adopts two kinds of simplified dynamic analysis model to study the performance of Roof-isolation.One is the predecessors put forward by the single mass point and serial spring model.The second is proposed for the practical engineering problems of double column model.According to the first simplified model,the change rule of the acceleration response attenuation ratio and the changes of frame column stiffness ratioKb/Kc,and the change rule of space truss roof by shear with isolation layer and the changes of frame column stiffness ratioKb/Kc are deduced.According to the double column model is derived that when the frame column and isolation layer series stiffness along the X or Y axis symmetric that space truss roof along the axial direction of the axial deformation is minimal.And in the case of asymmetric,it is concluded that horizontal stiffness of isolation layer method.(2)To test and verify the results of derivation,in combination with derivation results and the practical situation of engineering made two comparison methods,and time history analysis was carried out in the earthquake to these models.Comparison results show that the derived results with practical situation of engineering examples,the results of the analysis is not perfectly.But the displacement and acceleration response of the upper structure parameters with the isolation layer stiffness change trend and derivation are basically identical.Comprehensive results and analysis,found that due to the interaction between space truss roof and bottom structure is very complex,want to accurate isolation layer stiffness values,temporarily use a simplified model is unable to complete.But according to the theory of the trend chart can give long-span space structures Roof-isolation layer design with some help.