Simplified Analysis Of Base Isolation Of Light Steel Laminated Structure Foundation

In this paper,the research status of base isolation technology at home and abroad is discussed,and the simplified calculation method of base isolation for hybrid structure with light-weight steel and storey adding is discussed.Based on the experimental model of two layer light steel layer mixing structure,two simplified methods of static elastoplastic and finite element method are used to calculate the dynamic response of the base isolation of the mixed structure of the two layer and the multilayer light weight steel.The results of the simplified analysis are compared with the experimental data;At the same time,by changing the stiffness and position of the isolation layer,the parameters of the hybrid structure of the light steel are analyzed,and the influence of the stiffness and position change on the dynamic performance of the structure is discussed.The main contents are as follows:for the base isolation structure,a multi degree of freedom equation considering the structure of the earthquake is established.The equivalent mass,equivalent damping and equivalent restoring force of the structure are calculated,and the lateral force increment equation of the structure under different load distribution modes is discussed.(2)Based on the static elastoplastic method and the nonlinear finite element method,the dynamic differential equations of the two layers light steel layer mixing structure under the condition of isolation and non isolation are established.The maximum acceleration,displacement and interlayer shear are calculated,and the results of static elastoplastic calculation,the results of finite element analysis and the experimental results are compared.the study shows that the maximum error of the static elastoplastic calculation and the test results before and after the structure isolation is not more than 8%,and the error of the finite element analysis and test results is not more than 11%,and the simplified calculation is simple and effective.(3)Based on the dynamic time history method,a nonlinear finite element model of multi-storey light-weight steel storey adding structure with base isolation is established,and the dynamic response of the structure is calculated.through the comparison with the literature,it is found that the acceleration of the multilayer structure and the interlayer shear force are reduced by 27%and 16.7%respectively,and the displacement response is increased by 64%,and the structure isolation effect is very obvious.(4)Through the change of the stiffness and the isolation position of the isolation layer,the parameters of the two layer and multi story light steel layer mixing structure are analyzed,in which the stiffness ratio of the isolation layer is 0.01 to 1,the location of the isolation layer is one layer and the bottom of the light steel layer respectively.Research shows for the two layer light steel layer mixing structure,the period decreases with the increase of the stiffness ratio.The acceleration and interlayer shear increase with the increase of the stiffness ratio.When the stiffness ratio is greater than 0.1,the change tends to be gentle.For the multilayer lightweight steel layer mixing structure,with the increase of the stiffness ratio,with the increase of stiffness ratio,the shear strain and acceleration of the structure change obviously,when the isolation layer is in a high position,the shear force of the isolation layer is larger than that of the anti-seismic structure.