Analysis Of Damping Efficiency Of Base Isolation Frame Structure

China is located between two seismic belts in the world,the Circum-Pacific seismic belt and the Eurasian seismic belt.The seismic fault zone is very active,and China is one of the countries with the most serious earthquake disasters.The 8.0-magnitude Wenchuan earthquake on May 12,2008 caused serious loss of life and property as well as damage to engineering structures in China,and a large number of residential buildings were seriously damaged.Therefore,it is of great significance to improve the ability of building structures to resist earthquake to reduce the loss of life and property caused by earthquake disasters."Three level two phase structure design method of Chinese traditional architectural structure design method,belonging to the" hard ",and the isolation design,content of building is the natural vibration period by extending the upper structure,increasing the damping structure transfer to reduce the earthquake effect,and belongs to "soft",under severe earthquake,the upper structure component won’t produce damage and non structural components,The safety of life and property is guaranteed.Therefore,this paper takes the actual engineering of a frame structure office building as the background,through setting isolation bearings in the base,and using numerical analysis as the means to carry out the analysis of foundation isolation and damping efficiency,The work and main conclusions of this paper are as follows:(1)The mechanical properties of rubber isolation bearings are summarized to lay a theoretical foundation for the simplification of the model.(2)Considering the influence of cast-in-place floor slab as flange on the stiffness and bearing capacity of beam,the size of flange section beam was determined,and a simplified nonlinear finite element model was established to analyze the dynamic time-history response.The nonlinear finite element software SAP2000 and the design software PKPM are used to verify the two models.The results show that the error of the first three natural vibration periods calculated by the two software is about 5%,which verifies that the simplified model established by the nonlinear finite element software is correct.(3)Set up three kinds of isolation structure and original structure(structure)nonlinear finite element model,the selection of a site vibration and two of the actual ground motion on the above model,large,super strong earthquakes in nonlinear dynamic time history response analysis,to explore and earthquake resistance,the rarely met earthquake under the action of the rarely met earthquake,isolation response law of the upper structure,At the same time,three kinds of isolation schemes are compared and analyzed.The research results show that three kinds of isolation scheme of acceleration response,displacement response,a number of plastic hinges and dynamic response of nonlinear degree are less than the original structure the isolation structure and original structure acceleration ratio of the maximum around 0.8,than the maximum displacement of isolation structure and original structure at around 0.70,structure the upper structure of the overall translational state.At the same time,this paper compares and analyzes the damping efficiency of three kinds of isolation schemes.By comparing and analyzing the dynamic response of the three schemes,the combined isolation scheme has obvious damping efficiency,and the damping efficiency of isolation scheme two and three is better than that of isolation scheme one.