| Seismic isolation technology can greatly improve the seismic performance of structures and is widely used at home and abroad,but at present,seismic isolation design methods must use multiple seismic waves to analyze the time history under fortification earthquake to determine the isolation effect.As a static nonlinear method for seismic performance evaluation of structures,the Pushover analysis method has the advantages of simple and fast,and has more application value for seismic performance evaluation and design optimization of isolated structures.However,the current Pushover analysis and application research is most used to the traditional seismic structures but rarely in isolation structures.In the future,school buildings applicated seismic isolation technology will become the hot spot,based on this,this thesis takes the RC frame isolation structure as the main research object.Firstly,explored the appropriate Pushover analysis method and verified by nonlinear time-history dynamic analysis.The effectiveness of this method for rapid design verification and optimization of isolation is discussed.At the same time,the seismic performance of RC frame isolation structures under rarely and even rarely earthquakes is confirmed.Firstly,by using two different loading modes: inverted triangular loading and uniform loading the Pushover analysis of RC frame non-isolated structures with 5 layers and 7 layers in high intensity region is carried out,and the nonlinear time-history analysis of large earthquakes is carried out by selecting 7 seismic waves(2 artificial waves and 5 natural waves),compared and analysis of the results.The results show that: the Pushover method of inverted triangle loading is more accurate than the uniform loading for RC frame non-isolated structure,which can meet the precision requirement of the seismic behavior analysis results under the rarely earthquake.Then the corresponding model of 5 and 7 layers RC frame isolation structure is compared and analyzed.The results show that: the Pushover analysis using uniform loading mode is consistent with the nonlinear dynamic time-history analysis for RC frame isolation structure in such as inter-story displacement and displacement of isolation layer.Compared with the inverted triangular loading mode,the uniform loading mode of the Pushover method is obviously more accurately,which model of seismic isolation can meet the requirements of seismic performance evaluation under rarely earthquakes.Compared with the non-isolated structure,the inter-story displacement and shear force of the isolated structure are greatly reduced,and the seismic performance of the superstructure is still in the basic elastic state under the rarely earthquake.Using Pushover analysis method with uniform loading is an effective method for evaluating seismic performance and optimizing design of multi-layer RC frame isolation structures.Considering the requirement of "giant earthquake not falling" in some important buildings,the Pushover analysis method is used to check and calculate the RC frame isolation structures with even rarely earthquake.The results show that the displacement calculation of the fivestory structure isolation layer does not meet the requirements,and the seven-story structure content the requirements.This indicates that the horizontal limit deformation capacity of the support may be a key factor in the design,and there is a risk of isolation layer failure.Finally,the difference of seismic performance between non-isolated and isolated structures with 5 and 7 layers of frame is compared.In the even rarely earthquake,the 5 and 7 layers of non-isolated structures collapsed,and the corresponding isolation structure is only in the degree of moderate breaking,fully realize the "giant earthquake does not fall ",to ensure the safety of life and property to the greatest extent.And also verify effectiveness of Pushover method for design checking,optimization design and seismic performance evaluation of isolation results is presented. |
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