Study On Design Method And Performance Of Foundation Isolation Frame Structure University Of Science And Technology Liaoning

The essence of foundation isolation is that the deformation of seismic isolation support after earthquake occurs to cancel the seismic energy to a great extent,which reduces the seismic action of the above structure of the isolation storey,and at the same time extends the self-vibration period of the structure to avoid the site predominant period.Because the foundation isolation technology has a good isolation effect,our country began promoted vigorously,but there are still some problems in the application of practical engineering.Firstly,this paper has been introduced the principle of isolation,the type of support and the mechanical properties,and made a brief analysis of the dynamic analysis theory of the foundation isolation structure.Then the basic isolation frame and non-isolation frame of the five-storey frame are designed by Sap2000 software,and an artificial wave and two natural waves are used to analyze the modal time history and compare the vibration pattern,period,interstorey acceleration,storey shear force,substrate shear force,etc.To determine the effect of the isolation frame.In addition,a convenient design method has been proposed using equivalent Linearization method combined with Vibration Decomposition reaction Spectrum method.Verify that precision requirements are met through three basic isolation frame design.Finally,the overstrength performance of the base isolation frame structure is explored by pushover analysis,and the Pushover analysis method of the basic isolation frame structure is given.The accuracy of this method has been verified by comparing the results of time history analysis in middle and rare earthquakes.By calculating the overstrength factor of each frame and summarize the related research to get the overstrength law of the isolation frame.Based on the performance indexes such as displacement of isolation storey,displacement angle of storey and plastic hinge state of component,the evaluation standard of performance target suitable for basic isolation frame is established.The main conclusions of this paper are as follows : in this paper,the effect of the foundation isolation frame reducing earthquake is obvious,and meeting national norms to reduce once-earthquake requirements can be designed in accordance with the 7-degree earthquake(0.1g).The scope of application of the design method proposed in this paper is as follows : in the higher number of storeys(greater than 6 storeys)requires a combination of time-history analysis to envelope the structure design.This method can be used directly when the deformation of the isolation storey is in the elastic range or the number of storeys is less than 6 storeys.The method of Pushover analysis has been separated from the isolation storey and the superstructuresatisfies the precision requirement.Some examples has been adopted to determine that the overstrength factor of the foundation isolation frame structure is 2.0;Quantitative values of overstrength factor and plastic hinge state after comprehensive analysis,Then combined with the importance of the building classification,the performance objectives of the foundation isolation frame structure are divided into intact,minor damage,life safety and will be close to collapse.Analyzing the basic isolation frame verifies that the evaluation system satisfies the rationality.