Effect Of Isolation And Long Period Ground Vibration Of Super Large Cooling Tower

With the rapid development of China’s economy,the construction scale of power stations is increasing,and the supporting cooling towers are also becoming larger and larger.However,the traditional seismic design is difficult to achieve economic and safe effect for the super-large cooling tower structure in high intensity area.Therefore,the isolation technology is considered to be applied to the super-large cooling tower structure.On the other hand,more and more attention has been paid to the seismic response of isolated structures caused by long period ground motion.Based on the above two points,this paper takes the super-large cooling tower,an important supporting facility of nuclear power station,as the object to study the following three parts:(1)Firstly,based on the theoretical method of isolation design,the preliminary isolation design of the super-large cooling tower structure studied in this paper is carried out,including support selection,parameter calculation,support displacement checking calculation and base shear calculation based on the bottom shear method.Then the simplified element division method is used to calculate the wind load of the cooling tower structure.(2)The FINITE element numerical analysis model of super-large cooling tower was established by SAP2000,and its correctness was verified by the calculation and analysis of the model structure.Isolation analysis and calculation of cooling tower model,including the isolation vibration mode before and after the period compared with base shear,acceleration,stress and displacement,internal force on pillar,contrast,and the isolation bearing calculation,the calculation results show that the base isolation earthquake can effectively extend the natural vibration period of super large cooling tower structure,reduce the base shear,pillar internal force and the cooling tower shell have different amplitude decreases,and a series of response and for calculating the isolation bearing can satisfy the requirements of specification.The feasibility and effectiveness of the application of the base-isolation technology in the super-large cooling tower structure are verified.(3)On the cooling tower structure of the earthquake isolation structure response under seismic wave input for a long period of calculation and analysis,to explore the long period ground motion on the earthquake isolation the influence of cooling tower structure,the results show that the cooling tower after an earthquake in the structure of the long-period seismic wave input response than ordinary seismic waves,and with the improvement of fortification intensity,the cooling tower the extension of natural vibration period,after an earthquake isolation structure response under long period ground motion has a increasing trend,isolation effect is reduced.(4)The seismic response of the cooling tower shell was investigated by using the numerical model of the super-large cooling tower established by l S-DYNA,the display dynamic analysis software.The results show that the dynamic response law of LS-DYNA cooling tower structure is the same as that of SAP2000 analysis,which provides a research method for further analysis of cooling towers.