Study On Ground Motion Selection Of High-rise Isolated Structure Based On Simplified Model

In recent years,seismic isolation as a mature structural control technology is universal generalized and gradually applied to the study of tall building structures.The analysis and calculation of isolated structures uses time history analysis.And it is important to select rational ground motion.This thesis utilizes the simplified model which possesses the deformation and dynamic characters of high-rise isolated structures to investigate the method of selection of real records and synthetic records(time adjusted spectra matched records?artificial records).Responses of high-rise isolated structure under records selected by different methods are compared to study the effectiveness of the methods;the selection of seed records,ground motion characteristic and structure response of time adjusted records are investigated;the method of determining duration parameters of envelop function when generating artificial records is put forward,and structure response characters of artificial records are studied.The main achievements of this study are as follows:(1)Response of isolated structures come to nonlinear phase under strong ground motion,spectrum period range related to structure response is extended,only rational period range associated to nonlinear response is selected can the target of the method controlling two frequency domain be achieved,method based on the ground motion information is independent of structure dynamic characters,and can be applied to the analysis of different type of structures,rational selection and control of ground motion parameters will lead to low level of structure response dispersion.Severest design ground motion selection can pick up the records of highest damage potential effectively,and is applicable to check the structure security.(2)Time adjusted spectra matched records is helpful to reduce the dispersion and get stable results of structure response and.It is suggested to choose the records with spectrum close to target spectrum as seed records for time adjustment.It should be noted that when using design spectrum for our nation seismic code the characters of long period domain of records will be altered unrealistically,and can result in large energy response.(3)A method of determining duration parameters of envelop function when generating artificial records is proposed based on energy,and suggested duration parameters of design spectrum of different type of soil condition are provided,which can achieve the consistence of energy characters of artificial record with ground motion records.The results provide guidance for ground motion selection of high-rise isolated structures,and has great significance for performance based seismic design of building structure.