Study On Long-period Ground Motion As Checking Input For Supper High-rise Building

Seismic damages show that the basin site effect will enlarge the amplitude of the ground motion induced by long distance subduction zone earthquake and large crust earthquake.Thus,long distance source may induce destructive ground motion to high-rise structure.Because of the particularity of far-field long-period ground motion of seismogenic mechanism,traditional seismic hazard analysis do not have the ability to predict far-field long-period ground motion both in attenuation or in latent source division.Far-field long-period ground motion is different from the characteristics of long period response spectrum.Increasing the amplitude of the design response spectrum within long period range can not solve the long-period ground motion input,instead,it will bring many problems,such as the inconsistency among different seismic fortification levels.For the super high-rise structures built in basin,in addition to the design in accordance with the existing codes,providing additional checking calculation based on far-field long-period ground motion input for the supper high-rise building is a feasible strategy.While providing additional checking calculation based on far-field long-period ground motion input for the supper high-rise building is a systematic project,which need deep research on identification,engineering characteristics,input method,and structure analysis.The main work and the innovative achievements of this article can be summed up in the following 4 aspects:(1)Study on the method of discriminant of far-field long-period ground motionThe discriminant criterion considering seismic coda excellence and the predominant period of far-field long-period ground motion was proposed.In this paper,the characteristics of the significant surface wave dispersion of the long field long periodic ground motion are mainly used,and the remarkable cycle of the typical long field long periodic ground motion and the peak contribution of the tail band dominated by the surface wave are statistically analyzed,and the quantitative criterion for the long field long period seismic motion is obtained.The discriminant criterion of long-period ground motion is able to select far-field long-period ground motions which are according to the formation mechanism of far-field long-period ground motion,and it can provide reference for the study of ground motion characteristics and the formation of input library.(2)Study of pulses governing structural response in far-field long-period ground motionIt is pointed out that the control ground motion of long field long periodic ground motion is a pulse family with the same frequency,and the relationship between the characteristics of the long field long periodic earthquake and the structural response and the failure mechanism is clarified.In order to extract the pulse family,a wavelet-based successive frequency-dependent pulses extraction method based on the wavelet transform is proposed.By analyzing the correlation between the extracted pulse family and the structural elastic and elastoplastic response peaks,it is found that the instantaneous resonance of the pulse group and the structure in the long field long periodic ground motion is the main reason for the peak of the structural response.The effect of long time periodic ground motion on the response time of a super tall building depends on the frequency characteristics and excellence of the impulse family at the end of the seismic wave.(3)Study on the checking input of far-field long-period ground motionA long field long term ground motion input method combining the large magnitude far-field seismic hazard analysis with the basin amplification delay effect is put forward.Among them,the seismic hazard analysis of the large earthquake magnitude far field only considers the influence of large potential sources outside the scope of the safety assessment,and the attenuation relation is the attenuation relation of the horizontal bedrock acceleration response spectrum in China,and the time delay effect coefficient of the basin is mainly derived from the data of the seismological records of the stations in the large sedimentation basins in Japan.Statistical analysis results.This method takes into account the influence of magnitude,epicentral distance,basin effect and engineering site.It is a method to simulate the long field long periodic ground motion of the basin site.It can be used to determine the response spectrum of the long field long period ground motion and the time history of the ground motion in the design of the domestic engineering.(4)Study of the response characteristics of high-rise building subjected to far-field long-period ground motionThe structure and non-structure response characteristics of the high rise buildings in China under the long field long periodic ground motion were analyzed based on the input method of long period long period ground motion proposed in this paper.Taking Xi'an city as an example,a super high rise steel structure model with a basic period of 6 seconds is designed based on the given site refer to a actual structure.The code input and far-field long-period ground motion input were determined by code spectrum and the input method of far-field long-period ground motion.The elastic response,elastic-plastic response,non-structure component response and crowd panic degree of super high-rise steel structure model are compared and analyzed through time history analysis,.Through the research on the response characteristics of the high-rise structure designed by code of China,which was subjected to the far-field long-period seismic with a given probability level,it can be found that the safety of the structures built in basin can be guaranteed.However,we should pay attention to the cumulative damage of structural components,the damage of non-structure components,and the panic of the residents in the upper floor.