Study On The Energy Based Displacement Prediction Of Super High-rise Buildings Subjected To Long Period Ground Motion

In recent years,with the development of economy,a large number of high-rise building with the long-period structure was construction. In recent years there have been several strong away from the epicenter of the high-rise buildings have long time of rapid swings and even serious damage. A number of studies have shown that: long period under the action of earthquake,the dynamic response of high-rise buildings,especially displacement and inter story displacement,significantly more than ordinary high,intermediate frequency under the action of earthquake response. "Resonance effect" in high-rise building has undergone considerable deformation, structural dynamic response has been far beyond the expected design. With the deepening of structural seismic theory research,at present on seismic damage of structures is more consistent view is: Based on the maximum bit In beyond the first transfer reaction for the first time beyond and plastic accumulative damage of double failure criteria compared with the damage and the actual test. The study showed that the short periodic structure,the structure is more prone to damage accumulation and failure,and for a long period structure,the largest displacement damage may be more. In fact,the earthquake caused by structural deformation is the structure and non structure component failure of the main reasons,deformation index than strength / force index can reflect the structural seismic performance has become a consensus. Estimation of inelastic displacement demand is based on performance / displacement seismic design key first step. At present,the engineering is widely used in the response spectrum method to calculate structure Displacement, the our country also does not have through the response spectrum theory to estimate the super high-rise buildings in the elastic plastic displacement demand conditions, and the time history analysis method is very time-consuming and difficult in project popularization and application in large area. Current response spectrum method can not meet the design of high-rise building prediction,time history analysis method is time-consuming and laborious,energy response and energy conversion form is simple,convenient in calculation,and can better reflect the ground motion intensity,spectral characteristics,especially duration of strong earthquakes on the combined effect of structural damage. Therefore,this paper uses energy method to analyze the long-period ground vibration of high-rise structure displacement response through the indexes of energy and displacementrelated.The aim is to find the energy index which is related to the structural displacement response. The maximum displacement of the structure can be indirectly predicted by the energy index, which lays the foundation for the performance /displacement based seismic design.This paper using SAP2000 to make Miranda model based on established five simplified high-rise model(50 floor, 75 floor, 100 floor, 120 floor, 150floor). Through the existing research on some characteristics of the far-field long-period ground motion, formulated the far the long-period seismic wave selection wave principle,selected from 20 far-field long-period ground motions, and to make correction and adjustment. Through time history analysis of each model the maximum top displacement and maximum inter story displacement, and maximum kinetic energy,potential energy, maximum input, maximum damping energy dissipation, maximum top displacement moment of instantaneous input energy, instantaneous kinetic energy,instantaneous potential energy, instantaneous damping energy of the eight energy index were obtained correlation between maximum top displacement and the maximum inter story displacement and the eight energy index, with the changing model of damping than(0.01,0.02,0.03) of the to study the influence of damping ratio on the relevance. The main work of this paper and conclusions are as follows:1、to determine the far long-period seismic waves the wave principle, according to the principles of selected 20 far-field long-period to vibration, and the ground motion is corrected.2、using Miranda model, the model of super high rise building with five different heights(50 floors, 75 floors, 100 floors, 120 floors and 150 floors) was established by using SAP2000.3、five models are respectively input to 20 long period ground motions, and the time history analysis is carried out to obtain the maximum displacement and the maximum inter story displacement and the 8 energy indices of different damping ratios.4、Indexes of energy and displacement correlation analysis. The research results show that: 1) the maximum input and maximum damping energy dissipation and the maximum vertex displacement associated with poor, not suitable for as a predictor of the vertex displacement is the biggest energy index; 2) different self vibration period and different damping ratio under the condition, the maximum kinetic energy and the maximum top displacement correlation well(the correlation coefficients were above0.85), maximum kinetic energy for as energy index to predict vertex displacement; 3)the maximum potential energy, the instantaneous input can and the instantaneous energy dissipation and the maximum top displacement correlation with the cycle of increasing correlation decreases, unable to maintain in a stable value; instantaneous kinetic energy, Instantaneous potential energy and the maximum top displacement correlation scattered and great change; 4) maximum inter story displacement andmaximum input energy, maximum kinetic energy, the correlation between the maximum potential energy and the maximum damping energy dissipation are very poor. Relatively speaking, the maximum damping energy dissipation compared to the other three correlation better.