| Significant improvement has been seen in Modern Anti-Seismic Theory in recent a century,and the number of deaths due to earthquakes has been effectively controlled.However,the global crustal movement has become more active since the beginning of this century,and the global economic losses caused by earthquakes have risen.With the Proposal of the performance-based seismic theory,the demand for building's ability of suffering earthquake has been transforming from reducing casualties to ensuring minimizing casualties while reducing the economic losses in the earthquake as much as possible.By now,methods based on performance-based theory has been developed for nearly 30 years and methods based on energy,which is one of them,has been gradually recognized by researchers.Chinese scholars have also made relevant researches on energy-based seismic theory and proposed several energy design spectrum forms.However,these studies about design spectrum are not based on Chinese strong motion data,and thus whether it is fit to represent Chinese seismic situation is not clear.This study has selected strong motion data which is recorded in China's mainland in past 10 years,and calculated the input energy spectrum of the seismic records based on the methods of energy analysis.Energy Design Spectrum for Site-I and Site-II has been fitted,and the influence of structure's damp ratio,second stiffness ratio and ductility factor on energy spectrum has been discussed.The selection of ground motion input when designing based on the energy design spectrum has been discussed,by combing “The Severest Design Ground Motion” method with the theory of PSHA,and records has been selected by the exceedance rate of input energy.The specific contents of this study are as following:1?The data set is based on China mainland's strong ground motion records,all records are classified according to the site conditions and the process of the baseline correction of records has also been performed.2?The form of ground motion parameters and input energy of ground motion has been introduced in detail by discussing the characters of ground motion.The correlation between input energy and GM parameters has been discussed and 7 parameters have been picked out as ground motion's representative parameters.The feasibility and rationality of input energy being a design index has been discussed by study the correlations between input energy and the structural response parameters of SDOF & MDOF.3?Energy design spectrum for Site-I and Site-II has been fitted by records' input spectrum and found that difference of Data set in crust has a significant influence on design spectrum,which proved the importance of native ground motions on fitting results.Meanwhile,the influence of damp ratio,second-stiffness ratio and ductility factors on spectrum design has been discussed and finally get the equation form of input energy.4?The selection of input ground motion has been performed by combining probability seismic hazard analysis theory with the ‘Severest ground motion selection method'— by quantifying the attenuation model of input energy,annual activity rate of seismic zones,the probability distribution function of epicenter distance and the input energy's conditional probability,and finally,this study got the cumulated probability function of the input energy.By calculating the input energy values corresponding to different guaranteed probabilities,the unfavorable ground motion records with probability guarantees for different regions are selected. |
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