Study On Input Energy Spectrum Characteristics Of Structural Seismic Analysis Method

The seismic response of a structure is essentially a process of energy input,transformation and dissipation,and the essential law of structural response can be reasonable revealed by energy.Since the seismic theory and design method based on energy has been put forward,it has always been concerned by the earthquake engineering.And the determination of total input energy of ground motion is the primary problem in the development of energy based seismic design method.There have been lots of researches on the input energy spectrum of ground motion,which heavily dependent on samples and assumptions,and the expression of design input energy spectrum of single degree of freedom system can not be widely recognized.Because the input energy spectrum of SDOF system is the important foundation,the influence factors and distribution law of input energy spectrum of SDOF systems are discussed in this paper,which is based on lots of more extensive ground motions,calculation and analysis.To realize these goals,the main research work and conclusions are shown as follows:（1）Theoretical deduction and analysis program of input energy spectrum.Based on the basic principle of energy response and time history analysis of single degree of freedom system,the programs of input energy spectrum and related seismic parameters of elastoplastic SDOF systems are completed on MATLAB.（2）The fundamental law of the input energy spectrum and the model selection.The fundamental law of input energy spectrum on three kinds of site conditions is analyzed,which lays the foundation for the study on design input energy spectrum.Based on the characteristics of the input energy spectrum distribution,the research method of the input energy spectrum is proposed,259 ground montions after abnormal records screening are determined as the research samples,and the three stage input energy spectrum model is adopted.（3）The design input energy spectrum for elastic SDOF systems are proposed.The input energy spectrum are equivalent to the products of_max（the peak value of input energy spectra）and normalized input energy spectrum.Through correlation analysis,the seismic parameter_se and its attenuation rule is proposed to determine_max for different situations.And combining_max with the normalized design input energy spectrum,design elastic input energy spectrum on different site conditions can be obtained.（4）Calculation method of design input energy spectrum for elastoplastic SDOF systems.Based on a large amount of elastoplastic analysis data,the influence of damping ratio and ductility coefficient on the input energy spectrum is studied,and the method to determine the input energy spectrum of elastoplastic SDOF systems is proposed.