Analysis Method Of Displacement And Energy Responses For Evaluating The Performance Of Seismic Structures

On the basis of performance based design, which is discussed widely in theworld, the work of the paper aims at the displacement and hysteretic energy responsesof seismic structures. The state of arts is reviewed and the disadvantages of theperformance based design are expatiated and the research trends are presented. Theanalysis methods of displacement and hysteretic energy responses of seismicstructures are discussed and mainfindings are listed as follows: 1. The structural dynamic parameters and earthquake parameters which haveeffect on response spectrum are analyzed fully based on the investigation of thedisadvantages of the method of equivalent high damp ratio elastic demand spectrummainly used for evaluation performance of seismic structures. The elastoplasticacceleration spectrum, elastoplastic displacement spectrum and the ratio spectrum ofthe elastoplastic displacement to the elastic displacement are calculated in statisticalsense by using a great deal of earthquake digital records with time history analysismethod. The simplified formulas of these spectra are set forth. The improve capacityspectrum method based on the elastoplastic demand spectrum and method forcalculating yield displacement are founded. Anew approach of the performance baseddesign is provided with the improved capacity spectrum method. The applicability ofimproved capacity spectrum method in seismic engineering is proved by theexamples. 2. The suggestion of appending the capacity of hysteretic energy responses in theevaluation of the performance of seismic structures is proposed to solve the problemwhich the performance and capacity of seismic structures cannot be accuratelyevaluated by only considering the displacement response. The total input energyspectrum and hysteretic energy responses spectrum and the ratio spectrum of thehysteretic energy to the total input energy are calculated in statistical sense based onthe analysis of the influence of the earthquake parameters and structural dynamicparameters on the spectrum. The simplified formulas of these spectra which areprecise and can be conveniently used forengineering purpose are regressed. The earthquake ground motions are classified by considering the duration ofthem and the displacement time-history and hysteretic energy increment response ofSDOF are calculated. The relationship between the maximal plastic displacement and III英文摘要hysteretic energy increment for different types of earthquake ground motions arefound which can solve the problem that the structural global ductility can only becomputed approximately rely on the method of monotony loads and that can also bethe basis of the integrated evaluation of the capability of seismic structures. The energy response of bar system of frame structures which are subjected tolong duration type waves, middling duration with multi-frequency components typewaves and short duration impulse waves with the intensity of 7 and 8 degree areanalyzed respectively. The results show that the energy response discrepancy is a fewtimes, and in some cases may be ten times. For the stories of weak resistance capacity,both the displacement and hysteretic energy should be checked in seismic designbased on structural performance. The hysteretic energy amount should be consideredwhen judging whether the structure is damaged. The suggestion, which hystereticenergy dissipated by beams and girders should be taken into account when the failurecriterion is determined by displacement and hysteretic energy amount, are presented. 3. The method of selecting input earthquake waves in which the duration isrequired to be considered in the analysis of hysteretic energy using time-historyanalysis is discussed. The method of selecting input earthquake waves based onhysteretic energy response by using total input energy spectrum is suggested. Theadvantage of the method proposed is simple, definition and convenience...