Research On The Characteristic Period Value Of Seismic Design Response Spectrum

With accumulation of the strong earthquake records and the experience in seismicdamage, understanding for characteristics of earthquake response spectrum, our country’sconstruction seismic code passed six times evolution. Design response spectrum curvealso experienced larger evolution, the evolution mainly reflects in feature period andresponse spectrum value unceasingly fixed. The response spectrum curve used by ourcountry now is still not mature. Feature period is the important parameters of designresponse spectrum to aseismic design calculation, has great influence. But the influencefactors for feature period are more. The research achievements in related fields arerelatively rare.This paper reviews Chinese design response spectrum evolution, and introduction ofAmerican standard aseismatic design response spectrum, based on the former, comparesthe similarities and differences between sino-us response spectrum. Earthquake databasehas been established by437strong earthquake records in the Midwest, and the database ofcoverage and availability are analyzed, the results show that the database has strongapplicability. In the influence for design response spectrum feature period value, refer to alarge number of documents, summarized the factors for characteristics period with: kindof site, magnitude, the epicenter, focal mechanism, soil structure and so on. In addition,the equivalent linearization fluctuation analysis software SHAKE91is used in threedifferent layers structure of the earthquake response analysis. The results show that softinterlayer soil profile that in the lower part, the feature period have amplification. In theside of feature period statistical value, mainly the feature period value forⅠ, Ⅱ, Ⅲ kindof site are statistically calculated, and hundreds of United States earthquake records areclassified, according to magnitude, epicenter, site classification. The influence of threefactors, like as, the site classification, the magnitude, the epicenter, on the value ofcharacteristics period is analyzed in linear regression way. Results show that differentcategories, magnitudes and epicenters, to design response spectrum characteristic valuehave significant influence. The more soft the site condition the bigger the feature period value. And feature period has good linear relation with the magnitude, but the relevance ofthe epicenter is not obvious.