Engineering Method Of Calibrating Design Response Spectrum

Since professor M.A.Biot put forward the concept of seismic response spectrum in the early 1930 s,the study of seismic response spectrum has been a history of nearly one hundred years.It has become an important method for people to analyze the characteristics of ground motion.The study of the design of response spectrum and its calibration method has also been a history of more than half a century.It has become an indispensable instrument of anti-seismic design.The study of response spectrum and its calibration method are frontier issues in the field of engineering seismic research and have attracted wide attention from academia and engineering circles.At present,there are many calibration methords of response spectrum,each has its own advantages,but there is a lack of a unified engineering calibration method.On the basis of the previous research results,this paper makes use of the strong earthquake record data from China and abroad to analyze the value range of the response spectrum platform and the value range of the characteristic period,and puts forward the engineering method of calibrating design response spectrum.The main research work is as follows:(1)The calibration principle of the design response spectrum is summarized and reviewed.The technical details of the calibration of Newmark three-parameter calibration method,double-parameter calibration method,the least square fitting calibration method and the differential evolution calibration method are introduced in detail.The four calibration methods are compared with the verification method proposed by Liu Hongshuai,and the results are verified with 18 strong earthquake records in Sichuan,Yunnan,Gansu and Shanxi areas.The results show that the differential evolution calibration method is best fitted to the seismic response spectrum.In this paper,the differential evolution calibration method is used to calibrate the collected seismic response spectrum and the corresponding calibration parameters are given.(2)According to the three factors of magnitude,epicenter distance and site conditions,the collected strong earthquake records were grouped.And the value range of the response spectrum platform and the value range of the characteristic period of each group were statistically analyzed.The characteristics of the response spectrum platform value and the characteristic period value along with the site type,magnitude and epicentral distance are summarized.(3)Aiming at the problems existing in the design engineering response spectrum calibration in the current engineering world,engineering method of calibrating design response spectrum and its work flow were proposed,and the calibration process of the new method was described.Two different sites were used as examples for application.The results show that the new method is feasible,reasonable,and convenient for engineering application,and can reflect the characteristics of the site-specific spectrum.The characteristic parameters of the site-specific spectral spectrum are the ranges of the calibration parameters.