Research On Probabilistic Reaponse Spectrum And Ground Motion Parameter Spectrum Of Class ? Site

The response spectrum is the cornerstone of the structural seismic design.The response spectrum theory uses the equivalent load method to represent the effect of the earthquake on the building.The internal force and displacement of the structure are calculated by means of static analysis.This method provides a convenient tool for seismic design.Response spectrum analysis is based on the selection of suitable seismic records.Since seismic records are one of the important factors that affect the uncertainty of the system,it is very important to choose appropriate seismic records to establish the response spectrum.The main contents of this paper include the following aspects:(1)Summarizes a variety of Chinese and foreign seismic record selection method.Based on the factors such as fault type,magnitude,fault distance range,Vs30and D5-95 in controlling the environmental parameters of the site,the influence of mean square error(MSE)on the record selection is taken into account.353 seismic records are selected,49 seismic records in the characteristic period range of[0.35,0.50]are screened by FEMA450 and compare with the results of the original method.The results show that the overall dispersion of the seismic record response spectrum selected by MSE and characteristic period T_g is lower than that of the original method,a relatively small number of seismic records result in a better match with the design spectrum,and the efficiency of record selection can be greatly improved.(2)The probability distribution of elastic-plastic response spectrum at different periodpointsunder differentductility coefficientswasanalyzed by Kolmogorov-Smirnov hypothesis test.The logarithmic normal distribution,the extreme value type I distribution and the extreme value type II distribution pass rate are high,indicating that the elastic-plastic response spectrum coincides with these three distributions at each period point.These results provide the basis for predicting the distribution of spectrum values at each period point.The fitting formula of the elastic-plastic mean response spectrum of?=1,?=2,?=4,?=6 and?=8 is obtained by fitting the elastic-plastic mean response spectrum of different ductility coefficients.(3)Based on the selected seismic records,the three-dimensional spectrum of displacement,velocity and acceleration are established in three different characteristic period groups,and compared with the three-dimensional design spectrum.The dispersion of the mean spectrum and the design spectrum under four different kinds of earthquake influence are analyzed.The mean spectrum are in good agreement with the design spectrum.The next step of the study may consider the direct introduction of the velocity three-dimensional spectrum from the acceleration three-dimensional spectrum so that the velocity spectrum information can be directly obtained in the case of a known acceleration spectrum value.(4)A seismic record database with a characteristic period of[0.35,0.50]is established.Calculate the mean value of the acceleration under the influence of each earthquake.The results show that the seismic records selected by MSE and T_g have good robustness.