The basis for the NEHRP site coefficients is summarized in the paper. The comparison of site classification between China and US code provisions has been carried out. The relationship between two site classifications ...The basis for the NEHRP site coefficients is summarized in the paper. The comparison of site classification between China and US code provisions has been carried out. The relationship between two site classifications has been found by the analysis of wave velocity of site soil. Thus amplitude-dependent site amplification factors for China site classification has been gained by transformation from US amplification factors. Two amplification factors are specified： Fa for short periods and Fv for longer periods. On the contrast, there is only one long period factor and not a short period factor in the current China code provision.展开更多
Newmark design spectra have been implemented in many building codes, especially in building codes for critical structures. Previous studies show that Newmark design spectra exhibit lower amplitudes at high frequencies...Newmark design spectra have been implemented in many building codes, especially in building codes for critical structures. Previous studies show that Newmark design spectra exhibit lower amplitudes at high frequencies and larger amplitudes at low frequencies in comparison with spectra developed by statistical methods. To resolve this problem, this study considers three suites of ground motions recorded at three types of sites. Using these ground motions, influences of the shear-wave velocity, earthquake magnitudes, source-to-site distances on the ratios of ground motion parameters are studied, and spectrum amplification factors are statistically calculated. Spectral bounds for combinations of three site categories and two cases of earthquake magnitudes are estimated. Site design spectrum coefficients for the three site categories considering earthquake magnitudes are established. The problems of Newmark design spectra could be resolved by using the site design spectrum coefficients to modify the spectral values of Newmark design spectra in the acceleration sensitive, velocity sensitive, and displacement sensitive regions.展开更多
Calibration coefficients validation is the foundation for ascertaining the sensor performance and carrying out the quantitative application.Based on the analysis of the differences between the calibration and validati...Calibration coefficients validation is the foundation for ascertaining the sensor performance and carrying out the quantitative application.Based on the analysis of the differences between the calibration and validation,two calibration coefficients validation methods were introduced in this paper.Taking the HJ-1A satellite CCD1 camera as an example,the uncertainties of calibration coefficients validation were analyzed.The calibration coefficients validation errors were simulated based on the measured data at an Inner Mongolia test site.The result showed that in the large view angle,the ground directional reflectance variation and the atmospheric path variation were the main error sources in calibration coefficients validation.The ground directional reflectance correction and atmospheric observation angle normalization should be carried out to improve the validation accuracy of calibration coefficients.展开更多
基金Joint Seismological Science Foundation of China (A07046).
文摘The basis for the NEHRP site coefficients is summarized in the paper. The comparison of site classification between China and US code provisions has been carried out. The relationship between two site classifications has been found by the analysis of wave velocity of site soil. Thus amplitude-dependent site amplification factors for China site classification has been gained by transformation from US amplification factors. Two amplification factors are specified： Fa for short periods and Fv for longer periods. On the contrast, there is only one long period factor and not a short period factor in the current China code provision.
基金Natural Sciences and Engineering Research Council of Canada (NSERC)University Network of Excellence in Nuclear Engineering (UNENE)
文摘Newmark design spectra have been implemented in many building codes, especially in building codes for critical structures. Previous studies show that Newmark design spectra exhibit lower amplitudes at high frequencies and larger amplitudes at low frequencies in comparison with spectra developed by statistical methods. To resolve this problem, this study considers three suites of ground motions recorded at three types of sites. Using these ground motions, influences of the shear-wave velocity, earthquake magnitudes, source-to-site distances on the ratios of ground motion parameters are studied, and spectrum amplification factors are statistically calculated. Spectral bounds for combinations of three site categories and two cases of earthquake magnitudes are estimated. Site design spectrum coefficients for the three site categories considering earthquake magnitudes are established. The problems of Newmark design spectra could be resolved by using the site design spectrum coefficients to modify the spectral values of Newmark design spectra in the acceleration sensitive, velocity sensitive, and displacement sensitive regions.
基金supported by the International Science and Technology Cooperation Program of China(Grant No.2008DFA21540)the National Hi-Tech Research and Development Program of China(Grant No.2006AA12Z113)+1 种基金the Chinese Defense Advance Research Program of Science and Technologythe Young Talents Filed Special Project of Institute of Remote Sensing and Application of Chinese Academy of Sciences
文摘Calibration coefficients validation is the foundation for ascertaining the sensor performance and carrying out the quantitative application.Based on the analysis of the differences between the calibration and validation,two calibration coefficients validation methods were introduced in this paper.Taking the HJ-1A satellite CCD1 camera as an example,the uncertainties of calibration coefficients validation were analyzed.The calibration coefficients validation errors were simulated based on the measured data at an Inner Mongolia test site.The result showed that in the large view angle,the ground directional reflectance variation and the atmospheric path variation were the main error sources in calibration coefficients validation.The ground directional reflectance correction and atmospheric observation angle normalization should be carried out to improve the validation accuracy of calibration coefficients.
