In order to study the differences in vertical component between onshore and offshore motions,the vertical-to-horizontal peak ground acceleration ratio(V/H PGA ratio) and vertical-to-horizontal response spectral ratio(...In order to study the differences in vertical component between onshore and offshore motions,the vertical-to-horizontal peak ground acceleration ratio(V/H PGA ratio) and vertical-to-horizontal response spectral ratio(V/H) were investigated using the ground motion recordings from the K-NET network and the seafloor earthquake measuring system(SEMS).The results indicate that the vertical component of offshore motions is lower than that of onshore motions.The V/H PGA ratio of acceleration time histories at offshore stations is about 50%of the ratio at onshore stations.The V/H for offshore ground motions is lower than that for onshore motions,especially for periods less than 0.8 s.Furthermore,based on the results in statistical analysis for offshore recordings in the K-NET,the simplified V/H design equations for offshore motions in minor and moderate earthquakes are proposed for seismic analysis of offshore structures.展开更多
A wide variety of near-fault strong ground motion records were collected from various tectonic environments worldwide and were used to study the peak value ratio and response spectrum ratio of the vertical to horizont...A wide variety of near-fault strong ground motion records were collected from various tectonic environments worldwide and were used to study the peak value ratio and response spectrum ratio of the vertical to horizontal component of ground motion, focusing on the effect of earthquake magnitude, site conditions, pulse duration, and statistical component. The results show that both the peak value ratio and response spectrum ratio are larger than the 2/3 value prescribed in existing seismic codes, and the relationship between the vertical and horizontal ground motions is comparatively intricate. In addition, the effect of the near-fault ground motions on bridge performance is analyzed, considering both the material nonlinear characteristics and the P-A effect.展开更多
The variation of ground motion with depth is investigated in this paper, which is essential in determining the seismic design ground motion for embedded structures and pipelines. Firstly the earthquake ground motion o...The variation of ground motion with depth is investigated in this paper, which is essential in determining the seismic design ground motion for embedded structures and pipelines. Firstly the earthquake ground motion on surface and in subsoil recorded by Hosokura Mine array of Japan and six California Strong Motion Instrumentation Program geotechnical arrays of the United States from about fifty moderate and strong earthquakes are described. Then the arrays were classified into three different categories according to their site conditions. Finally the variation law of ground and sub-ground motion with depth is established as a result of a nonlinear regression analysis of the above-mentioned data. Through comparing the features in different sites, it is concluded that, in general, the amplitude (acceleration, velocity and displacement) of ground motion are decreasing with depth and the attenuation rate is higher in the shallow strata than that in deeper ones.展开更多
基金Project(2011CB013605)supported by the National Basic Research Development Program of China(973 Program)Projects(51178071,51008041)supported by the National Natural Science Foundation of ChinaProject(NCET-12-0751)supported by the New Century Excellent Talents Program in University of Ministry of Education of China
文摘In order to study the differences in vertical component between onshore and offshore motions,the vertical-to-horizontal peak ground acceleration ratio(V/H PGA ratio) and vertical-to-horizontal response spectral ratio(V/H) were investigated using the ground motion recordings from the K-NET network and the seafloor earthquake measuring system(SEMS).The results indicate that the vertical component of offshore motions is lower than that of onshore motions.The V/H PGA ratio of acceleration time histories at offshore stations is about 50%of the ratio at onshore stations.The V/H for offshore ground motions is lower than that for onshore motions,especially for periods less than 0.8 s.Furthermore,based on the results in statistical analysis for offshore recordings in the K-NET,the simplified V/H design equations for offshore motions in minor and moderate earthquakes are proposed for seismic analysis of offshore structures.
基金National Natural Science Foundation of China Under Grant No.50278002Dalian Nationalities University PHD Foundation Under Grant No.20066104
文摘A wide variety of near-fault strong ground motion records were collected from various tectonic environments worldwide and were used to study the peak value ratio and response spectrum ratio of the vertical to horizontal component of ground motion, focusing on the effect of earthquake magnitude, site conditions, pulse duration, and statistical component. The results show that both the peak value ratio and response spectrum ratio are larger than the 2/3 value prescribed in existing seismic codes, and the relationship between the vertical and horizontal ground motions is comparatively intricate. In addition, the effect of the near-fault ground motions on bridge performance is analyzed, considering both the material nonlinear characteristics and the P-A effect.
基金Natural Science Foundationof Heilongjiang Province (E0221).
文摘The variation of ground motion with depth is investigated in this paper, which is essential in determining the seismic design ground motion for embedded structures and pipelines. Firstly the earthquake ground motion on surface and in subsoil recorded by Hosokura Mine array of Japan and six California Strong Motion Instrumentation Program geotechnical arrays of the United States from about fifty moderate and strong earthquakes are described. Then the arrays were classified into three different categories according to their site conditions. Finally the variation law of ground and sub-ground motion with depth is established as a result of a nonlinear regression analysis of the above-mentioned data. Through comparing the features in different sites, it is concluded that, in general, the amplitude (acceleration, velocity and displacement) of ground motion are decreasing with depth and the attenuation rate is higher in the shallow strata than that in deeper ones.
