Based on the site historical earthquake data,a method of seismic risk analysis is presented.Once the frequency of earthquake response intensity and the relative value showed a logarithmic linear,the maximum similarity...Based on the site historical earthquake data,a method of seismic risk analysis is presented.Once the frequency of earthquake response intensity and the relative value showed a logarithmic linear,the maximum similarity method would be used to obtain β,λ,and Imax,and also achieve the results of risk analysis on each site.At the same time,the "logic tree" method can be used to calibrate the uncertainty of the risk on each site.Then the final results of risk analysis indicate that this method is feasible,particularly for the sites showing intensity anomaly.展开更多
Based on the existing research, this paper presents an innovative methodology to realize direct damage-based seismic design for RC frame structures by mobilizing ESDOF theory and the damage-based strength reduction fa...Based on the existing research, this paper presents an innovative methodology to realize direct damage-based seismic design for RC frame structures by mobilizing ESDOF theory and the damage-based strength reduction factor（RD factor）. A design example is then followed to verify this method.展开更多
Ground motion records are often used to develop ground motion prediction equations （GMPEs） for a randomly oriented horizontal component, and to assess the principal directions of ground motions based on the Arias in...Ground motion records are often used to develop ground motion prediction equations （GMPEs） for a randomly oriented horizontal component, and to assess the principal directions of ground motions based on the Arias intensity tensor or the orientation of the major response axis. The former is needed for seismic hazard assessment, whereas the latter can be important for assessing structural responses under multi-directional excitations. However, a comprehensive investigation of the pseudo-spectral acceleration （PSA） and of GMPEs conditioned on different axes is currently lacking. This study investigates the principal directions of strong ground motions and their relation to the orientation of the major response axis, statistics of the PSA along the principal directions on the horizontal plane, and correlation of the PSA along the principal directions on the horizontal plane. For these, three sets of strong ground motion records, including intraplate California earthquakes, inslab Mexican earthquakes, and interface Mexican earthquakes, are used. The results indicate that one of the principal directions could be considered as quasi-vertical. By focusing on seismic excitations on the horizontal plane, the statistics of the angles between the major response axis and the major principal axis are obtained; GMPEs along the principal axes are provided and compared with those obtained for a randomly oriented horizontal component; and statistical analysis of residuals associated with GMPEs along the principal directions is carried out.展开更多
This paper addresses a unified approach of the PID controller design for low as well as high order unstable processes with time delay.The design method is based on the direct synthesis(DS)approach to achieve the enhan...This paper addresses a unified approach of the PID controller design for low as well as high order unstable processes with time delay.The design method is based on the direct synthesis(DS)approach to achieve the enhanced load disturbance rejection.To improve the servo response,a two-degree of freedom control scheme has been considered.A suitable guideline has been provided to select the desired reference model in the DS scheme.The direct synthesis controller has been approximated to the PID controller using the frequency response matching method.A consistently better performance has been obtained in comparison with the recently reported methods.展开更多
强震中下软上硬坡体同震崩塌发育,为了揭示这类坡体地震动的响应特征,在珙县五同村安置了强震监测仪,对斜坡表面和不同岩性的地震动响应进行监测,并记录到不同方位、不同震中距的2次地震。研究表明:①地震动响应规律有极强的方向性和距...强震中下软上硬坡体同震崩塌发育,为了揭示这类坡体地震动的响应特征,在珙县五同村安置了强震监测仪,对斜坡表面和不同岩性的地震动响应进行监测,并记录到不同方位、不同震中距的2次地震。研究表明:①地震动响应规律有极强的方向性和距离性。2次地震相距监测站台的方向和距离不同,使M s 4.0级地震的峰值加速度和阿里亚斯强度反而比M s 3.2级地震小。②0~30 Hz的地震波在低地山岭的高陡临空面附近有放大效应。1^(#)监测点的主频小于3^(#)与5^(#)监测点,3^(#)监测点的主频最高。5^(#)点的幅值范围为0.018~0.055 m/s^(-2),3^(#)点幅值范围为0.036~0.087 m/s^(-2),3^(#)点相较于5^(#)点,其三向最高幅值同比放大了1.58~2.0倍。③泥质砂岩的主频为4.8~8.4 Hz,灰岩的主频为5.5~21.4 Hz,不同的岩层共振频率不同,灰岩对地震波的选频放大效应强于泥质砂岩。④地震波在不同高程的山岭斜坡部位具有选择放大作用,在一定范围内高程越大地形放大效应越明显。展开更多
文摘Based on the site historical earthquake data,a method of seismic risk analysis is presented.Once the frequency of earthquake response intensity and the relative value showed a logarithmic linear,the maximum similarity method would be used to obtain β,λ,and Imax,and also achieve the results of risk analysis on each site.At the same time,the "logic tree" method can be used to calibrate the uncertainty of the risk on each site.Then the final results of risk analysis indicate that this method is feasible,particularly for the sites showing intensity anomaly.
文摘Based on the existing research, this paper presents an innovative methodology to realize direct damage-based seismic design for RC frame structures by mobilizing ESDOF theory and the damage-based strength reduction factor（RD factor）. A design example is then followed to verify this method.
基金Natural Science and Engineering Research Council of Canada(NSERC)
文摘Ground motion records are often used to develop ground motion prediction equations （GMPEs） for a randomly oriented horizontal component, and to assess the principal directions of ground motions based on the Arias intensity tensor or the orientation of the major response axis. The former is needed for seismic hazard assessment, whereas the latter can be important for assessing structural responses under multi-directional excitations. However, a comprehensive investigation of the pseudo-spectral acceleration （PSA） and of GMPEs conditioned on different axes is currently lacking. This study investigates the principal directions of strong ground motions and their relation to the orientation of the major response axis, statistics of the PSA along the principal directions on the horizontal plane, and correlation of the PSA along the principal directions on the horizontal plane. For these, three sets of strong ground motion records, including intraplate California earthquakes, inslab Mexican earthquakes, and interface Mexican earthquakes, are used. The results indicate that one of the principal directions could be considered as quasi-vertical. By focusing on seismic excitations on the horizontal plane, the statistics of the angles between the major response axis and the major principal axis are obtained; GMPEs along the principal axes are provided and compared with those obtained for a randomly oriented horizontal component; and statistical analysis of residuals associated with GMPEs along the principal directions is carried out.
文摘This paper addresses a unified approach of the PID controller design for low as well as high order unstable processes with time delay.The design method is based on the direct synthesis(DS)approach to achieve the enhanced load disturbance rejection.To improve the servo response,a two-degree of freedom control scheme has been considered.A suitable guideline has been provided to select the desired reference model in the DS scheme.The direct synthesis controller has been approximated to the PID controller using the frequency response matching method.A consistently better performance has been obtained in comparison with the recently reported methods.
文摘强震中下软上硬坡体同震崩塌发育,为了揭示这类坡体地震动的响应特征,在珙县五同村安置了强震监测仪,对斜坡表面和不同岩性的地震动响应进行监测,并记录到不同方位、不同震中距的2次地震。研究表明:①地震动响应规律有极强的方向性和距离性。2次地震相距监测站台的方向和距离不同,使M s 4.0级地震的峰值加速度和阿里亚斯强度反而比M s 3.2级地震小。②0~30 Hz的地震波在低地山岭的高陡临空面附近有放大效应。1^(#)监测点的主频小于3^(#)与5^(#)监测点,3^(#)监测点的主频最高。5^(#)点的幅值范围为0.018~0.055 m/s^(-2),3^(#)点幅值范围为0.036~0.087 m/s^(-2),3^(#)点相较于5^(#)点,其三向最高幅值同比放大了1.58~2.0倍。③泥质砂岩的主频为4.8~8.4 Hz,灰岩的主频为5.5~21.4 Hz,不同的岩层共振频率不同,灰岩对地震波的选频放大效应强于泥质砂岩。④地震波在不同高程的山岭斜坡部位具有选择放大作用,在一定范围内高程越大地形放大效应越明显。
