A single-room,single-storey full-scale brick masonry building with precast RC roofing system was tested thrice under displacement controlled lateral cyclic loading,to assess the effectiveness of the basic repair and s...A single-room,single-storey full-scale brick masonry building with precast RC roofing system was tested thrice under displacement controlled lateral cyclic loading,to assess the effectiveness of the basic repair and seismic strengthening techniques.Initially,the virgin building specimen was loaded laterally to f^tilure.In the second stage,the damaged building was repaired by stitching across the cracks,and tested under the same lateral loading.In the third stage,the twice-damaged structure was repaired once more by stitching and strengthened by twin lintel belt in steel and vertical comer reinforcement, and re-tested.The building strengthened by twin lintel belt in steel showed about 28% higher strength under lateral loading than the virgin building.展开更多
By systematically studying seismic strengthening areas before 85 earthquakes with M>=6.0 in China, some results have been extracted. 1) Earthquake active strengthening area exists universally before strong shock o...By systematically studying seismic strengthening areas before 85 earthquakes with M>=6.0 in China, some results have been extracted. 1) Earthquake active strengthening area exists universally before strong shock or great earthquake; 2) The size of the strengthening area and its appearing time will increase when the earthquake magnitude increases; 3) The rate between the size of seismic strengthening area and the size of the source region decreases when earthquake magnitude increases; 4) The appearing time of the earthquake active strengthening region in the eastern part of China is longer than that in the western part of China. The above characteristics have been preliminarily explained qualitatively and half-quantitatively by applying the strong body earthquake generating model and the hard inclusion theory. Then applying the seismic strengthening area, we have obtained long-term predictions of 2 earthquakes, so the seismic strengthening area before strong earthquake or great earthquakes is a universal phenomenon, which has some mechanical base.展开更多
On May 5, 2008, China experienced a devastating earthquake, also known as Wenchuan earth-quake. Many buildings, whose seismic design levels were too low to endure a strong earthquake, were severely damaged or even des...On May 5, 2008, China experienced a devastating earthquake, also known as Wenchuan earth-quake. Many buildings, whose seismic design levels were too low to endure a strong earthquake, were severely damaged or even destroyed in the disaster.展开更多
The 285.5 m-high Xiluodu Arch Dam is located in a seismic region along the Jinsha River in China, where the horizontal components of peak ground accelerations for design and checking earthquakes have been estimated to...The 285.5 m-high Xiluodu Arch Dam is located in a seismic region along the Jinsha River in China, where the horizontal components of peak ground accelerations for design and checking earthquakes have been estimated to be 0.355 g and 0.423 g, respectively( g is the gravitational acceleration). The ground motion parameters of design and checking earthquakes are defined by exceedance probabilities of 2% over 100 years and 1% over 100 years, respectively. The dam shape was first selected and optimized through static analysis of the basic load combinations, and then adjusted after taking into account the seismic loads. The dam should be operational during and after the design earthquake with or without minor repairs, and maintain local and global stabilities during an extreme earthquake. Both linear elastic dynamic analysis and nonlinear dynamic analysis considering radiation damping, contraction joints, and material nonlinearity were conducted to assess the stress in the arch dam.The dynamic analysis shows that the maximum dynamic compressive stresses are less than the allowable levels, while the area with tensile stress over the limit is less than 15% of the dam surface and the maximum contraction openings range from 10 mm to 25 mm. The arch dam has sufficient earthquake-resistance capacity and meets the safety requirements. Nevertheless, steel reinforcement has been provided at the dam toe and in the zones of high tensile stress on the dam surface out of extra precaution.展开更多
Two great earthquakes of MS8.5 and MS8.3 determined by the China Earthquake Networks Center (CENC) occurred successively on September 12 and 13, 2007 in the sea area to the south of Sumatra, which is another group of ...Two great earthquakes of MS8.5 and MS8.3 determined by the China Earthquake Networks Center (CENC) occurred successively on September 12 and 13, 2007 in the sea area to the south of Sumatra, which is another group of large earthquakes after MS8.7 event on December 26, 2004 and MS8.5 event on March 29, 2005. The展开更多
文摘A single-room,single-storey full-scale brick masonry building with precast RC roofing system was tested thrice under displacement controlled lateral cyclic loading,to assess the effectiveness of the basic repair and seismic strengthening techniques.Initially,the virgin building specimen was loaded laterally to f^tilure.In the second stage,the damaged building was repaired by stitching across the cracks,and tested under the same lateral loading.In the third stage,the twice-damaged structure was repaired once more by stitching and strengthened by twin lintel belt in steel and vertical comer reinforcement, and re-tested.The building strengthened by twin lintel belt in steel showed about 28% higher strength under lateral loading than the virgin building.
文摘By systematically studying seismic strengthening areas before 85 earthquakes with M>=6.0 in China, some results have been extracted. 1) Earthquake active strengthening area exists universally before strong shock or great earthquake; 2) The size of the strengthening area and its appearing time will increase when the earthquake magnitude increases; 3) The rate between the size of seismic strengthening area and the size of the source region decreases when earthquake magnitude increases; 4) The appearing time of the earthquake active strengthening region in the eastern part of China is longer than that in the western part of China. The above characteristics have been preliminarily explained qualitatively and half-quantitatively by applying the strong body earthquake generating model and the hard inclusion theory. Then applying the seismic strengthening area, we have obtained long-term predictions of 2 earthquakes, so the seismic strengthening area before strong earthquake or great earthquakes is a universal phenomenon, which has some mechanical base.
文摘On May 5, 2008, China experienced a devastating earthquake, also known as Wenchuan earth-quake. Many buildings, whose seismic design levels were too low to endure a strong earthquake, were severely damaged or even destroyed in the disaster.
基金supported by the Program of Study on the Standard of Overall Safety Control of High Arch Dam of PowerChina Co.,Ltd.(Grant No.DJ-ZDXM-2014-19)
文摘The 285.5 m-high Xiluodu Arch Dam is located in a seismic region along the Jinsha River in China, where the horizontal components of peak ground accelerations for design and checking earthquakes have been estimated to be 0.355 g and 0.423 g, respectively( g is the gravitational acceleration). The ground motion parameters of design and checking earthquakes are defined by exceedance probabilities of 2% over 100 years and 1% over 100 years, respectively. The dam shape was first selected and optimized through static analysis of the basic load combinations, and then adjusted after taking into account the seismic loads. The dam should be operational during and after the design earthquake with or without minor repairs, and maintain local and global stabilities during an extreme earthquake. Both linear elastic dynamic analysis and nonlinear dynamic analysis considering radiation damping, contraction joints, and material nonlinearity were conducted to assess the stress in the arch dam.The dynamic analysis shows that the maximum dynamic compressive stresses are less than the allowable levels, while the area with tensile stress over the limit is less than 15% of the dam surface and the maximum contraction openings range from 10 mm to 25 mm. The arch dam has sufficient earthquake-resistance capacity and meets the safety requirements. Nevertheless, steel reinforcement has been provided at the dam toe and in the zones of high tensile stress on the dam surface out of extra precaution.
基金Foundation item: Joint Seismological Science Foundation of China (605033 and 106078)Contribution No.08FE3005, Institute of Geophysics, China Earthquake Administration
文摘Two great earthquakes of MS8.5 and MS8.3 determined by the China Earthquake Networks Center (CENC) occurred successively on September 12 and 13, 2007 in the sea area to the south of Sumatra, which is another group of large earthquakes after MS8.7 event on December 26, 2004 and MS8.5 event on March 29, 2005. The
