同济大学：《建筑结构抗震》课程教学资源（课件讲稿）Chapter 1 Earthquake and Ground motions（2/2）.pdf_大学文库

2015/9/22 2 7 Quiz 1. Magnitude and Intensity are all indexes which related to the earthquake power, True or False? 2. For a given Magnitude we can calculate the earthquake energy, True or False? 3. We can evaluate earthquake intensity by our feelings, building performances and land changing, True or False? 4. If an earthquake magnitude is determined, the intensity is determined too, True or False? 5. Why the earthquake happened, the people at epicenter who felt the vertical vibration earlier than horizontal vibration? True! False! 8 1.4 Seismicity in the world 熊海贝，同济大学土木工程学院 2015/9/22 xionghaibei@tongji.edu.cn 1.4.1 World-wide seismic activities Fig.1.4.1 Tectonic plate and world-wide distribution of earthquakes 9 熊海贝，同济大学土木工程学院 2015/9/22 xionghaibei@tongji.edu.cn http://earthquake.usgs.gov/earthquakes/world/seismicity_maps/world.pdf Seismic Zone 1. Circum-Pacific seismic zone, including the Pacific side of South American, Central America, and North America, the Aleutian （琉球群岛）Islands, the Kamchatka Peninsula (马来西亚半岛) , Japan, Indonesia, and New Zealand； 2. Eurasian seismic zone, stretching from southeast Asia through the Middle East to the Mediterranean Sea （地中海）. 3. Midoceanic ridge and the area where the ridge reveals itself on land 4. Parts of China, the Middle East, and other continents 10 熊海贝，同济大学土木工程学院 2015/9/22 xionghaibei@tongji.edu.cn 11 1.4.2 Seismic activities of China • Continental China is part of the Eurasian plate. • The Pacific and Philippine plate push against it from the east, while the Indo-Australian plate pushes from the south, producing a very complicated stress field. • Active faults of large size have been created, resulting in a number of in-plate earthquakes. • The distribution of earthquake epicenters in China suggests two significant seismic zones: north-to-south strip and west-to-east strip. 2015/9/22 熊海贝，同济大学土木工程学院 xionghaibei@tongji.edu.cn 11 12 1.4.2 Seismic activities of China 2015/9/22 熊海贝，同济大学土木工程学院 xionghaibei@tongji.edu.cn 12

2015/9/22 3 • The Pacific plate and the Philippine plate submerge along the Pacific Ocean side of the Japanese islands. Seismicity is therefore very high in the area between the islands and the ocean ridge. • Large earthquakes of magnitude greater than 8 tend to be located on the east side (sea area) of the islands. 1.4.3 Seismic activities of Japan 2015/9/22 熊海贝，同济大学土木工程学院 xionghaibei@tongji.edu.cn 13 • Along the shoreline of California there runs the San Andreas fault, where many earthquakes have occurred. • Earthquakes have also occurred in the north part of New York State and in Missouri as well as in California and Nevada. 1.4.4 Seismic activities of North and South America • Because the Cocos plate and the Nazca plate are submerging on the Pacific Ocean side of Central and South America respectively, this island-arclike area has high seismicity. • On the western side of the Pacific Ocean, the whole coast of Central and South America is agitated by many earthquakes. 2015/9/22 熊海贝，同济大学土木工程学院 xionghaibei@tongji.edu.cn 14 • In New Zealand seismicity in the eastern part of North Island and the southern part of South Island is as high as in southern California. • The Philippine suffered a large earthquake in 1976 with 4,000 people killed. 1.4.5 Seismic activities of South Pacific Area 2015/9/22 熊海贝，同济大学土木工程学院 xionghaibei@tongji.edu.cn 15 • In Europe, earthquake activity is quite widespread. • Countries in Europe with relatively high seismicity include Italy, Greece, Yugoslavia, Romania, Turkey,Spain, and Portugal. • Destructive earthquakes do occur from time to time in Germany, Austria, and Switzerland, and even in the North Sea region and Scandinavia. 1.4.6 Seismic activities of Europe http://earthquake.usgs.gov/earthquakes/recenteqsww/ 2015/9/22 熊海贝，同济大学土木工程学院 xionghaibei@tongji.edu.cn 16 • There have been relatively very few earthquakes in the Africa continent, with some exceptions in Morocco, Algeria, Tunisia, and Egypt. 1.4.7 Seismic activities of Africa 2015/9/22 熊海贝，同济大学土木工程学院 xionghaibei@tongji.edu.cn 17 1.4.9 Disasters caused by earthquakes Direct disaster • Damages to ground: cracks，liquefaction，landslide • Damages to buildings and infrastructures 5 grades Secondary disaster • Tsunami • Fire • Flood 2015/9/22 熊海贝，同济大学土木工程学院 xionghaibei@tongji.edu.cn 18

2015/9/22 6 Modified Seismic Zoning Map in Sichuan and Gansu (2008) 0.05 0.15 0.20 0.30 Intensity <Ⅵ Ⅵ Ⅶ Ⅷ ≥Ⅸ Total Area (104×km2 ) 201 361 320 68 9.5 959.5 Percentage (%) 21 38 33 7 1 100 Area of different intensity 74.5% 25.5% 74.5% Seismic region Non-seismic region 25.5% 660 cities 85.7% 14.3% 85.7% 14.3% Seismic region Non-seismic region 118 cities of over 1 million population Seismicity of cities in China Three-level Seismic Fortification objectives: The first level The second level The third level 1.5.1 Seismic fortification objectives Code for Seismic Design of Building Structures: TJ 11-78 GB 11-89 GB 50011-2001 GB 50011-2001 (modified version, 2008) GB 50011-2010 2015/9/22 熊海贝，同济大学土木工程学院 xionghaibei@tongji.edu.cn 33 1) The first level When buildings designed based on the code are subjected to the influence of frequently occurred earthquakes with an intensity of less than the fortification intensity of the region, they will not be, or will be only slightly damaged and will continue to be serviceable without repair. ------------- No damage under minor earthquake. 2) The second level When buildings are subjected to the influence of earthquakes equal to the fortification intensity of the region, they may be damaged but will still be serviceable after ordinary repair or without repair. ------ Repairable under moderate earthquake 2015/9/22 熊海贝，同济大学土木工程学院 xionghaibei@tongji.edu.cn 34 3) The third level When buildings are subjected to the influence of expected rare earthquakes with an intensity higher than the fortification intensity of the region, they will not collapse nor suffer damage that would endanger human lives. ------------- No collapse under major earthquake. 2015/9/22 熊海贝，同济大学土木工程学院 xionghaibei@tongji.edu.cn 35 1) The first level By the elastic analysis, the carrying capacity of the structure is checked under the fundamental combination of effects of seismic action of minor earthquake and other loads, and the elastic seismic deformation is checked under the action of minor earthquake. Calculation is necessary under the first level. 1.5.2 Seismic design method 2) The second level The objective of this level is realized mainly by seismic conceptual design and constructional measuresor detailing. 3) The third level The elasto-plastic deformation is checked under the action under rare earthquake