How did the 40-story tall building with frame structure collapse in the earthquake of magnitude 7 and 5?

Skyscraper, also known as super high-rise building, is a very high multi-storey building. Originally a building with 10 to 20 floors, now it usually refers to a high-rise building with more than 40 to 50 floors. With the development of high-rise buildings in different places, people's understanding of the definition height of skyscrapers is slightly different. In Chinese mainland, the building code stipulates that the height above 100 meters belongs to super high-rise buildings; Japan and France, which are over 60 meters, belong to super high-rise buildings; In the United States, buildings over 152 meters (500 feet) are generally considered as skyscrapers. 1 1 Century Central Building was built with only four floors, which was a rare high-rise building at that time. The walls of the tower are made of stone, and each floor should be able to bear the weight of each floor above. In order to make the tower stand, the wall at the bottom must be 5.2 meters thick. Buildings with load-bearing walls are up to 5 stories high. Because no matter how thick the bottom wall is, it can't support a higher structure. Only by using the frame to support the upper weight, coupled with the light wall to resist wind, frost, rain and snow, can a high-rise building be built. Medieval wooden houses were the first step in this direction. /kloc-in the 0/9th century, the output of steel increased greatly and its performance was reliable, and the fundamental solution was found. The first load-bearing building with integral iron frame was a four-story houseboat built in Gines, England in 1860. Height16m, cast iron column, wrought iron beam, span 9m, bolted. But skyscrapers are made in America. The first skyscraper with load-bearing frame is the 1884- 1885 Insurance Company Building in Chicago, which was designed by Jenny. The iron columns connected together in the lower six floors are wrought iron beam frames, and the upper four floors are steel frames. Since then, the United States has built steel-framed skyscrapers. As long as the frame is installed, all curtain walls of the whole skyscraper can be constructed separately on each floor at the same time, so the construction progress is very fast. Woolworths Building, a 55-story Gothic building in new york, took three years to build, with a height of 230 meters. 19 13 was the tallest building in the world when it was completed. The Empire State Building in New York was completed several months later than the Woolworth Building, and the construction period was only 15 months. * * * The building is 102 floor and 375 meters high, which is a symbol of the rapid development of building technology in the 20th century. Sears Tower in Chicago, 1 10 floor, 473 meters high, was completed in 1973. At present, there are1.20 thousand people working in it, and the total floor area of each floor is 4 1.4 hectares, which is 100 times the floor area of the bottom floor. The world's tallest skyscraper ranks the city with Chinese name and English name 1 BurjDubai700m Dubai 2 Taipei 1 0/Building Taipei1Building 508m1KLOC-0/Taipei 3 World Trade Center. Centre490m 1 18 Hong Kong 4 Petronas Malaysia1452m88mKuala Lumpur 4 Petronas Malaysia 2452m88mKuala Lumpur 5 Sears Tower 442m10 Chicago 6 Jinmao Tower 421m. 88 Shanghai 7 International Finance Center Phase II International Finance Center 420m 90 Hong Kong 8 Citi Plaza 391M80 China Guangzhou 9 Xinxing Plaza (Wang Di Building) Shunxing Plaza 384m69 Shenzhen 10 Empire State Building 38 1m 102 new york1/Kloc-. Central Plaza 374m 78 Hong Kong12 Bank of China Na Tower 367m7838+03 EmiratesOfficeTower355m54 Dubai 14 Tuntex & Kaohsiung Building 85; Jiantai Building 348m85 Kaohsiung 15 Aon Center 346m83 Chicago 16 Central Center 346m73 Hong Kong 17 John Hankao Center 343m 100 Chicago 18 Liu Jing Hotel Liu Yonghao. Tel330m 105 Pyongyang19 Burj Alarab32 1 m60 Dubai 20 Chrysler Building ChryslerBuilding3 19m77 new york 21Bank of America Plaza Bank of America 3 12m55 Atlanta 22 Bank of America Building USB. Ank Tower 31073 23menara Telekom310m55 Kuala Lumpur 24 Emirateshoteltower 309 M56 Dubai 25 AT & amp； TCorporateCenter307m60 Chicago 26JP JPMorgan Chase 305m75 Houston 27 Rainbow Center Phase II BaiyokeTowerII304m85 Bangkok 28 Shen Xing Plaza Building 2 TwoPrudentialPlaza303m64 Kingdom Center 3, Chicago 29 02m 4 1 Riyadh 30 First Canada Plaza FirstCanadianPlace298m72 Toronto 365438+Yokohamalandmarktower 296m70 296m70 Yokohama 32 Wells Fargo Plaza 5438+0 Southwake Drive 311 South wake drive 293 m65 Chicago 34 Seg Square 292m70 Shenzhen 35 American International 290m66 Building 290m66 new york 36KeyTowerKeyTower289m57 Cleveland 37. Plaza 66288m66 OneLibertyPlace288m6 1 Philadelphia 39 BankofAmericaPlaza285m76 Seattle 40 Tomorrow Plaza 285m55 Shanghai 4 1 Changjiang Group Center Qinggong Hole. Ntre283m62 Hong Kong 42 Trump Tower the Trump Building 283m70 new york 43 Bank of America Plaza 281M 70 Dallas 44 Hualian Bank Building OUBCentre280m63 Singapore 45*** And Gonghe Square Plaza280m66 Singapore 46 UOBPlazaOne280m66 Singapore 47 CitigroupCenter279m59 new york 48 Hong Kong New World Center Hong Kong New World Building 278m6 1 Shanghai 49 scotiaplaza.