“9·11”后为防撞防火改设计国贸3期的规划经过多次修改,美国“9·11”事件发生后还专门改了一次,以加强楼体的防撞、防火性。据悉,当时飞机撞上世贸大楼,大楼很快就倒塌了。这是因为世贸大楼是钢结构的,在高温燃烧下钢很快就熔化了。国贸3期主梁采用一种名为“劲性柱”的结构并在主梁外包裹上钢筋混凝土,钢筋混凝土可以起到加固和隔热的作用,次梁则采用 After “9.11”, the plan for anti-collision fire protection design of China World Trade 3 has been revised several times. After the incident of “9.11” in the United States, the plan was changed once again to strengthen the anti-collision and fire prevention of buildings Sex. It is reported that when the plane hit the World Trade Center, the building collapsed soon. This is because the World Trade Center is made of steel and the steel melts quickly under high temperature combustion. Guomao Phase 3 main girder uses a structure called “strong column ” structure and the main beam wrapped in reinforced concrete, reinforced concrete can play the role of reinforcement and insulation, the second beam is used