纽约世贸中心坍塌评析

Detailed Analysis of the Collapse of New York World Trade Center

“91 1事件”中纽约世贸中心所受到的作用包括飞机撞击、汽油燃烧、楼板超载等极为偶然的荷载 .整体破坏历经 1～ 2 h,属延性破坏 .估算了飞机对塔楼的撞击力 ,使塔楼产生了较大的位移 ,飞机的撞击切割了外筒的钢柱 ,破坏了楼板 .飞机的重量使楼板超载 ,引起“多米诺骨牌”式的塌落 ,最后由于钢柱长细比的大幅增大发生失稳破坏 ,使塔楼呈垂直坍塌 .汽油燃烧并非坍塌的主要原因 ,但引起材料强度和承载力的下降 。

In '911 incident' New York World Trade Center experienced some random loadings which include the ram of the planes, the burning of the gasoline as well as the overload of the floorslab. The process of the whole damage lasted 1~2 hours and it's a ductility damage. The ram force of the planes is analysed, which caused a great displacement of the tower, sheared the steel columns of the external tube and brought damage to the floorslab. The weight of the plane greatly overloaded the destroyed floorslab and caused a collapse in a 'dominoes' style'. The tower finally collapsed vertically when the steel columns lost stable equilibrium, due to the enormously increasing ratio of the length and slenderness. Though the burning of the gasoline was not the main cause for the collapse, it was resulted in a decrease of the strength of the materials and the load carrying ability, which aggravated the damage.