1981年3月27日佛罗里达州可可滩一座五层分户出租公寓建筑倒塌成一片废墟,死七人,伤二十三人(图1、图2)。倒塌时正在浇灌屋面混凝土。从倒塌现场中看出3～4层高的柱子没有折断,这说明楼板是在板与柱子间的连接被切断后滑下的。从楼板的垂直推叠现状说明倒塌时未产生侧移。现场幸存者证实破坏是从五层楼板开始的。 On March 27, 1981, a five-storey apartment building for rent in Cocoa Beach, Florida, collapsed into a ruin, killing seven people and injuring twenty-three (Figures 1, 2). The concrete of the roof is being poured when it collapses. From the collapsed site, it was found that the pillars with 3 to 4 floors were not broken, indicating that the floor slab was sliding down after the connection between the slab and the pillar was cut off. The fact that the vertical push of the floor shows that there was no sideshift when it collapsed. The survivors at the scene confirmed that the damage started from a five-story floor.