Testing a Retrofit Concept to Prevent Progessive Collapse

在地震和爆炸等极端事件中，建筑结构的一个关键元素，如柱子，很可能会倒塌。当建筑物中的一根柱子倒塌时，这根柱子上方的柱子不再被支撑，可能会倒塌，导致上面所有楼层的灾难性和“渐进式倒塌”。这种渐进式倒塌可能会导致许多人悲惨地丧生，比如1995年俄克拉荷马城的默拉大楼悲剧。为了避免这样的悲剧，结构应该有这样的机制，即失去一根柱子不会导致上面的柱子或结构的一大部分逐渐倒塌，从而产生多米诺骨牌效应。阿斯塔内博士刚刚完成了一种基于钢索的机制的成功测试，该机制可以防止这种渐进性坍塌。在该系统中，钢索被放置在楼板内，当柱子被移除时，钢索以类似于悬索桥缆索的“悬链线”作用，防止楼板倒塌和结构的逐渐倒塌。刚刚完成的测试是为新建筑进行的，在那里可以将钢缆放置在楼板内。鉴于这个系统在防止新建筑物倒塌方面取得成功，我们建议测试该系统，作为对现有脆弱建筑物进行翻新的一项措施。幸运的是，我们拥有刚刚完成的测试中的样本，处于轻微损坏的状态，并计划再次使用该样本进行拟议的探索性研究。这项探索性研究小额拨款的主要目标是将现有的一层60英尺乘20英尺的建筑样本，并在其上添加基于缆索的系统(在现有楼板下)作为翻新措施，并探索该系统在防止现有建筑结构逐步倒塌方面的潜力。

During extreme events such as earthquakes and explosions, it is quite possible that a critical element of a building structure, such as a column, collapses. When a column in a building collapses the columns above this column, not being supported anymore, can collapse resulting in a catastrophic and "progressive collapse" of all floors above. Such a progressive collapse can result in tragic loss of many lives such as the 1995 Murrah Building tragedy in Oklahoma City. In order to avoid such tragedies, the structure should have mechanisms that loss of one column does not result in a "domino" effect and progressive collapse of columns above or a large portion of the structure. Dr. Astaneh has just completed successful testing of a steel cable-based mechanism to prevent such progressive collapses. In the system, steel cables are placed inside the floor slabs and when a column is removed, the cables act in a "catenary" action similar to a suspension bridge cable and prevent collapse of the floor and progressive collapse of the structure. The tests just completed have been for new construction where it is possible to place the steel cables inside the floor slabs. Realizing the success of this system in preventing collapse of new buildings, we are proposing to test the system as a measure of retrofit for existing vulnerable buildings. Fortunately, we have the specimen from the just completed tests in a state of minor damage and plan to use the specimen one more time for this proposed exploratory investigation.The main objective of this Small Grant for Exploratory Research is to take the existing specimen which is a one story 60ft by 20 feet building and add the cable-based system to it (under the existing slab) as a measure of retrofit and explore potential of this system in preventing progressive collapse of the existing building structures.