Testing a Retrofit Concept to Prevent Progessive Collapse

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

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.