Collapse of Silver Bridge
Open University video (~25 min)
When the Silver Bridge collapsed during the rush hour, at just after 5 pm, on 15 Dec 1967, it had stood for 39 years before failing catastrophically in almost just an instant. It took 46 people down to their deaths.
Since 1928 it had bridged the Ohio River between Point Pleasant, West Virginia, and Kanauga, Ohio. The Silver Bridge was constructed with a novel form of suspension. Instead of the customary wire cables, the deck was supported from a chain of long, linked eye-bars, somewhat resembling the essential form of an elongated bicyle chain.
The disaster immediately posed the question “Why?” In the following months, pieces of the bridge were retrieved from the river’s fast-flowing water. A failure of one the eyes in the dogbone-shaped eye-bars was discovered. To which the question, “Why?” was asked again.
This documentary video provides an engineering analysis. After historical footage introducing the origins of the bridge, this instructive video discusses the suspected four factors which acted together on the cold December day, with a heavy traffic load, a suspension chain with no redundancy in the design, and a sudden failure at a stress crack.
The dramatic loss of life spurred a federal bridge safety inspection program.
See also the transcript of this video (pdf).