A series on the failure of various bits of infrastructure, must include the failure that changed the way we inspect bridges. Silver Bridge Collapse.
UPDATE: The short documentary I included (8 minutes) has been deleted. The replacement isn’t an informative, so if you have time, view the longer video.
On December 15, 1967, the Silver Bridge collapsed while it was full of rush-hour traffic, resulting in the deaths of 46 people. Two of the victims were never found. Investigation of the wreckage pointed to the cause of the collapse being the failure of a single eyebar in a suspension chain, due to a small defect 0.1 inch (2.5 mm) deep. Analysis showed that the bridge was carrying much heavier loads than it had originally been designed for and was poorly maintained.
National Bridge Inspection Standards were a result of that collapse. Real inspections are supposed to be carried out at least every 2 years, and things should be (and usually are) addressed. Following the 1967 collapse many bridges were retrofitted or dismantled.
OK so this is also the bridge that gave rise (in part) to the Mothman stories. That is all I have to say about that. If you’re interested in that kind of thing, the links, sites, even a movie, are easy enough to find.
This first documentary is
8 minutes . Actually it is less than that because it starts to repeat. (You are not imagining it.) It covers the highlights of construction and how the failure was analyzed. It isn’t the greatest, but it is short (for those 21st Century attention spans). And yes, this documentary gets the date wrong. It was December 15th, not the 16th.
This second documentary, from the Open University, is complete, and well done, but the problem is that it’s 25 minutes long. It covers design, and how the design was not sufficient over time, as loads increased. It covers maintenance, and the lack thereof. It covers the complete lack of (reasonable) inspections. And it is complete if you have the time.