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To: MplsSteve

Exactly. Maybe in a few days.

It’s just so bizarre.


835 posted on 08/01/2007 6:07:06 PM PDT by SE Mom (Proud mom of an Iraq war combat vet -Fred'08)
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To: SE Mom

Here’s what the fellow on FOX is talking about:
http://en.wikipedia.org/wiki/Mianus_River_Bridge

The collapse was caused by the failure of two pin-and-hanger assemblies that held the deck in place on the outer side of the bridge. The hanger on the inside part of the expansion joint at the southeast corner was forced from the pin that was holding it, and the load was shifted to the only other pin in the joint. The problem was caused by rust formation within the bearing on the pin, exerting a tremendous force on the hanger. The extra load on the remaining pin started a fatigue crack at a sharp corner on the pin. It failed catastrophically and the deck was then supported at just three corners.

When two heavy trucks and a car entered the section, the remaining expansion joint failed and the deck crashed into the river below. The ensuing investigation cited corrosion from water buildup due to inadequate drainage as a cause. The highway drains had been deliberately blocked during roadmending some 10 years before, and water leaked down through the pin bearings, causing them to rust. The outer bearings were safety-critical and non-redundant, a design flaw of this particular type of structure. The bearings were difficult to inspect close-up, although traces of rust could be seen near the affected bearings


851 posted on 08/01/2007 6:08:49 PM PDT by SE Mom (Proud mom of an Iraq war combat vet -Fred'08)
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