On Thu, 02 Aug 2007 19:13:21 GMT, Reg > wrote:

>Dave Smith wrote:
>
>> maxine in ri wrote:
>>
>>>>I think this event will reveal some fundamental flaws in their
>>>>inspection regime. Whatever caused it, whether it's erosion
>>>>of the pylons (known as scouring, it has caused collapses
>>>>before. A major incident occurred in upstate NY) or deterioration
>>>>of the structure itself, it should have been caught by their normal
>>>>inspection regime.
>>>
>>>There were no pylons. The bridge had a 450 foot unsupported span with
>>>no suspension according to the report I heard.
>>
>> Of course is was supported, It has stood up since it opened in 1967. There
>> was no suspension because it was not a suspension bridge. It was a steel
>> arch Deck Truss bridge. Arches are supposed to be able to bear a lot of
>> weight. Pylon may or may not be an accurate word to describe the concrete
>> supports or pedestals, two on each side of the river, which support the
>> ands of the arched metal structure.
>
>"Footings" is probably the term I should have used.
>
>I think there's a reasonable chance one may have come down as a result
>of bridge scour, similar to the Schoharie Creek incident in 1987.
>This caused a progressive collapse.
>
>Another possible cause is structural failure due to metal fatigue.
>
>In any case, the design lacked sufficient redundancy to
>prevent a progressive collapse. One piece falls, causing them
>all to go down. Such older designs require stricter inspection
>and maintenance, which it appears didn't happen in this case.

on the contrary, it was inspected at least twice and found
'structurally deficient.' they just didn't fix it.

your pal,
blake