Thanks. That's my understanding of the failure mode as well. The steel
didn't melt but became soft and warped and the concrete expanded and
caused extra deforming loads on the softened steel outer wall...
At 17:41 9/16/2001, Roger Gibbs was inspired to say:
>When Kaiser Steel was building ships during WWII, they moved to welded, rather
>than riveted construction. Competing ship yards claimed riveted contruction
>being more robust, with a slight ability to give before failure. The Kaiser
>Liberty ships and Aircraft Carriers (small ones) never failued (other than
>torpedoes) as far as I know.
>
>After the Northridge earthquake I listened to a lecture on the failure of
>welded
>joints in office buildings. The Northridge quake was a "thrust" rather than
>"slip" quake as I recall, but in any case the loads applied to the buildings
>(from the quake) were greater than the design loads ! Anyway, several
>buildings
>failed at weld joints and there were (are?) lawsuits aplenty. Suits
>againts the
>building desiners, welders, general contractors, even Lincoln welding company
>(who manufactured the weld rod used). But the end result was in increase in
>design loads in the building codes and a revised weld schedule.
>
>The WTC failed, as I understand it, because the heat inside was enough to make
>the steel melt, or at least become soft. This floor collapsed and the weight
>and inertia of the floors above it cause the whole bulding to come down.
>It was
>not caused by failure of the joints.
>
>-Roger
>
>Richard Beels wrote:
>
> > I read that the WTC buildings were welded rather than riveted. Anybody
> > here have knowledge and/or experience with structural building welding?
> >
> > What differences in the structural integrity of the towers would there be
> > if the towers were riveted in stead of being welded? I'm thinking that the
> > building couldn't have been built if it were riveted because of its design
> > - as opposed to the Empire State Building and all the concrete and
> > duplicate structure...
> >
> > Cheers!
Cheers!
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