On Wed, 17 Oct 2001, Met History wrote:

> John, perhaps my original post was too sketchy.  First, I am curious about
> Mr. Robertson's statement (apparently made at a conference in Germany in 1993
> after the garage bombing at the Trade Center).  Surely he wasn't specifically
> thinking that 707's crash with empty fuel tanks.  And yet, fire being the
> enemy of steel, was there perhaps a "disconnect" in his thinking?  After all,
> he did volunteer the point about the 707 - no one else asked.
>
> It seems unlikely that Mr. Robertson, having raised the original point, would
> have been blind to the possibility of a resulting jet-fuel fire

Perhaps he was.  My guess is that he was speaking, not of the awful
practicalities of what happens when a jet actually crashes into a
building, but rather of the building's ability to withstand a physical
impact that large on one side and not collapse.  The building, even the
floors above the crash, did indeed withstand that blow.

> An alternate WTC emergency plan might have been "Fire caused by
> internal event - tenants stay put on floors; fire caused by 707 crash,
> tenants evacuate."  Since a large number of people -- 1000? 2000? --
> died because they were told to stay put (either by loudspeaker or by
> the existing emergency instructions), that seems significant.

Obviously you are closer to the facts on this than I am, but my
understanding is that the "stay put" or "return to your offices" message
was broadcast in the tower that (at that point) had not been hit.
Unexpectedly, that turned out to be grievously bad advice, and fortunately
thousands (perhaps remembering 1993) ignored it.

> Second, I don't have the expertise to say, as you may, that <<no building
> typology that could have withstood this attack>>.  But that is really not the
> only goal -- another  goal is simply to withstand the attack long enough for
> the everyone to get out.

That is precisely, as I understand it, the point of a lot of fire codes:
that the building should remain standing long enough for evacuation.  The
fact that the twin towers stood as long as they did under the
circumstances saved some 25,000 lives.  Greater awareness of the
likelihood of collapse might have saved more, admittedly.

> Would the older terra-cotta encasement method of steel have
> protected it longer, or shorter?  What about a reinforced concrete tower,
> like Petronas?  How about a similar tower designed on the 1920's era grid
> plan of steel columns, like the Empire State?

I'd like to know these answers, too, particularly the last one.  However,
I suspect that it would not have made economic or engineering sense to
build 110-story WTC towers in the 1960s using the same technology as
Empire State.

> For the WTC floor connections
> to the surrounding tube, is there an alternate method that might have "shed"
> the huge loads off to the sides, so that the top 20 floors would have fallen
> onto the street, instead of pancaked down?  Would that be better or worse?

My instinct is that this would have spread the devastation over a wider
area and killed more people, including many thousands of those who got out
of the towers.

> For that matter, what would happen if another airplane, even without malice
> aforethought, crashed into the Empire State -- what is the likely failure
> model there?  I suspect fire & ESB officials are now examining that very
> question, and not just to needle Mr. Robertson, who is probably feeling
> pretty rotten right now.

Y'all may have seen this: Mr. Robertson gave a lecture and slide show to a
structural engineers' group.  During most of his presentation, he was as
matter-of-fact as a coroner discussing an autopsy, but while he was
responding to questions, he broke down and wept.

                                  Larry

---
Lawrence Kestenbaum, [log in to unmask]
Washtenaw County Commissioner, 4th District
The Political Graveyard, http://politicalgraveyard.com
Mailing address: P.O. Box 2563, Ann Arbor MI 48106