Article 5682 of alt.engr.explosives:
From: dhartung@MCS.COM (Daniel A. Hartung)
Subject: Re: Lindheimer Observatory Demolition
Date: Sat, 16 Sep 95 06:33:35 GMT
Organization: Evanston Rotaract Club
ralentz@MCS.COM (Robert A. Lentz) wrote:
>Now, after receiving the grant and hiring an astronomer to oversee its
>implementation, Northwestern has decided to demolish the observatory instead.
>On the afternoon of Wednesday Septermber 13th, you can see what Northwestern
>thinks of education when they demolish the Lindheimer Observatory.
I think it's disappointing that they're doing this, but I can understand
their reasoning. NWU has always had a very Chicago "tear it down and
build anew" attitude, anyway, so it's unsurprising. (I think it was
a tad specious to try to abuse the historical landmark laws to designate
this 30-year-old structure, though.)
The building is a bit of a hero, though, proving a fiasco to demolish.
Over the past few days the following transpired:
* The explosives experts subcontracted by the demolition company
failed to make the structure collapse by blowing up key struts.
[It turned out that the superstructure is 8- and 10-inch pipes,
each a full one-inch gauge steel instead of 1/2 inch as originally
thought. I smell contract lawsuit....] A planned two-step
explosion of the superstructure and then the building was apparently
halted when the first round just tipped the whole structure
about ten degrees.
* The demolition company then contracted with a heavy-duty truck
towing company to drag the building down. Three 50-ton (or 30?)
winches Thursday morning resulted in the trucks mainly being
dragged or shimmied toward the building.
* Later that afternoon, after digged berms to hold the trucks in
place, they tried again. This resulted in a couple of snapped
one-inch steel cables, one falling on electrical wires which
then made a streetlamp explode spectacularly (I was told), and
no appreciable movement on the part of the building.
According to a Palatine fireman in the audience, related to
two of the tow-truck drivers and formerly one himself, the
cables in use were designed to snap out of their end-connections
before they would actually fail -- much safer, though not as
much as the synthetic ropes they normally use when winching
semis up out of ditches, which would sort of energetically fray
and twirl up in the air, dissipating most of their energy
before hitting any personnel nearby.
[Cables like this holding ships at dock fail from time to
time, and can cut a man in two; one once did so within breeze-
length of Princess Fergie.]
* A third attempt that evening took place after an arc welder was
used to "score" rings around the structural tubes, in order to
weaken them. This was an extremely hazardous job, and the
demolition company's president would let nobody else do it or
even be near the building while he worked. In the dark of
Thursday evening, we watched as periodic twenty-foot sprays
from the flame ignited the scene ... and eventually some
scrub brush nearby ... fortunately just as he was finishing up.
The towing then commenced, with the fire flaring up uncontrolled
(perhaps too dangerous then for firemen to approach?). There
was no movement, though, and the fire fortunately burned itself
out shortly afterward.
* In late evening, they moved the trucks around so that
the largest with a 100-ton winch was the only one in use.
With a huge creak, the structure groaned and a tube snapped --
the building then tipped slowly over another ten degrees,
and clunked audibly on the next level of tubing!
* As midnight approached, the owner again scored tubes, this
time on the side of the building. After some 20 minutes, he
suddenly dashed away, apparently having heard or sensed something;
but the building held. Another worker then dragged the arc
welder out by the gas hose. A small end-loader was then cabled
to this scored tube, revved its engines, and dashed forward about
twenty feet (with hurricane fencing another 10 feet ahead down the
hill!) -- but the cable snapped mightily and the tube held.
* The owner again took on a job nobody else should risk, and used
a huge diesel digger with a claw attachment to literally grab
pull and otherwise attack the superstructure, which though cut,
was resting on itself and not separating due to the force of
sheer weight. Eventually, with the diesel machine up on its
haunches so to speak, the front of its long treads clearly
airborne, he succeeded in pulling this tube apart.
But no movement from the building!
* At this point they closed shop for the night and the owner declared
that they would try again, perhaps with explosives, on Friday. The
bomb guys were coming up (ironically from Oklahoma) and would arrive
after noon Friday.
* Friday as I checked the site an oddly modified brown pickup with
OK plates was being closed up and driven away. Apparently, either
it was deemed too dangerous for another mining attempt, or too
unlikely for success.
* Friday night preparations were being made for cranes to get in
so that the whole structure could be cut up piece by piece.
The construction contract was for a fixed $250,000, so all these
delays and extra work cut into the demolition company's profit,
as well as resulting in extremely hazardous work conditions.
On hand for the demolition were several members of the astronomy
department, who all lamented its loss as a valuable educational
(though not research, due to light & air pollution) tool. Also
there was one of the engineers who had originally designed the
structure, including the unique 16-point star in the center of
each (dodecahedral?) structure element. (He also claimed this
was before the geodesic dome, which isn't quite true; it was
before the geodesic dome came into popular use.) He agreed with
my assessment that tipping the building over would simply
result in the structure retaining its integrity, with the
building on its side!
The superstructure was designed to protect the telescopes from
wind shear vibration here on the lakefront. The designer was
incensed that the university had later modified the building to
enclose the telescope towers and attach these walls to the
superstructure, as it would carry the vibration to the towers,
but a student reported that it didn't practically affect observations.
After the initial topple, the observatory tilted at 15 degrees,
the site became a minor media circus, with local newscasts using
it as a teaser during program lead-in (the inevitable name,
"The Leaning Tower of Evanston"). You could smell the disappointment
as news crews learned that there would be no spectacular footage
of a toppling or exploding building.
The telescopes were removed some time ago and sold to the Lowell
Observatory near Flagstaff, AZ.
The official justification for this action is that the observatory
was endowed to be a graduate facility, but due to deterioration of
viewing conditions as light-pollution and smog increased, it
became a strictly undergraduate "education" facility and not worth
the cost of rehab.
Overheard at the site:
"First Notre Dame, now this. This is turning into an exciting year."
"And classes haven't even started!"
"Why not use a cruise missile here instead of in Bosnia? What are
we paying taxes for?!" <mock rage>
"It's a landmark, a tragedy. What kind of people are running this
University????" <students pretending to be concerned for the
TV cameras, then breaking into laughter afterward>
"This is horrible, I love this building. It's a landmark every time
I drive into the city from Chicago [visible a couple of miles south].
I took a trip to Europe recently -- they *value* their old buildings
there. This is just another example of American lack of taste."
<Evanston resident, unaware that at 30 years old building is not
comparable to, say, the Louvre>
"At last we've got a tourist attration--the Leaning Tower of Evanston."
"Why not? Niles has one."
[Niles, IL, has a 1/4 size replica of the Pisa tower, intended as
a centerpiece for a civic park but now on the property of the YMCA.]
"Why aren't you using a wrecking ball instead of putting a man at
danger? I heard the owner was in there arc welding." <local builder,
unaware he was speaking to owner>
"That could ruin the boom. A wrecking ball needs something to stop
against, otherwise it swings free and the boom gets wrecked. Also,
the superstructure would transmit the energy of the ball all the
way around the frame, and we have no idea what that would do. The
entire thing could fail catastrophically, catching the ball in
the frame, pulling the boom with it; or nothing could happen."
<walks away diffidently, apparently insulted at being told how
to do his job>
All in all, a both sublime (in the danger) and ridiculous (in the failure)
affair, providing much entertainment for certainly the engineering-
literate layman such as myself.
[I've crossposted this liberally for the wide interest it may have.
Followups are set to chi.general only, but feel free to change that
if you like. But avoid cascading this, please!]
Daniel A. Hartung * "What took you so long?"
email@example.com * "An angry mob led by murderous guys
www.mcs.net/~dhartung/ * with torches...."
* "Don't let it happen again! -- Legend