Here are some photos I took of the demolition of Lindheimer Observatory in the Fall of 1995. You should also check out Rob Lentz's Lindheimer Observatory page for more photos, movies, and other Web pages about Lindheimer.
The initial demolition attempt used explosive charges. The observatory did not topple as expected. Instead, the supports merely buckled, resulting in a new Leaning Tower of Northwestern University.
After the unsuccessful attempt using explosives on Wednesday, the demolition crew tried other means, including using pulleys and earth-moving equipment, to bring down Lindheimer. By Friday afternoon it was clear these methods would not work either, as these photos attest.
Rob Lentz reports the following from a 4 pm Friday (September 15) press conference:
The demolition company has received a variance from the city to allow them to work 24 hours a day over the weekend in order to cut down the exo-skeleton piece-by-piece. This will be accomplished by hanging two men in a basket from a crane (a second crane may also be used). These men will be wielding 5-7 foot torches to insure their safety when the beams pop as they are cut through. At some point, by Monday night (each beam will take a few hours), they expect the structure will just crumble. The beams will be allowed to fall freely from where they are.
Here are a couple of early morning (1 a.m. - 2 a.m.) shots. The demolition crew is now fanning the superstructure with a blowtorch (I kid you not) in order to cut away the superstructure struts one by one. Could be a long night for those guys :-}.
These shots show the bright flare of the blowtorches and little else. My digital camera fares poorly in dim lighting conditions.
Leaning Tower of NU #34 (blowtorch flare)
Leaning Tower of NU #35 (blowtorch flare)
Dan Hartung posted a nice summary of events through Friday to some local Chicago USENET newsgroups. Here is the text of his message. I hope he doesn't mind my reposting it.
From dhartung@MCS.COM Sat Sep 16 02:05:01 CDT 1995 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?!""It's a landmark, a tragedy. What kind of people are running this University????" "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." "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." "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." 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?" dhartung@mcs.com * "An angry mob led by murderous guys www.mcs.net/~dhartung/ * with torches...." * "Don't let it happen again! -- Legend
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Last modified by pib on March 21, 2000.
