I don’t see any moral responsibility on Hyatt’s part for the disaster.What should Hyatt have done differently? Sure they pushed for getting the job done quickly, but I can assure you every construction project is under pressure to be completed swiftly.
It’s simply a fault of engineering .
And I find memorials that simply hilight disaster a disgusting waste of resources unless they invoke memory of heroic response. I haven’t heard of anything special about the response to the skywalk collapse.
Correction: my post strongly implies Gillum stamped the modified design. He did not; but he did stamp the original questionable design which sent the massively-threaded rods through the welds on the channel beams. I apologize for the unintentional misdirection.
As I once was a field engineer for a construction company , submitting design changes to the responsible engineering firm to reduce time and cost, I always found this incident somewhat sobering, and I thought I had
a good understanding of the problem. Apparently the threaded rods holding up the floors were designed properly, but the original design was for one rod at each hanger support with individual nuts on the rod for each floor. These nuts had to be turned a long ways on the rods.
Some engineer in the field trhought he had a better design by cut up the rods so that the top suspended floor had its own support rod as well as a second rod holding up the next floor which also had a second rod holding up the third floor.
The trouble is nobody thought of the nuts** which were designed to hold one floor only** . Same rod, same nuts right?
Instead, now the top suspended floor nut was holding up three floors instead of one, way beyond the safety factor which usually is 2.
The guy who proposed that design change is probably still not getting a good night’s sleep.
I think you’re saying it, but just to emphasize, the nut itself didn’t fail, it was pulled through the welded joint. There are photos on here: http://ethics.tamu.edu/ethics/hyatt/hyatt2.htm
Ah ! I get it.
No, that was the second change, according to the stories in the Kansas City Star at the time.
I’ve never seen those up-close pictures, and I have to say that’s a very odd design. Just way more complicated than it needs to be. I don’t claim to be an engineer, but I would have thought you’d go for the simplest design possible. But as I said, I’m not an engineer and maybe I’m missing something.
I know the failure had something to do with the nuts, but I guess I either misremembered or never properly understood it before.
I know the doctor who directed the triage at the scene, and I have his collection of books, papers and videotapes, which I am using to expend the Wikipedia article.
The original design was made of two deep U shaped pieces, one on the bottom facing up, the other on the top facing down. The steel fabricator did not have those pieces in stock and used two shallow pieces, one on the left, the other on the right.
I’ll have to dig through the newspapers. I might have it here, although the doctor’s collection focuses mainly on the medical aspects. I’ll probably have to head down to the Main Library, something I had been planning on anyway.
The KC Star (or Times if it was in the morning paper) went back before the official drawings.
Agreed. But in your professional opinion, would two U-shaped channels fitted top to bottom, with welds on the sides, have held? That design would not have any holes through welds, and would have required that the nut rip through holes in solid steel. It still would have been marginal, but would it have failed?
As I said, I read the newspapers, and will be going back and re-reading them to add more references to the Wikipedia article.
Not clean hands, but one of the only parties accepting any responsibility at all.
Everyone talks about “the original design”, but as I recall from the Kansas City Star series, it was compromised once before what is being called the “original” design was drafted.
That’s both interesting and admirable of you, honestly.
But it does not bear on the mechanical design. That was my only reason for bringing that up. Since you say you’ve been doing scholarship on it that explains a lot, however, I think my sources show different answers than what you were saying, which is why I wanted to talk through some detailed herein.
According to Shurghart et al., the construction contract was issued on February 22, 1978. On August 1, 1978, the drawings were sealed (meaning he put his PE stamp on it) an issued for construction by Gillum. It is true there were other designs done beforehand - one on March 30, and one on May 26, but these designs were not sealed nor issued for construction. So for the purposes of liability, we can only go by the initial sealing (August 1). I scanned the pertinent drawing here:
http://www.coalgoddess.net/files/Pictures/1112/1Aug1978.jpg
This appears to me that the first design was using the welded beams with the rods passing through the welded area where the two channel beams meet.
If I understand you correctly, the moment of inertia would be in the weak axis - think of a 2x4 piece of wood being loaded on the long axis, versus the short, for a mental exercise of what I mean - in one way it is much stronger than the other. Turning the channel beams 90 degrees would mean they would have the wrong moment of inertia for the loading, and I cannot imagine when that would ever be done in any structural application. In a nutshell, I doubt very much it would have held, and might even have been worse. Now if you are positing some sort of composite beam with the same moment of inertia as the channels…I don’t know, honestly, that also would be a highly unorthodox construction. Again, I wonder why they didn’t just use pre-made box beams, or wide-flange beams for that matter. Perhaps it was aesthetics, perhaps cost. That would be an interesting question to answer, I feel.
It is entirely true what you say - that the design was modified to be inherently unsafe. But what I’m saying is that the original design was poor to begin with, and possibly unworkable, and that regardless of whether it would have worked or not, there were opportunities for oversight of the modifications, but Duncan failed in his professional obligation to do the math to check. IMHO he made a rookie mistake in statics, the sort of thing that at first glance looks one way, but when you run the numbers you find the loads are much higher than you’d like.
And yes I made a lot of mistakes in statics; I can almost sympathize with the engineers involved. I hated mechanical design, because a lot of things which look “obvious” aren’t, and vice-versa, which was one reason I jumped at the chance to get out of it and work on energy, instead of structures. Thankfully I’m pretty sure everything I designed is still standing, but then that’s because I designed things with an SF of 10 or more, because they were one-off structures and the cost differential was very small.
Thanks.
From what I remember, the top-bottom composite beam design was the same height and width as the side-side composite beam design finally used.
I’m sure you’re right. The split rods were the final straw, but is it possible the split rods would still be there if they were not going through holes in a weld.
I’ve never designed any thing like the skybridges. I have hung speakers and lighting equipment over stages in Municipal Auditorium, and sweated every minute until they were back down on the ground.
I’m reading an unpublished manuscript about the Hyatt tragedy right now. It says about the Belger Cartage cranes:
The giant truck cranes had been waiting for six hours to do something to help, but it wasn’t until past two o’clock in the morning that the rescuers were able to get permission from Hallmark to allow the crane booms to poke through the windows of the west wall.
That is nothing short of astounding. Belger Cartage was about five blocks away, I can’t imagine these crane operator sitting on their hands for six hours, waiting to rescue people.
I concur, it is very possible.
To add to my previous response.
Its been many years since I took statics in school, over 35 years, but I vaguely remember having to check for the allowable bearing stress of a beam at the connections and that depended on plate thickness. It was standard protocol. Just where do you look for allowable bearing stress of a beam with welded joint ?
I"ll guess that a heavier fender washer or two of the same diameter as the “box beam” would have been much better.
The incident was used as an example during an engineering course I took, and I wondered why a single support goes through the center of a hollow-beam instead of, say, having two supports through the flange of an I-beam on either side of the web.
you…gotta…be…fucking…kidding…me
People crawling through twisted metal and concrete wreckage to try to save others? Wreckage that could shift and kill the rescuers without warning? People dressed for a formal party kneeling on broken glass while choking on concrete dust so that they could at least hold the hand and give comfort to the dieing victims?
Go back and look through all your other posts to this board and see if you’ve ever said anything else that sounded as stupid as your comment above.
Indeed. Here is a quote from my friend from the unpublished manuscript. He’s said similar things in the years I’ve known him, but this was really fresh:
[QUOTE=Doctor Joe]
I’m satisfied by what I did professionally, but as a human being, it was very difficult. You walk into a room and there is chaos and further danger for the rescuers. There is water, blood, and guts on the floor. There are people decapitated. There are people cut in half. People dying every minute. People screaming in agony. I thought I was pretty hardened. I’ve been doing my work a long time. I’m a specialist in emergency medicine. I’ve seen individual cases come into the emergency room badly mangled, but never have I seen anything like this. A beautiful young girl died in my hands; I couldn’t get her out because she was pinned by dead bodies.
There is no language to depict the sounds, smells, and sights of of death and destruction that night. I suppose that any one of the trapped victims was not too much different from what I had seen once or twice in the past, but when you find hundreds of them like that all at once, some dead, some alive, and in the setting in which it occurred – it just had a tremendous, tremendous impact on everyone.
Normally when I see the injured, those who been in a terrible head-on collision, for example, it’s always in my emergency room were at least I have all the proper tools, medication and lighting. At least have a chance to try to save them in a place that has been sanitized and relatively germ-free. At the Hyatt, my God, we had use the hotel’s butcher knives and firemen were asked amputate with chainsaws. I had never before seen with chainsaw does to a human - believe me, it’s horrible. And the filth. People had been crushed to the point where their insides extruded and their intestines had burst. I couldn’t sleep for months, and if that much impact on me, imagine the lay people who were there – the party-goers, the construction workers, firemen and policemen, the volunteer help, the people who never seen or imagined such horrors can exist. It has messed me up like it has everybody else. I was emotionally and physically wiped out. I still can’t get it out of my mind. There are still sleepless nights and terrifying dreams. I’ll be sitting around and I’ll get flashbacks. Something pops into my head. An odor, or something I’ll see, will remind me. I still can’t shake it. It’s inconceivable that anybody who was there will be able to get out of their minds for the rest of their lives.
One of things that came out of this experience for me is that there should be mandatory psychological or psychiatric consultation for everybody involved. In disasters like this there should be mental help for everyone, without any stigma. Because everyone is a victim.
[/QUOTE]
He told me recently that various rescuers used to call him, trying to deal with the what they had experienced. One guy, a construction worker who was using a jackhammer to cut holes in the concrete for the medical personal to crawl through was not able to handle it, and wound up taking his own life.
Yeah, I’d say a memorial is needed.