Hyatt Regency walkway collapse

Suspended walkway in Kansas City Hyatt lobby. As-designed: single threaded rods through the C-channels of multiple walkway levels, requiring a nut threaded up many stories during erection. Erection changed it to extended/doubled rods, converting straight tension on the threaded rod into shear loading on the box-beam C-channel — a connection never sized for shear. Procedure existed for sign-off on changes; it was not followed. 114 dead, 200 injured; the building lobby was subsequently reduced to two stories.

Things are not always the way they're supposed to be, and that usually is not a problem. But there's a fairly famous problem — the Hyatt Regency Hotel in Kansas City.

Student: I'm from Kansas.

There's actually a book — this one right here. [Tom holds up Petroski's book.] Henry Petroski. Does anybody know who Henry Petroski is? He's a professor down at Duke University. He wrote this book, To Engineer is Human: The Role of Failure in Successful Design. He was elected to the National Academy of Engineering the same year I was, for having written this book, with the idea that we only learn from our mistakes. The Hyatt Regency collapse is in here, and if you watch some of the other videos I'll talk about that and use his book. The theory is we keep on building things bigger and bigger until we hit the limit, and then we have a big failure, a bunch of people die, and all of a sudden we say, what's going on? Like the space shuttle Challenger, someone brought that up the other day.

Structural analog. Kansas City, circa 1980. Tension threaded rods (not stainless) in shear connection failed in indoor atrium during a party; several hundred casualties. Tom invokes it as ethical-stakes anchor for his Miami decision: tension connections in occupied space.

I remember the Hyatt Regency collapse in Kansas City back around 1980. They had walkways — it was an indoor atrium, and they had tension threaded rods. They weren't stainless steel. They actually had a shear connection. The designer had designed it as a straight-through connection, which may have been strong enough, but you couldn't run a threaded rod for 60 feet. So the erection detail had offset, with one threaded rod with a nut and another one with a nut on the top — it was a shear connection. And all of a sudden that shear connection couldn't take the load, and the big party, a couple hundred people died. Came crashing down four or five stories on the inside. So I'm sitting there thinking, this is sort of like the Hyatt Regency — except here you've got people sipping chardonnay down below rather than up on the walkway, so they wouldn't fall, they'd just get crushed. Hyatt Regency, but still a tension connection. Stupid. Super stupid. Why do you make tension connections?

The lecture's centerpiece forensic case. July 17, 1981, Kansas City. The original detail design called for solid hanger rods, threaded only at the ends; field fabricators, unable to thread a nut 15 feet down a solid rod, substituted a two-rod stagger that doubled the load on the upper rod's C-channel connection. The change was approved (or missed) under the high-volume change-order process. 114 dead, 200+ injured. Used to illustrate the as-designed vs. as-built distinction and to introduce the engineer-of-record concept. Cites Petroski's *To Engineer is Human*.

Let me give you an example of an as-built that didn't quite do it the way and caused a serious problem. This is the Hyatt Regency Hotel in Kansas City, July seventeenth, 1981. People who have been to Hyatt hotels know they have these big tall atriums. I lived in Atlanta, Georgia as a teenager, I think when they built the Hyatt Regency Atlanta, which was the first big Hyatt Regency with a big atrium. That building is still there; they built a bigger Hyatt right next to it. The old one was only 40 stories tall, the new one's like 60 stories tall, but people still go to the old one to commit suicide. They go jumping off the balconies, and so you're sitting there eating your breakfast at the restaurant on the atrium floor, and all of a sudden someone comes splat right next to you. Doesn't happen that often, but I remember as a teenager — I moved from Atlanta when I was 13 or 14 — I remember in the newspapers, this big 40-story atrium was the selling point for the Hyatt Regency. Everybody in Atlanta had to go see this atrium. Then about six months later people started using it as a place to kill themselves.

Mentioned only as a future example Tom "may go through" — flagged here because it appears in the corpus catalog and is one of Tom's recurring teaching cases.

That's what I mentioned earlier — Henry Petroski wrote To Engineer Is Human. He was elected to the National Academy of Engineering the same time I was, mostly because of this book, not for any scientific things. Copyright 1982. He's a professor at Duke. Very accomplished spokesman. Goes around giving talks about what it means to be an engineer, the ethics of engineering. Things like the Hyatt Regency collapse, which I may go through, is one of my examples.

Single-sentence reference, invoked as the worst-case scenario for engineer-of-record liability that justified Tom's refusal to sign off on the Miami Art Museum redesign.

So they started doing things. They went back to Sandvik in Sweden, and Sandvik said, use the duplex stainless steel. They said, well, can we use the duplex stainless steel? I said, sure, as long as you don't have any weld details. Can't weld this without real problems. It's good for pipe, and oil wells, and sour oil wells where you have hydrogen sulfide. We went through several things, and again, everybody's asking me — even though I was the idiot who didn't know what I was talking about when we had the first meeting — everyone is now asking me to approve the design. I said, nope, I'm not being paid to take the liability for this building, particularly if it comes crashing down like the Hyatt Regency collapse, which killed a couple hundred people. I would give advice, but I was not going to sign off. There is an engineer of record who has to sign off legally on this design, and I was not going to assume that responsibility for the peanuts they were paying me for consulting. If someone's going to allow me to make a couple million dollars profit, I can afford to go buy liability insurance. But anyway, those are other stories.

Foreshadowed for next week's detailed treatment. Kansas City Hyatt, ~1980-1981, ~200 deaths when atrium walkways collapsed during a party. Used here as example of code-failure-leading-to-code-update; also Petroski's case.

Remember how the code came about historically. The code was written because we learned about failures. I showed you the picture of the Brockton, Massachusetts shoe factory. [Tom holds up Henry Petroski's To Engineer Is Human.] Here's Henry Petroski's book — this professor at Duke University, who wrote it about 1980. He's written a bunch of books since. Copyright 1982. To Engineer is Human — he's a civil engineer. He talks about the role of failure in successful design. I'll use an example next week out of this — the Hyatt Regency walkway collapse. None of you were born at that time, I don't think, but it killed a couple hundred people in Kansas City.