The Hyatt Regency walkway collapse: A Lesson for all Engineers
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- Опубликовано: 9 фев 2025
- Hyatt walkway collapse was a tragic event that scared structural engineering profession and changed it for the better. It is a failure that all engineers need to learn from, that something that may seem like a small change can lead to a catastrophic disaster.
The Hyatt Regency has a catastrophic failure in two of its walkways on July 17 1981, It was a failure that scared kansas city and the structural engineering profession.
Any Major Structural failure like the collapse of the walkway at the Hyatt Regency is a tragedy, however, as engineering we must learn from such event to ensure that they never happen again.
Not only did the walkway have design issues at the Hyatt in Kansas City it there were also several times that the design flaw may have been found, however, despite the sign of structural distress being scene in the structure these where never followed up and lead to the catastrophic failure of the walkways in the Hyatt Regency. These are lessons that all Engineering should remember to ensure such a tragedy never occurs again.
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If you enjoyed this video you may also be interested in learning about the Citicorp Centre that was saved by a Student ruclips.net/video/QvGSspMwKp8/видео.html .
Wrong date--July 17, 1981
I teach quality assurance, metallurgy, and inspection. I use the Hyatt Regency Skywalk collapse as an example in my class. We do root cause analysis on it. I am sharing your video with the class after we do our reports. You have found many of the same issues we find in my classes while discussing this disaster. Well done.
I really liked this video. My senior engineer at the time told me this story when I was a graduate.
Another great case study young engineers should know about is the 17th Bridge in Atlanta why the standards were changed for post fixed epoxy anchors.
Thanks for the suggestion. Glad you enjoyed the video.
The trouble with that connection was that the horizontal part of the C beam section was being used as a horizontal cantilever and the vertical web was not being used directly to hold the load. The washer and nut underneath the C beam was too small and if a larger pressure plate spanning the width of the box beam such that the thick pressure plate would span the width and transfer the load directly to the vertical webs rather than in a cantilever effect on the horizontal parts.
The fact that the design was changed aggravated the effect but even the original design was wrong due to the horizontal parts of the C beam was being used as a cantilever and the welding of the two C sections was absolutely terrible. It was that small washer and that small nut that were at fault as they did not transfer the load to the vertical web of the C beam.
A thick pressure plate bridging the whole width of the two C section would have transferred the load directly to the two vertical webs and that would have been more than strong enough. I am surprised that no one saw this cantilever loading on the horizontal parts of the C sections.
Very well thought out and analyzed response. What I see on this post and including by the creator of this is a lot of references to a " small change" that was done. This was no small change by any means.
Hi Brendan, Thank for sharing this video. Its definitely a nightmare to be in such situation as a structural engineer of that project. Lesson learnt: Dont just ignore changes considering its a petty one.
Hi Prabin, it would have been so stressful for everyone involved. Thanks for watching and your support.
We walked across that walkway the week before it came down. Gut wrenching.
Hi Darlene, it would have been Gut wrenching. Such a tragic event.
I was on this upper walkway three days before the collapse. I was singing in the Hyatt with a choir. Six or eight of us walked over the walkway together and felt the movement. We were scared of the swinging motion and got off of it immediately. Ironically, my father (who was an engineer for another company) and mother, along with some of my father’s workmates (also engineers) were there that night at the fateful party. One workmate lost his wife as they were dancing. Watching the live news (apparently they got cameras in there pretty quickly as I think they were already there filming the party) was fascinating. The crews trying to get the walkways off of the people were so amazing. The equipment at first was not working. Then more came in. People were saved. However, if I remember correctly the pipes burst and some were drowned. It was a horrible night.
It must be haunting thinking back about it. Thanks for sharing your story. Also, I didn't read anywhere about swinging felt in the walkways wonder if that was a sign of issues.
@@BrendanHasty we initially thought it was supposed to do that but it was too much movement. Felt wrong. Sadly, not the only horrific engineering failure I’ve been around. I was standing on the shore in Jersey City New Jersey and watched the twin towers get hit and come down.
That day hunts me and I only saw it on TV.
@@BrendanHasty (haunting)
Thanks
Thanks for video loaded with highly accessible details.
Hi AVmen, thanks for your support. Sometimes the simplest details can cause big issues.
Thanks for the video. Didn't realize the original design only met 60% load. Add to that a change doubling such load and covering up the appearance of excessive deflection upon construction and the trap was set. As a highway engineer, I would sweat and bleed on my projects because I knew the responsibility involved. It is hard to do good engineering in our present lax environment fostering personal irresponsibility, often the 'engineer of record' is in fact a 'team', which is code for no one is responsible. And forget the old master-apprentice model, now the experienced engineers just assign to the kid out of school and attend to administrative tasks, ignoring the engineering aspect of supervision.
Hi John, yea something so small, but critical, which was overlooked, add a change. It should be a reccomnded case study for all engineers.
Steel design all comes down to the details.
Agree, engineering comes with a high responsibility, and if involved on a project everyone you feel responsible, ultimately requiring a suitably experience engineer taking responsibility. But it is becoming more a commodity, which needs to change, good engineering cost money.
I sweat blood on the project I do too.
One the best 'structural-failures' lesson! Simple statics showed it doubled the load on top walkway beam by changed load-path. I think tapered flanged paired PFC's were used - the manner of the road load on the flange tips only. Regardless, the STRUCTURAL DESIGN INTENT and load paths must remain, OR the structure element(s) reassessed and modified to suit. I believe follow through, documentation review and Quality Assurance was born from this. Good video content and production.
thanks guys, agree l Ioad paths must be followed throught, and some communication logs and QA procedure things may have been different. Always easier to say in hindsite. Glad you enjoyed the video.
@ 5: 47, It shows the side view of the rectangle support beam, it does not show the orientation of the rods as would be seen in an end view. Other drawings show the one piece all thread rods offset in the rectangle beam. As built and in the photos, the two-piece rods pass thru a hole in the seam weld in the center of the beam, it's weakest point.
Connections are serious business. Load paths are serious business. Lots of people do not think about these things. Minor changes during construction can have a big affect that might not be understood when the change is proposed. One of my previous bosses had a rule for us that if a contractor asked to make a change, we would never give an immediate answer. We would always go back to the office and consider the change and what might be affected. This was even prior to the Hyatt Regency collapse. Sometimes after considering a change we would discover all of the factors that went into the original design and how all of these might be affected by the change. Once everything was considered, we could decide if the change was acceptable. Not being able to give an immediate response did not make us popular with contractors and eventually these complaints from contractors affected our reputation with our clients.
Hi Bill, agree steel design is all in the connection and tracking the forces through the structure which needs special consideration. It is better to late with a response then give a wrong answer, that would hurt your reputation more.
this was such a sobering video, very well presented. the stuff of nightmares man. this is why i think Structural is one of the more scary branches of Engineering
Hi Sage, it really the stuff of nightmares, something so small can cause such a catastrophic failure. The human aspect making worse with other thinking that someone has checked it and the signs of distress during construction several times it should have been caught. Structural engineers really have a great responsibility.
@@BrendanHasty i had first learnt of this case a few years back, but the details you added with surveyors noting connection desegregation and even recommending further investigation to no avail and then the finishing crew too noting unusual deformation before covering it up with cladding was really disheartening.
i truly feel for the engineers that this happened to, even discounting the legal proceedings and near criminal conviction, the fact of knowing your errors caused such a loss of life is surely a mentally heavy burden to carry.
my only hope is that significant reforms came about due to this both where it happened and internationally. a tragedy like this need not happen twice.
The root cause of this disaster was the customer wanting to show off. Hyatt was noted for the dramatic look of their lobbies. They wanted these walkways to appear to be floating in air, hence the lightweight suspension rods. The FIU pedestrian bridge arose out of a similar impulse, the desire for something showy rather than safe. In both cases, you had Professional Engineers who wouldn’t say no, you may not build such a structure.
Don't forget to mention the severed sprinkler system pipes that were connected to tanks high above which quickly flooded the lobby nearly drowning the trapped survivors.
There was no shutoff valve to stop the fast flow of water. Another design failure.
Rescuers had to rip out the entry doors to drain the water from the lobby. They also connected fire hoses to the severed pipes to divert the still fast flowing water to the exterior.
This whole scenario was similar to the titanic disaster. The perfect storm of multiple factors that killed so many.
great informative video, keep making more videos like this. but can you elaborate a bit more the significance of that change in design by splitting the rod into two??
Hi Hariom Sharma, thanks for watching. The issue is around the load on the bolted connection not the rod. By splitting the rod it doubles the load the bolted connection needs to support as it needs to support level 4 and level 2, where the one with the continuous rod allows the load to pass through. Hope this clarification helps.
@@BrendanHasty okay, got it👍. Thank you. I want to be a structural engineer too, well i am in my 6th semester of my civil engineering and highly interested in structural engineering. So need some tips from professional like you😁
@@BrendanHasty Did the offset axes of the two loads introduce additional moment and shear in the horizontal member that summed the two vertical loads? These additional stresses would not have been present in the original assembly and may account for the apparent buckling of the horizontal beams shown in the photograph.
Such buckling may also have caused the ends of the rods to bend as the beam deflected under these twisting forces. At first, these strains may have been minimal, but over time, as repeated stresses and more permanent strains in the rods became evident, the connection bolts would have rotated out of the horizontal, further compromising their bearing capacity.
As a Cold Formed Metal Contractor I am wary of the casual changes that our Mechanics make when building out a complicated Steel Stud Structure like a Hip Roof or a curved assembly. I check everything they do and make sure they understand the implications of making any small change to the way loads and stresses are distributed in the framing. This process is complicated by the fact that it seems like very few Engineers in the USA understand the difference between Structural Steel, Wood Framing and Cold Formed Metal Framing. Evidently, the schools do not teach them to design in cold formed. So inexperienced Designers often presume it can be detailed just like wood, perhaps because the stud and joist cross-sections are similar in size and shape to the wood members they are intended to replace. (Case in point: I can't tell you how many times I have had to explain why you shouldn't cut a bird's mouth in the seat cut of a 1000 S 250 68 (50ksi) Rafter. They look at me like I'm all three heads of Cerberus.)
I haven't time to go on about this but suffice to say that a video from you defining the salient differences between CFMF and Wood framing would be most useful in educating more people on the subject. You could call it The Army of the Weak Strong Forces vs. The Army of the Strong Weak Forces.
Thank you for your instruction.
Erik
Apart from the fact that the load is doubled at the connection, there is also an additional moment and shear force at the level 4 connection (on the C-channel, since it behaves like a simply supported beam) due to the point loads from the ties below it. This also needs to be checked.
In my opinion as an engineer, the bad design was not as suggested here, and as in many other videos, but in the fact that the horizontal two FLANGES of the C channels were loaded as a CANTILEVER, and they did not transfer the vertical load to the vertical WIDER WEB, in a vertical manner. The vertical webs with a vertical load should have been used and not a twisting or torque load, on the flanges of the C beams. If wide THICK plates bridging across the two vertical wide webs were used with the loaded nuts, rather than using a thin washer with a small diameter, this would not have failed. Note, even the original design was no good as far as engineering logic goes, as it still loaded the two FLANGES in a cantilever torque mode, which should never be, in a C channel or an H channel. I would say that the original system would also have failed, as the welding holding the C channels together did not seem to be a good weld with no porosities and anyway, the original single rod was too close to the edge of the C beam. Exchanging the rods and placing the upper rod on the inner hole could have helped! . Thick plates with side limits, working in conjunction with the loaded nuts would even eliminate the need for welding the C beams, but I still would have used welding anyway.
Hi Carmel, I agree that original concept was poor to start and the back to back 'c' sections weakened the critical support location. as you suggest doubler plates would have likely solved the issue.
I am sad for the people and the engineer. He must have felt so guilty. Cannot imagine! we are people and make mistakes. that is a hard thing to have on the shoulders. then he realized it was not his fault but still, must have been stressful not knowing this right away! sad for the victims.
Agree, it is sad for everyone involved. People are sometimes quick to blame, and being the engineer on record he did share some of the responsibilities. Jack has try to impress on all engineers the responsibilities we design a building.
This is a case study for the steel design course at my University
This is a great casestudy was there anything else covered in your course?
Hi there. Iam a fresher in this. My doubt is, In a rapid changing world, how can we bring something new or freshness to every building that we design.
Thank you.
Hi Radhakrishna, Architect are constantly come up with new design that require unique structural solutions. I enjoy having to solve the problem that set us with. But wonder if design will revert back to older architecture.
I remember my boss Hank Kern was expert witness at the trial. They wanted to know how much a Steel detailer was involved and bears responsibility to the integrity of the steel structure.
Hi Reiner, would have been alot of interesting discussions, it seem odd to gave different constants detailing up different parts. In Australia we do all the steel details.
Thanks for sharing
Thanks for watching Kimmy
This case kept coming up during my undergrad years. I never understood what had really gone wrong. Thanks for the break down. I wonder if the original intent was for each floor level to be carried by a single continuous cable as opposed to the error of off setting another cable from the top slab to carry the lower ones and with this understanding how can this possibly be overlooked? But of course it easier to consider this now after the fact. Submittal process is a big process to consider and im always careful about it, in my case approving stair cases, and it still makes me nervous every time. Thanks for these great videos! Do you plan to do some design examples of real life work at any point? I think that would be awesome!! Great work!
Hi Ivan the orginal design was a single rod/cable from roof supporting two floors, thus each bolted connection only needed to support one floor. Guessing they must have had a miss calculated something as the orginal connection didn't work. They might have had a typical detail but check it correctly. At some stage the idea is to have some real world examples specially around concept design.
@@BrendanHasty Sounds Great!
@@BrendanHasty Sounds Great!
It happened on July 17, 1981, not June 17.
The engineer used two hot rolled channel steels to form a square steel beam, which is really a stupid design. Let alone the stupid hanging walkway by means of rods and bolts, I would have welded the nuts to the bolts if I was the structural engneer.
Hi, Xero it did seem like a strange design choice, that may have been directed by the architect that wanted the square edges. The whole design of the connection was the issue, not sure welding would have helped. RHS hangers may have made a bigger impact.
Difference in motivation. The fabricator gets paid to finish a job quick. They may not be as keen on lasting structure. They move on to the next job asap. That is how they have to act to survive. After all, there are Building Inspectors who will detect the smell of poop and issues vacate orders to protect occupants, they reason. Move-on or close up shop. They are motivated very differently than the Designers.
Some more feedback on your editing process - you need to record audio with the camera as well as the audio recorder and you need to give yourself an alignment spike in both recordings by clapping loudly or similar so you can properly align the audio to the video as it's slightly off and quite irritating. My 2c.
Hi Fredio, thanks for all the feedback. It is invaluable advice; it is hard to see all the things that I need to improve. My newer videos should have better audio, hopefully. I changed my recording process for audio. The audio should be synced; it is auto-synced in Davinci resolve. Always looking to improve. I cringe when I watch the videos I made last year.
@@BrendanHasty Awesome, good to hear. I'll stop giving you feedback on old ones, then :-D Sorry/you're welcome.
Happy to still have feedback on older one. You may pick up something I miss. Thanks for taking the time to help me improve.
@@BrendanHasty Sure, but I'll moderate it in light of what you said. Have a read of my other comment on this video, though, it's more of an engineer to engineer story share that you might appreciate.
Hi Fredio, I have it is good throughout discussion. I want to take the time to respond to your comments with the effort you have put in. But agree, from my research on the topic it was a lot of fingerpointing, and the separation of responsibility can cause issues.
5:48 That makes me SO angry. This is a classic case of engineer vs engineer. One of them knows maths and physics and the other knows how to weld and operate machinery and never the twain shall meet. I am not a professional engineer, but I do understand mathematics and physics to a university level and can also weld and machine. A story from my own experience dealing with an "engineer" in the past, good at his job, but his job didn't involve physics. We had problems with an 8.3 Cummins diesel flashing the oil pressure idiot light on in heavy seaways. For unrelated reasons the engine was out of the boat so I got hold of the sump and modified it extensively to solve those issues without increasing the height. It went back together and saw some big waves and we never saw the oil light again. Then at some point the engine came out of the boat again (again unrelated) and that "engineer" (RIP) saw my work, and cut it all out with a grinder exclaiming how bad it was. I was furious because he didn't understand the problem space nor the solution and had destroyed my good work. No big deal in my case, but in this video a similar thing that cost hundreds of lives :-(
Hi Fredio, Thanks for the amazing support. I agree some people only hyper-focus on what their responsibility is. As an engineer, it is important to understand the whole building process. The more you know, the better your design will be. It never hurts to ask questions and look over the wall.
I have had similar issues in design that you did(no failures, just design issues). There may be reasons for a certain solution; this typically happens during tendering; another engineering will review the design and may judgments but not taking the same journey we did to finalise the design. Sometimes there are reasons why then the building was design in a certain way.
neglectful corporate attitude. I'm interested in this and how it impacts Engineers in private practice. How do you navigate corporate forces and maintain your own integrity and project integrity/ safety as an Engineer? I"d like to see more content on this around Engineering ethics/ case studies are interesting.
Thanks for the suggest Matthew, agree that is can be a hard navigate corporate, integrity and ethics. I will looking to covering ethics with case studies.
Brendan Hasty wrote, "Keep you eyes open."
Hi Don, When on site doing inspections. Tho this is something I need to work on when I talk sometime I close my eyes. Thanks for watching
@@BrendanHasty Hi Brendan, Sorry for picking on you. I'm a perfectionist who notices everyone's spelling mistakes. (And I sometimes feel compelled to point people's mistakes out for them, in part, because I would like mine pointed out, so I can correct mine before more people see it.) Yes, of course I make some too, but usually limited to informal writing. And it's easy for me to see a mistake, but not so easy to know how to correctly spell something - a distinction I just realized. Anyway, in case I wasn't clear in my 1st comment, I was referring to your video text at 10:53 that says, "KEEP YOU EYES OPEN AND LOOK AROUND DURING SITE INSPECTIONS". I found it ironic that you left out a letter, both in that particular sentence, and in this video's subject, that tells the importance of small attention to detail. - That's probably why I like engineering failure type videos.
And your comment above to me isn't clear because you wrote gibberish "Tho rhis". I don't know if you have fat fingers (lol), you're writing on a tiny phone keyboard, or maybe you're eating a sugar donut and going into a diabetic shock as you type? Hopefully you're not driving and will recover. Otherwise, loved the video!
Hi Don, it is always great to get feedback. Agree tho really need to proof my text, the video editing software doesn't have spell checking. And spelling is my worse skill. I have set up a revised workflow to counteract this in my latest video.
Any other suggestions are welcome and appreciated, it is always hard to see what I need to improve, but spelling and grammar is definitely one of them as it detracts from the video, same with I sometimes mush(mumbling) words together when speaking working on that too, .
Anything else you found please let me know or anything to improve, as hash as possible. Thanks again.
BTW fixed my response. Thanks again. Was looking after my Kids, but that isn't a real excuse.
This was in the mid 70’s that was caused by fabrication error.
Now do the FIU Bridge collapse. You’ll find “good old Denney “ Pate. A P.E. is not a meal ticket for time servers who rest on their reputations.
Hi Gustav, the FIU Bridge collapse would be a good one to cover too. If you have any recommend sources let me know. Agree having a PE comes with responsibility and as engineers we need to ensure that Try all designs with the required care.
@@BrendanHasty the full NTSB report is available and the 3-hour complete NTSB meeting is on RUclips. Search “NTSB FIU bridge”. The OSHA report is available and also easily found via “OSHA FIU bridge”. These are long reports and you have to put in some time, if you’re serious. W. Denny Pate is a member of the TDF hall of fame. People with money and power can sometimes get away with murder, or at least manslaughter, like your friend Jack, who was the “G” in GCE, the prime engineering contractor of the Hyatt.
Was the goal of the change in design a money saving decision?
Think that it wasn't to save money, it was just an element that was miss. The design responsibility was shared which confuses things, and passed to a 3rd party who made an assumption that it was previously designed and approved.
But in the end it was something that was missed and it shouldn't have been.
Yeah but, I guess I would call this a single point failure. You know like that thin plate they used on that I-40 bridge? Maybe a stiffener / load distributing plate above and below that weld creating the box frame. 50 years from now some kid who has no dog in the fight will find the best explanation. IMHO.
It is a single point of failure, yes, but there was more the two connections but they all had the same deficiency. There would have been several way it could have been address.
@@BrendanHasty I agree. It's hard to make an objective comment because hind site is 20/20. Working with a former auto mechanic in a field that used heavy equipment for patient positioning, I learned much about load distribution and not having stuff fall apart. We had many WTF discussions when the reports started coming out about the walkway.
Structural engineer must do the calculations , that is the meaning of Design. If not , you can ask an artist, or your mum, or ...anyone to do a "design". It is criminal negligence to assume everything 'looks good when other peoples' lives are at stake. Engineering should not be practised by people who do not realise that their work is a 'life and death matter'. If not to do the actual maths that is required, why else should an engineer be involved in any structure?
5:38 OMG
good video, thank you. for those of us non-native english speakers - please consider speaking bit slower.
Hi tentomek, thanks for your support. This will be something that I will work on.
July 17. Know your facts.
Thanks for the correction, sorry for the mistake.
You say “Jack” to humanize him. He was a principal in the firm he “worked for”. He “quickly did the numbers” but had put his P.E. seal on the sign without doing the numbers in the first place. The firm was party to the delay in sequestering the wreckage. The KC Star hired someone to take the key photos of the beams with the bolts pulled through. The original design already was defective. The owner (Hallmark) requested a review of ALL STEEL because of a ceiling failure in construction and the design firm did claim to have done the full review. Your presentation is shoddy and seriously biased in favor of an engineer who was criminally negligent.
Hi Gustav, using "Jack" wasn't an attempt to humanise him just a way to tell what happened , and agreed he was the lead engineer overseeing the design, thus his responsibility. (Which I am sure he would agree with). I also noted that even the orginal design in the orginal configuration didn't work, let alone doubling the load from later changes. How this was overlooked is really concerning, with multiple people at fault as the design responsablity was split from my understanding. As for laying claims of criminal negligence that is for the courts, which I noted the outcome of these proceedings.
It wouldn’t be right to de humanize either
Its Lessons Learned...lol....
Both versions of the word are actually correct and widely used in the English-speaking world, but there is one small difference between the two words. 'Learned' is the preferred way of spelling in the US and Canada, while 'learnt' is favoured in British English
Lesson L-E-A-R-N-E-D !! What’s happening to English, these days? It’s collapsing just like those catwalks.
Both versions of the word are actually correct and widely used in the English-speaking world, but there is one small difference between the two words. 'Learned' is the preferred way of spelling in the US and Canada, while 'learnt' is favoured in British English. Being from Australia we speak British English.
Check this link if you don't believe me
www.grammar-monster.com/easily_confused/learned_learnt.htm
@@BrendanHasty Sorry. My bad
All good Jon, learn something new everyday. Thanks for watching.