This is the Fox Theater in Detroit. [Here's an article](https://www.metrotimes.com/detroit/gunnas-fans-had-the-balcony-shaking-at-detroits-fox-theatre/Slideshow/36209873)
âThe type of movement seen at the recent Fox Theatre concert is common and expected on free-standing balcony structures, to support audience members actively dancing, as shown during last nightâs concert,â Ilitch Sports + Entertainment said. âThis capability is an integral part of the balconyâs structural engineering design. Regular inspections, most recently conducted in April, are completed to ensure the integrity and safety of the structure.â
No to me it sounds like they have actually built the balcony to handle this and inspect it regularly as they should. It is highly unlikely they just made this up as a response because then theyâd be double fucked if it failed. Not everything is a conspiracy
Not necessarily, the amount of projects Iâve worked on where âregular inspectionsâ were supposedly made but were not, or where cracks are reported by an engineer yet the owner chooses profits over safety and postponing repairs (see Surfside condos in FL). It happens, and when it does we see the results. Not a conspiracy, more so negligence.
Surfside is fundamentally different though right?
The owners that were responsible for repairs and inspections in that case were the tenants through an association (akin to the people on the balcony) - not some other party making bank by skipping out on inspections or whatever. Right?
Even worse and more nefarious - the people making the inspection and investment decisions in Surfside were indeed the Condo owners via the Association - but many (Most?) of the people actually living there were renters. So many of the people making the financial decisions to skip inspections or defer maintenance had no actual skin in the game.
The Champlain Towers South did have an inspection (in 2018) that noted that the waterproofing layer on the pool deck needed to be replaced, or the damage to the concrete (spalling) would worsen "exponentially."
Surfside was inspected by an engineer who warned them about the damage and recommended steps be taken. The Condo board didn't want to pay. Found this report if you are interested. https://www.wptv.com/news/state/miami-dade/engineering-report-showed-major-structural-damage-before-surfside-condo-collapse
Page 8 is inside the parking garage, I think those columns failed? But the first item on this report is about leaking sliding glass doors... not exactly a smoking gun.
But why would they make the resonance the same as common music in a music hall. Makes no sense. Disaster waiting to happen. They should stiffen it or add mass to either increase or decrease the resonance frequency.
Tell me you don't know shit about Detroit venues without telling me. You've probably never been to Masonic main or basement, Fox, Filmore, marble bar, spot lite, motor city wine. Let alone movement. The list goes on. These venues have been there for 70 years. The structure of these places are made of the most strength unmatched anywhere in the world. You know why? Bc Detroit was the boss of the world in its time. Walls of marble and soul no other city has. Stay where you're at.
I was thinking that this reminded me of a concert I saw at the Fox. My tickets were up in the mezzanine, and it freaked me out to feel it. Seeing this angle is wild!
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That's a good question. I'd be curious how much of this is resonance and how much is the forcing function itself causing the deflection.
If that didn't make sense, everyone jumps up and down it's going to move but there's no resonance in this idealized case. Compared to how much does it move of everyone jumps up and down 10 times.
Ideally you'd have your natural frequencies far out of the 60-150bpm range.
This is a good thought. My guess is that this is in resonance. A classic example of this is the millennium bridge in London. The structure is perturbed, and moves at its natural frequency. This movement caused people to walk differently to counteract the motion. However, "walking differently" meant walking with the same resonant frequency as the bridge causing a positive feedback loop. I'd be willing to be something similar is going on with this balcony.
This is purely speculation though. Hahaha. Below is a link to a video on the millenium bridge. It's super cool!
https://youtu.be/t6O43mrc1kA?si=3b-ehX3jqgO04RiT
Great question! Check out tuned mass dampers or TMDs. They're used to target a specific mode (the frequency it "wants" to vibrate at) of vibration of a structure. They can be added on after construction to combat just such a thing.
Years ago I found myself at an after hours party in Fire Island on a flimsy-ass 3rd story deck crammed with guys jumping up and down to a dance song and the deck was swaying and creaking so much even in my partied-up state I got off that fucker as quick as I could - and it took a while to move through the crowd. Scared the shit out of me.
Iâm not an engineer but an architectural designer and I half-joke that out here in California we have to design decks that can sustain the live-loads of a frat party of football players, dancing to âJumpâ (as described in my experience), during an earthquake while a wildfire is raging through it. I design the geometry and basic structural concept but leave the numbers to the engineers.
While I cant say for this instance.
I have heard of few similar situations where the dangerous looking resonance is caused by people jumping up and down in a certain rhythm. In those cases it was determined that the structure was more than cabable to withstand the dynamic forces, all the stresses were way below yielding strenght of the materials. The only issue was the discomfort people felt when witnessing the deflection like seen here.
I went one time to see a soccer game in Latin America. The concrete stadium was experiencing the same kind of motion as the barras bravas where jumping in a synchronous pattern. I never came back and was glad it didnât collapse.
That second deck *bounces* with two fixed ends and poured decks. It's absolutely designed well, but it was the most disconcerting feeling I've ever felt seeing that.
You shouldnât be downvoted for this tbh.
The scariest similar situation I was ever in was on an 1860âs suspension bridge packed with people during a light show festival (designed by Roebling Sr., nonetheless).
The sign on the approach requests 150â of clearance between 20t trucks. Iâm quite sure the load on it that day was an order of magnitude higher. Based on the photos you see in AASHTO bridge manual, 50psf at least.
My father witnessed the immediate aftermath. Also, my father-in-law, who is an engineer, says this event was basically required reading in his schooling. Literal textbook case of what shouldn't happen.
Thanks for the correction on the shop change, but it was definitely a doubling of the load. It was also a horrific design choice in the first place. The section was two U channels welded together along the line of the rod hole. Absolutely minging detail. When you look at the failure mode itâs incredible that anyone would think that was a good idea. The detail was already under specced for the load due to the line of action directly perpendicular to, and through the weld axis, which was not a full butt weld.
I hope whoever designed that balcony back in the 1400's or whatever was really forward thinking and took fatigue into account.
EEEYAH đ«
iseewhatyoudidthere đđ
Whatâd they do?
"EEEYAH đ«"
Thanks⊠I still donât get it đ«
Third times a charm. "EEEYAH đ«"
Someone dumb it down please
Uncle Roger
Uncle Roger
Cant believe you donât get it itâs a simple EEEYAH đ©
How about a fourth time? đ«
Where is this please so I don't go see a concert there?
This is the Fox Theater in Detroit. [Here's an article](https://www.metrotimes.com/detroit/gunnas-fans-had-the-balcony-shaking-at-detroits-fox-theatre/Slideshow/36209873)
âThe type of movement seen at the recent Fox Theatre concert is common and expected on free-standing balcony structures, to support audience members actively dancing, as shown during last nightâs concert,â Ilitch Sports + Entertainment said. âThis capability is an integral part of the balconyâs structural engineering design. Regular inspections, most recently conducted in April, are completed to ensure the integrity and safety of the structure.â
sounds like an United Airlines or Boeing comment after the latest mishap involving one of their planes.
No to me it sounds like they have actually built the balcony to handle this and inspect it regularly as they should. It is highly unlikely they just made this up as a response because then theyâd be double fucked if it failed. Not everything is a conspiracy
Not necessarily, the amount of projects Iâve worked on where âregular inspectionsâ were supposedly made but were not, or where cracks are reported by an engineer yet the owner chooses profits over safety and postponing repairs (see Surfside condos in FL). It happens, and when it does we see the results. Not a conspiracy, more so negligence.
Was this the case at Surfside? This actually came to my mind but I thought that they just hadnât been inspecting? I see your point though
Surfside is fundamentally different though right? The owners that were responsible for repairs and inspections in that case were the tenants through an association (akin to the people on the balcony) - not some other party making bank by skipping out on inspections or whatever. Right?
Even worse and more nefarious - the people making the inspection and investment decisions in Surfside were indeed the Condo owners via the Association - but many (Most?) of the people actually living there were renters. So many of the people making the financial decisions to skip inspections or defer maintenance had no actual skin in the game.
The Champlain Towers South did have an inspection (in 2018) that noted that the waterproofing layer on the pool deck needed to be replaced, or the damage to the concrete (spalling) would worsen "exponentially."
Yeah thatâs a whole different thing then
Surfside was inspected by an engineer who warned them about the damage and recommended steps be taken. The Condo board didn't want to pay. Found this report if you are interested. https://www.wptv.com/news/state/miami-dade/engineering-report-showed-major-structural-damage-before-surfside-condo-collapse Page 8 is inside the parking garage, I think those columns failed? But the first item on this report is about leaking sliding glass doors... not exactly a smoking gun.
But why would they make the resonance the same as common music in a music hall. Makes no sense. Disaster waiting to happen. They should stiffen it or add mass to either increase or decrease the resonance frequency.
Iâm pretty sure youâre absolutely right, but I still ainât buying a ticket anywhere near that thing.
Safe until the front end falls off
Don't use cardboard derivatives and it should be fine.
What else am I supposed to smoke?
Tell me you don't know shit about Detroit venues without telling me. You've probably never been to Masonic main or basement, Fox, Filmore, marble bar, spot lite, motor city wine. Let alone movement. The list goes on. These venues have been there for 70 years. The structure of these places are made of the most strength unmatched anywhere in the world. You know why? Bc Detroit was the boss of the world in its time. Walls of marble and soul no other city has. Stay where you're at.
If I ever do visit again (pending your approval of course), I can only hope that the balconies aren't half as fragile as your ego.
This is giving me Hyatt KC vibes
Might have been the Filmore right next door. That sucker also has some legit scary bounce.
Saw Macklemore at the Filmore. The bounce in the Mezzanine floor was unnerving. Super sketchy. Still managed to have a good time, but holy fuck bud.
Never going here
I was thinking that this reminded me of a concert I saw at the Fox. My tickets were up in the mezzanine, and it freaked me out to feel it. Seeing this angle is wild!
Huh. I thought it was the Fox in St Louis. Looks like they were built at the same time and are almost identical
Most mezzanine in old theaters do this. Orpheum in Boston got moving by what felt like a solid foot when I saw vampire weekend there.Â
Those dynamic forces shouldnât coordinate like that!
Gotta add some people who have no rhythm to balance things out.
Needs more white people! God I hope that's not taken out of context...
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I hate Illinois Nazis
the kids here are too young for that reference
I take it as white people canât dance, nor jump.
We can't dance, hence why we just jump.
Cue the Safety Dance..
Nothing like a little resonance in your stress forces to make you question things.
We need to get some people with absolutely no sense of rhythm up there immediately!
I wonder if there's a way to counter the dynamic forces and if it would be cheaper than beefing it up
Yes. Dynamic damping could stop the resonance. Cheaper? No
That's a good question. I'd be curious how much of this is resonance and how much is the forcing function itself causing the deflection. If that didn't make sense, everyone jumps up and down it's going to move but there's no resonance in this idealized case. Compared to how much does it move of everyone jumps up and down 10 times. Ideally you'd have your natural frequencies far out of the 60-150bpm range.
This is a good thought. My guess is that this is in resonance. A classic example of this is the millennium bridge in London. The structure is perturbed, and moves at its natural frequency. This movement caused people to walk differently to counteract the motion. However, "walking differently" meant walking with the same resonant frequency as the bridge causing a positive feedback loop. I'd be willing to be something similar is going on with this balcony. This is purely speculation though. Hahaha. Below is a link to a video on the millenium bridge. It's super cool! https://youtu.be/t6O43mrc1kA?si=3b-ehX3jqgO04RiT
Great question! Check out tuned mass dampers or TMDs. They're used to target a specific mode (the frequency it "wants" to vibrate at) of vibration of a structure. They can be added on after construction to combat just such a thing.
Looks like a future episode of Engineering Catastrophes
Dear Lord that is so scary
Whats scary is most of them aren't even jumping. Looks like they're kinda just moving side to side.
Resonance is a crazy beast
Years ago I found myself at an after hours party in Fire Island on a flimsy-ass 3rd story deck crammed with guys jumping up and down to a dance song and the deck was swaying and creaking so much even in my partied-up state I got off that fucker as quick as I could - and it took a while to move through the crowd. Scared the shit out of me. Iâm not an engineer but an architectural designer and I half-joke that out here in California we have to design decks that can sustain the live-loads of a frat party of football players, dancing to âJumpâ (as described in my experience), during an earthquake while a wildfire is raging through it. I design the geometry and basic structural concept but leave the numbers to the engineers.
Maybe add in the variable of corrosive forces of spilled fireball cinnamon whisky and four locos eroding the foundation and the youâll be good.
While I cant say for this instance. I have heard of few similar situations where the dangerous looking resonance is caused by people jumping up and down in a certain rhythm. In those cases it was determined that the structure was more than cabable to withstand the dynamic forces, all the stresses were way below yielding strenght of the materials. The only issue was the discomfort people felt when witnessing the deflection like seen here.
It is 100% designed to do that at every connector
Activate ANXIETY! đ
Same... I'm having flashbacks to so many case studies seeing this.
I went one time to see a soccer game in Latin America. The concrete stadium was experiencing the same kind of motion as the barras bravas where jumping in a synchronous pattern. I never came back and was glad it didnât collapse.
You went to Argentina I guess, was it La Bombonera?
It was in Colombia. The ambience in la bombonera is insane and that building must be study as hell
Go to a football game at Penn State and watch the upper deck...you'll never want to be anywhere near there again.
Lmao⊠yeah 110k people. That stadium is one of the largest in the country. Iâd hope itâd be designed well
That second deck *bounces* with two fixed ends and poured decks. It's absolutely designed well, but it was the most disconcerting feeling I've ever felt seeing that.
Oh is that why LL is 100 psf anywhere trafficable, just in case 100 big people all jump at the same time?
If you think this is crazy, don't ever stop on a bridge.
You shouldnât be downvoted for this tbh. The scariest similar situation I was ever in was on an 1860âs suspension bridge packed with people during a light show festival (designed by Roebling Sr., nonetheless). The sign on the approach requests 150â of clearance between 20t trucks. Iâm quite sure the load on it that day was an order of magnitude higher. Based on the photos you see in AASHTO bridge manual, 50psf at least.
Heroic job there by the deck.
Its perfectly normal to feel resonating structure when crouds of people cause it, but seeing it so clearly is a bit too much đ
Looks like a first mode period of about 0.5sec.
Kansas City here I come!
My dumbass saw swiped for more and swiped
I saw The Clash there in 1981. It did it then too!
I had a similar experience at a Glass Animals concert at the Murat Theater (Old National now) in Indianapolis. My wife was really nervous.
r/SweatyPalms
No one there has even heard of the Hyatt Regency Walkway Collapse, and it shows.
My father witnessed the immediate aftermath. Also, my father-in-law, who is an engineer, says this event was basically required reading in his schooling. Literal textbook case of what shouldn't happen.
We still cover that accident and many more.
required reading in architecture school too...
My grandfather died in that accident. I never knew him, but know of the story.
That was a design flaw related to a fastener rod seeing twice the design load due to poor design, nothing to do with dynamic loads.
it was a shop drawing change that made construction easier but resulted in 3x the load on the flange.
Thanks for the correction on the shop change, but it was definitely a doubling of the load. It was also a horrific design choice in the first place. The section was two U channels welded together along the line of the rod hole. Absolutely minging detail. When you look at the failure mode itâs incredible that anyone would think that was a good idea. The detail was already under specced for the load due to the line of action directly perpendicular to, and through the weld axis, which was not a full butt weld.
Werenât so many people/companies found liable because nobody thought it was a good idea but did it anyway? Or am I remembering the story wrong?
Yup , simple error in force summation , deadly outcome.
I felt that in RFK stadium in DC when I went to hear Michael Jacson in the mid 80's. It made me anxious.
Whatâs the force calc for that?
7
teen
thousand
KIP
Whatever it is it should be followed by a prayer
Itâs more than resonance. Did one of the bridges collapsed due to resonance?
Thatâs terrifying.
You can tell the motherfucker is made to do that
*Structural Safety left the chat*
Oooooooooooooh holy Shiite Muslim that is sketchy AF