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video: balcony at mexican nightclub collapses, three confirmed dead


Derka

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12 hours ago, Deej said:

So, just like Texas beginning next year. 

The risk tolerance between cultures is WAY different.

People in the US will take their car into the shop when one of the radio buttons doesn't light up.

People in Mexico will drive with old towels taped around a burst tire and kids in an open trunk.

In the US you get fined for having the wrong color tail light. 

In Mexico you can make unlimited dangerous/insane mods to your car and no one says shit about it.

Mexican truck drivers install rear facing high beam spotlights to blind drivers behind them. I was driving from Puebla to Villahermosa behind some old POS rig that was driving about 30 and blocking both lanes. I gave him a quick high beam flash, then he fucking blinded me with his rear high beams and I nearly crashed. Shit there is fucking insane.

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1 hour ago, jimmyjazz said:

Yup, that was the GC who did that.  My dad headed up the structural engineering group (Civil) at Missouri-Rolla at the time, and he got brought in to consult on the post mortem.  The contractor had changed some of the joint designs and ultimately the natural frequency of the structure ended up aligning almost perfectly with the dancing going on.  It all started to oscillate (think Verrazano Narrows Bridge failure) and eventually came down.  It was  horrible.

Not trying to be a dick, but no, it was poorly designed and then changed to be an even worse engineering failure. 
 

watch that video I posted above

 

from wiki:

The original design by Jack D. Gillum and Associates specified three pairs of rods running from the second-floor walkway to the ceiling, passing through the beams of the fourth-floor walkway, with a nut at the middle of each tie rod tightened up to the bottom of the fourth-floor walkway, and a nut at the bottom of each tie rod tightened up to the bottom of the second-floor walkway. Even this original design supported only 60% of the minimum load required by Kansas City building codes.


This design change would be fatal. In the original design, the beams of the fourth-floor walkway had to support only the weight of the fourth-floor walkway, with the weight of the second-floor walkway supported completely by the rods. In the revised design, however, the fourth-floor beams supported both the fourth- and second-floor walkways, but were strong enough only for 30% of that load.

Jack D. Gillum would later reflect that the design flaw was so obvious that "any first-year engineering student could figure it out," if only it had been checked.

 

The original design was very fucked up then the changes were proposed by the steel contractor and approved over the phone by the engineer. The dancing didn’t help but they weren’t hitting a natural frequency to cause the collapse the walkways were just totally fucked up and barely able to hold their own weight.


 

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32 minutes ago, rage-a-holic said:

The risk tolerance between cultures is WAY different.

I live in a neighborhood of that culture. The vehicles are already more than dangerous..

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2 minutes ago, Deej said:

I live in a neighborhood of that culture. The vehicles are already more than dangerous..

I get it, I just don't think Texas dropping the inspection requirement is gonna turn us into Mexico. People that drive shitty, dangerous cars never kept them inspected anyway.

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The number of bald tires shredding on the car in front  of you on the highway may change your mind. Plus, those fuckers are still charging us the inspection fee

 

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3 hours ago, Zeus said:

Well

Balcony load is 1.5x the adjacent area, it’s an assembly so it’s 100 psf so they would use 100 psf anyway since it’s not to exceed 100 psf. 
 

A person typically takes up 3 sf and weighs 150#. So you would think 100 psf is pretty conservative. You have some reductions for larger areas that may have been taken on girders but those were joists failing. 

In this case you have 2 - 400# cholas crammed into about 2sf so we are overloaded about 200%. Still, I would’ve expected enough redundancy and considering the deflection limits, enough strength to keep it from complete collapse like that. 
 

Probably built wrong or an engineer wasn’t even involved in the construction. 
 

Sad, this is shit that should only happen in 3rd world countries. 

Berkeley in 2015 - 6 dead 

https://en.m.wikipedia.org/wiki/Berkeley_balcony_collapse
 

Chicago in 2003 - 13 dead 

https://en.m.wikipedia.org/wiki/2003_Chicago_balcony_collapse

I am surprised it doesn’t happen more often  

 

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2 minutes ago, The Ace of Aces said:

Berkeley in 2015 - 6 dead 

https://en.m.wikipedia.org/wiki/Berkeley_balcony_collapse
 

Chicago in 2003 - 13 dead 

https://en.m.wikipedia.org/wiki/2003_Chicago_balcony_collapse

I am surprised it doesn’t happen more often  

 

Well hopefully if everyone is following the ASCE7 and building code at the end there’s a compounding safety factor that is happening. The deflection limits usually control and so you could be nowhere near failure on beams and joists. There’s a safety factor on top of those pretty conservative load minimum estimates built into the AISC and NDS and ACI for steel, wood, and concrete as well. 
 

The thing that gets me in construction is the things I catch during inspections, there’s not a bunch of inspections happening on some projects. 
 

Working a big school job right now and I will say certain school districts even have different levels of required inspections that are taking place. Typically I work hospitals and higher education and it’s standard practice there but some school districts just suck and do the bare minimum or less. Thank God I’m not on any of those anymore and my kiddos won’t be going to school there. 

 

28 minutes ago, jimmyjazz said:

Yes, wiki is the ultimate arbiter of engineering design.  It was absolutely a dynamic failure related to resonance.  I won't argue this any more, believe what you want to believe.

Actually the engineering is the ultimate arbiter. You said the GC blew it, which they did, but also the engineer definitely caused those deaths. Maybe you have the inside scoop from your dad about resonance but NIST didn’t say that was the cause. Is your Dad Ron Hamburger from SGH? 

pg. 229-232

image.thumb.png.95ccca1ad4d5f8d382acbbdc388fc727.png

image.thumb.png.044f2531f65835ff0f95e395b9c2f843.png
 

https://nvlpubs.nist.gov/nistpubs/Legacy/BSS/nbsbuildingscience143.pdf
 

Just watch that video it explains it pretty clearly, simple statics —


image.thumb.png.f705ab01898c299bab7574242ea2f43c.png

Tough way to learn but every structural engineer studies the engineering failures that happened at this walkway because it was so catastrophic. Most deaths due to structural failure in US history and all. 

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3 minutes ago, Zeus said:

Maybe you have the inside scoop from your dad about resonance but NIST didn’t say that was the cause. Is your Dad Ron Hamburger from SGH? 

No, as I said he was a structural engineering prof brought in to consult.

No doubt there are horrible design decisions made all the time.  His relation of the story to me -- and I was a mechanical engineering student at the time, not wholly incapable of understanding the statics and dynamics -- was that the net load capacity was capable of handling the party weight.  As you say, factors of safety are built in to those calculations.  

He once had to deal with a company that hired one of his worst students on a co-op semester, and this dumbass had put the rebar on the wrong side of a retaining wall (so the rebar wasn't taking the tensile load it was intended to take).  Shit definitely happens.  People still sign off.  When contractors fundamentally change designs, that's just a whole 'nother level of malfeasance.

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On 6/10/2024 at 9:24 PM, DaysOff said:


That's our KC layover hotel. You can still see the attachment points in the walls for the walkways.

yikes.

well, stay out of room 237.

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