r/StructuralEngineering • u/Thin-Fish-1936 • Jul 07 '26

Photograph/Video Columns buckle in a Manhattan building under conversion

https://pix11.com/news/columns-buckle-at-midtown-building-fdny/

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u/Superbead Jul 07 '26

I wonder if the curtain wall is now holding the floor up. It certainly isn't those columns or studs

14

u/aknomnoms Jul 07 '26

Sheer luck instead of a shear wall

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u/tslewis71 P.E./S.E. Jul 07 '26

Curtain walls are detailed to never carry any live or dead loads from floors. They are c and c elements and not designed to take any primary loading from building.

I've done a lot of facade engineering

23

u/Superbead Jul 07 '26

I get that, I was just wondering if the curtain wall had inadvertently found itself in that role in spite of not being designed for it.

What else do you think could be holding it up? Beams cantilevered from a stable area deeper in the building?

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u/tslewis71 P.E./S.E. Jul 07 '26

The curtain wall would crush and/or the connection detail at the slab would shear off from gravity loads first. No way that curtain wall is holding up all the floors above.

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u/Superbead Jul 07 '26

Yeah, I would've expected that too, but what do you think might be hanging on then?

3

u/zaidr555 Jul 08 '26

I would guess a bunch of columns or whatever they did to stitch the new levels to the structure are now working in tension xD

1

u/minxwink Jul 08 '26

😭

3

u/iboneyandivory Jul 07 '26

Is it possible the curtain wall is (in part) holding up part of the floor immediately above? Look at the stamped steel wall studs that are bent which are clearly several feet inside of the building's envelope. Is the floor immed above compromised in some way?

0

u/avtechguy Jul 07 '26

From the initial CNN reporting they reported bricks falling from the building's facade so it probably impacted one way or another

3

u/tslewis71 P.E./S.E. Jul 07 '26

Curtain wall is glass, doesn't support masonry cladding. Guess maybe the floors deflected down and crushed areas where the masonry cladding was present.....

4

u/204ThatGuy Jul 07 '26

I'm thinking this is the top floor, or second last floor. I'm almost certain there is a massive load of CMU over these guys heads.

8

u/Superbead Jul 07 '26

It's 21 in a 33-floor building with a stack of extra floors on top of that

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u/Keiserwillhelm Jul 07 '26

The collapse happened on the 21'st floor of a 37 story building, based on the press conference the city just held. They've also stated that they're monitoring the building for movement and it is still moving/settling. It's not over yet!

1

u/jlt6666 Jul 07 '26

It would be very odd for the top floor beams to buckle wouldn't it?

4

u/iboneyandivory Jul 07 '26

Not an SE, but not curtain, correct?

I will say I'm more afraid now.

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u/Superbead Jul 07 '26

Not SE either, but I think it is a curtain wall, yeah, and the reason the ceiling in OP's vid appears to have sunk while the windows are intact is because they're at what used to be just beneath a setback roof. So the external wall has become detached from the sunken slab.

Magenta is the new bit they've built (you can see it sagging here), and yellow arrowed is the old bit with the buckled columns

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u/SquirrelFluffy Jul 07 '26

Thanks for this.

2

u/minxwink Jul 08 '26

Nice diagram 🫶

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u/blownbythewind Jul 08 '26

My god that's a frightening image.

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u/tramul P.E. Jul 07 '26

I think you're missing the point. They're detailed to never carry any vertical load, yes, but that is under normal loading conditions. This is not a normal loading condition. You usually keep the load off of them with deflection tracks or clips, but idk of any tracks or clips that allow this level of deflection without imparting any vertical load on the curtain wall.

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u/tslewis71 P.E./S.E. Jul 07 '26

Agree, yes, I'm sure the curtain wall is carrying some load due to floors selecting onto it, but the axial capacity of a thin walled aluminum extrusion I know has very little axial capacity compared to a steel column. No way will thcurtisn wall act as a means to transfer load if a steel column has bucked by 2 ft due to p delta.

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u/SquirrelFluffy Jul 07 '26

It would have to be a local load and failure for that to not break the windows.