Building under construction collapses in George

Spizz said:
Some of us actually do this for a living. And as discussed right throughout the thread, when you look at those columns and how the slab has separated from them, something isn’t right.

And FYI, my expertise doesn’t come from the Internet but from a university degree in civil engineering followed by 30 odd years of building schit like this.
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Yes! Thank you! That's exactly what I'm looking for.

So in your opinion, what do you think might be the cause for the separation? Obviously it's just speculation, but just your overall opinion. Concrete not setting?

Do you think it's a design flaw or construction flaw?

I'd love an an actual engineer's opinion that isn't as stupid and dumb as mine.
 
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genetic said:
Ok, so you're talking out of your ass, Mr. Rebar internet expert. Just needed the confirmation.
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Oh JC, so you have a small ego and now you have to storm onto an internet forum to pick a fight with a random stranger you know f-all about?

FWIW, doing a BSc Eng you learn a lot about a lot of things before you complete your degree, which for me was ~40 yrs ago. If there are folks about that knew him, they'll tell you who Prof GT van Rooyen was. So, yes I may comment on certain materials ... but as as I also said, do that phone a friend.

So put that in "your ass" and look for shyt elsewhere.
 
genetic said:
Yes! Thank you! That's exactly what I'm looking for.

So in your opinion, what do you think might be the cause for the separation? Obviously it's just speculation, but just your overall opinion. Concrete not setting?

Do you think it's a design flaw or construction flaw?

I'd love an an actual engineer's opinion that isn't as stupid and dumb as mine.
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I’ve had a few whiskies, so here’s a post from early on in the thread and there’s also a few follow ups after this one with further explanation.

Spizz said:
Civil engineer here, I've built many multistorey constructions, including some big offices in CT that maybe some of you are sitting in reading this.

First thoughts looking at the one picture are that the columns do not appear to have rebar at angle to tie into the floor at 90 degrees, so in essence, the floors have punched through them. From the pic the rebar is straight up and the floor is detached. Should be like this...

View attachment 1704739

So the building looks like it's pancaked and the columns designed to hold the floors have been useless in stopping the loads bearing down on it. First thought again is this could be due to the floors not being given enough time to cure properly, so not reaching design strength and crucially, also not being supported properly during the time it takes to cure.

The formwork for the top floor needs to obviously be propped when the concrete is poured onto it. What is not always understood is what happens to the floors below. For example, and putting it simply, if the 4th floor has 100% props, third floor needs to have 50% props and second floor has to have 25% props. This is to distribute the loads through the floors and down the columns and down to the ground.

So if the 4th floor is cast and the 3rd floor has not reached sufficient strength and the props are not distributed properly or even removed, then this could lead to the loads being unevenly distributed and considering the columns don't appear to be supporting the floors, then this whole thing pancakes out one floor on top of the other.

I've had several near misses with people removing props because they don't understand the process, sometimes even during casting the top deck, someone two floors below has moved props hat get in their way.

Anyway, just a guess going on the one picture.
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Koning Witou Solomon said:
Oh JC, so you have a small ego and now you have to storm onto an internet forum to pick a fight with a random stranger you know f-all about?

FWIW, doing a BSc Eng you learn a lot about a lot of things before you complete your degree, which for me was ~40 yrs ago. If there are folks about that knew him, they'll tell you who Prof GT van Rooyen was. So, yes I may comment on certain materials ... but as as I also said, do that phone a friend on.

So put that in "your ass" and look for shyt elsewhere.
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Dude calm down, all I asked for was YOUR opinion on why you thought the rebar didn't look right, and here you are, still not answering my question. I'm asking an opinion from you - that's all. You're quick to claim the rebar isn't right, but you get nasty when I ask why. Typical internet "expert"
 
So if the 4th floor is cast and the 3rd floor has not reached sufficient strength and the props are not distributed properly or even removed, then this could lead to the loads being unevenly distributed and considering the columns don't appear to be supporting the floors, then this whole thing pancakes out one floor on top of the other.

I've had several near misses with people removing props because they don't understand the process, sometimes even during casting the top deck, someone two floors below has moved props hat get in their way.
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This was exactly the answer I was looking for. @Spizz Thank you! :)
 
genetic said:
Thank you!
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I talked more about the rebar in another post somewhere. But basically, that column standing there isolated and pointing to the sky is very suspicious. There should be a lot or rebar surrounding the top of that column and the fact that the slab has moved off of it and landed several meters away means they weren’t tied in properly. Again, all based on one or two grainy pictures.
 
genetic said:
Dude calm down, all I asked for was YOUR opinion on why you thought the rebar didn't look right, and here you are, still not answering my question. I'm asking an opinion from you - that's all. You're quick to claim the rebar isn't right, but you get nasty when I ask why. Typical internet "expert"
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Huh? You have a strange way of asking, look at what you posted below.
genetic said:
OMG, here come the highly qualified engineer internet experts. You have clearly done your expert calculations. I'll forward your details onto the television news networks so you can give your expert opinion.
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Work on your communications skills dude.

This thread has been hijacked to death already by folks trying to abuse a tragedy.
 
Spizz said:
I talked more about the rebar in another post somewhere. But basically, that column standing there isolated and pointing to the sky is very suspicious. There should be a lot or rebar surrounding the top of that column and the fact that the slab has moved off of it and landed several meters away means they weren’t tied in properly. Again, all based on one or two grainy pictures.
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Yeah it's all speculation right now I guess, but your explanation comes from an educated space, so thank you!
 
Koning Witou Solomon said:
Huh? You have a strange way of asking, look at what you posted below.

Work on your communications skills dude.

This thread has been hijacked to death already by folks trying to abuse a tragedy.
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You are 100% right. My bad - I shouldn't have accused you immediately like that. I jumped the gun there, so my apologies.
 
Spizz said:
I’ve had a few whiskies, so here’s a post from early on in the thread and there’s also a few follow ups after this one with further explanation.
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I did see some photos with the rebar bent that way

We also don't know what was cut to remove from site

Working with reinforcing getting it like an engineer designs does take some thinking

Especially where one element intersects with another

Years of experience make that easier but first time round

You think now how does he expect me to finish with it looking like that

So can imagine that those with little experience end with spare pieces
 
genetic said:
No really? I'm seriously interested! What about the rebar is sketchy? And what about my reading skills is bad? Please enlighten me on both. You mentioned the amount of rebar in the columns looked insufficient, and I want to know why you said that?

Were you referencing horizontal or lateral forces? What is the standard amount of rebar used considering the type of rebar used for the horizontal and lateral forces exerted on the structure? Or did they used an inferior and untreated carbon steel instead of stainless steel? Were the joints maybe bad? Lack of epoxy coating?

I'm not an engineer at all, so really want to hear your opinion. And I'm not singling you out at all. @buka001 can add his weight in too. You guys seem to be the experts.
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The detail at the top of the column, where it connected to the slab looks suspect.

As I said it appears to have lacked sufficient development depth into the slab.

Typical detail at those connections will have L-shaped bars with several shear links. Or at least quite long straight bars projecting through the slab to the wall or column above.

I only see short straight bars.

Some typical details of a slab to column connection
 

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Koning Witou Solomon said:
Oh JC, so you have a small ego and now you have to storm onto an internet forum to pick a fight with a random stranger you know f-all about?

FWIW, doing a BSc Eng you learn a lot about a lot of things before you complete your degree, which for me was ~40 yrs ago. If there are folks about that knew him, they'll tell you who Prof GT van Rooyen was. So, yes I may comment on certain materials ... but as as I also said, do that phone a friend.

So put that in "your ass" and look for shyt elsewhere.
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out of interest do you keep your ecsa number up to date as active or like so many dont bother any more ?
 
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