four foot rebar? What are you talking about?
How the WTC Core Supports Weakened.
- Thread starter SBrown
- Start date
four foot rebar? What are you talking about?
That's about it. I loathe so-called neo-conservatism as much as most, and am appalled by construction fraud, but there just ain't nothin' here to get indignant at.
Except the woos playing on honorable people's graves.
I guess you are not aware that the towers were designed to support six times the load that they supported (four times was the code at the time). Of course they easily did this and redistributed their weight as they were designed. Using pasta as an example is just ludicrous.
SBrown, what is your level of understanding of structural engineering? Training -- formal, informal?
[edit] I ask because others who know far more about this sort of thing than I do will want to know how much you already know, so as not to repeat things you already understand. You'll want to know your stuff, because some of the people here work with this sort of thing day in and day out, and will find the errors in flawed arguments before you can say "boo."
[edit] I ask because others who know far more about this sort of thing than I do will want to know how much you already know, so as not to repeat things you already understand. You'll want to know your stuff, because some of the people here work with this sort of thing day in and day out, and will find the errors in flawed arguments before you can say "boo."
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I've been keeping up with all the arguments and that's really what irks me as a lurker. There's no (good) reason to do what the CT's do. I understand there's a certain psychology to it but for the love of Bob... I don't know anyone who wasn't a degree separated from the tragedy. It leaves marks and these guys seem to be using their patented CT Whiteout (gets the joooos out!) to re-write history.
I thank a random deity every time I meet an average person who doesn't think the CT's are worth a listen. Every rational mind keeps us further away from insanity as a nation (world).
Rebar is used to reinforce concrete.
The WTC's had 47 four foot thick steel colunms that ran the entire lenght of the building throught the core. Take a look at the picture I posted.
Gravy
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Oh, Noooooooooooooooooo!
The Law of Conservation of Christophera
In an internet forum, Christophera is neither created nor destroyed.
In an internet forum, Christophera is neither created nor destroyed.
You do a darned fine job too. Better than I do certainly. Which is why I keep my big mouth shut most of the time. Wouldn't want an angry skeptic to hurt those little CT feelings and ruin the "cause".
Gravy
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Are you claiming that there were columns of 4-foot-thick solid steel? Are you sure you don't mean 4-inches thick?
Made me think of the anecdote about Thomas Edison (IIRC) and the cubic foot of copper.
gumboot
lorcutus.tolere
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I think it should be pointed out...
The 47 core columns were not single lengths that ran the entire way from the foundations to the top of the buildings. There were a series of columns (can someone confirm their length?) bolted together in sections. Hence why they broke apart the way they did - the forces of the collapse undermined the bolts holding each section.
If they single continuous columns, yes, your concerns would be valid. However they were not.
Think of it like a lego building. If you smash a lego building it is highly likely you will not actually break any of the lego pieces. However those pieces will break apart from each other. A great deal (though not all) of the WTC's steel collapse appears to be disintegration into componant steel elements.
-Andrew
The 47 core columns were not single lengths that ran the entire way from the foundations to the top of the buildings. There were a series of columns (can someone confirm their length?) bolted together in sections. Hence why they broke apart the way they did - the forces of the collapse undermined the bolts holding each section.
If they single continuous columns, yes, your concerns would be valid. However they were not.
Think of it like a lego building. If you smash a lego building it is highly likely you will not actually break any of the lego pieces. However those pieces will break apart from each other. A great deal (though not all) of the WTC's steel collapse appears to be disintegration into componant steel elements.
-Andrew
Gravy
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A continuous column will still buckle when it exceeds its carrying capacity, though. A 1368-foot single-piece WTC column would still need all that lateral support.
gumboot
lorcutus.tolere
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I thought I would share something interesting about high-rises.
The heat output in high rise office buildings in most of the western world has increased by a factor of 6 in the last thirty years.
This is for two reasons.
Previously, a single person would be allocated an office space. Now that same office space (on average) is occupied by three people.
The second reason is that now each of these three people has a desktop computer (as opposed to a desk and some pens and paper).
A desktop computer (on average) gives the same heat output as one person.
Thus the factor of six increase in heat output.
This is interesting, because it also relates to load. Not only are three times as many people working in a given high-rise (on average) but this results in an increase in overall load weight. Everyone has a computer. Three-times as many desks. Three times as many wastebaskets. Three times as many bathrooms. Three times as many water-coolers, and so forth...
Add to that the additional air conditioning system required to deal with 6x the internal heat production of the original design, and you have a considerable increase in occupancy load on the structure, compared with at the time of design.
So a load redundancy factor of 6 at design, becomes a lot lower in 2001.
In addition to that, a redundancy is based on constant load. Such factors do not take into acount a quarter of the building collapsing through four destroyed floors onto the rest of the building at 9.8ms^2.
Lastly, the design of a building like the WTC relied on overall structural integrity because load was carried by the complete structure - not just by a central element. The aircraft impact disrupted all three elements of the building's structure at once - the exterior columns, the core, and the floor trusses. The fires continued to undermine all three elements across the area of impact and above.
None of these are things that are taken into account in building design.
-Andrew
You should know by now the answer to that is 'just one more time', every time.