Concrete inner core using some calculations

[Gamolon]

Ok, I'm doing some math here, so follow along and see if there are mistakes and or variables I am missing.

One of the tower's estimated total weight was 500,000 tons. 100,000 tons of it was structural steel leaving 400,000 tons for other materials. I have some dimensions given to me from Christophera saying that the inner core's two smaller walls were 17ft thick at the base, 2ft thick at the top and about 87ft long

I calculated one of these walls (wedge shaped) to be 1,130,652 cubic ft in volume. I took out the space that the 3" diameter rebar from top to bottom would have taken up. I used his 4' on center measurements for the rebar. I used a rectangle of 17ft x 87ft x 1368 ft to calculate the area taken up by rebar instead of the proposed wedge shape of Christophera's wall just to make it easier on me. The volume of the wall is actually more than what I propose.

I then used 148lbs per cubic ft for concrete (limestone/Portland mix) and came up with 167,336,496 lbs. or 83,668 tons of concrete for one wall. For two walls I get 167,336 tons.

So, what we have so far is 500,000 tons total for one tower minus 100,000 tons of steel, leaving 400,000 to play with. Now, subtract 167,336 tons to get 232,664 tons left.

I then came up with about 740 tons per concrete floor. I used 208ft x 208ft x .333ft (4 "). I then subtracted out the center taken up by the core. I got 10,002.69 cubic ft. Multiply that by 148 lbs. per cubic ft and you get 1,480,438.08 lbs. or 740.21 tons. I'm not sure about rebar displacement so I will use 700 tons per floor. 700 tons x 110 floors equals 77,000 tons.

232,664 tons from above minus 77,000 tons for the floors and we get 155,664 tons left.

We haven't even calculated the the other two, longer walls he is proposing nor are we yet calculating the two interior walls of the core he shows on his website.

Am I calculating this right? I've also seen totals of concrete used ranging from 90,000 tons to 110,000 tons.

Also, why would architects use a continuous wall of concrete of that thickness when the building would sway 3 ft.? Wouldn't this subject the concrete core stress fractures? I have also read that the towers were built to be lightweight because of their height. Why would an architect use the concrete structure proposed by Christophera?

Thoughts?

[Gravy]

100,000 tons of steel per tower.

ETA: Other than that, why spend time trying to parse Christophera's delusions?

[uk_dave]

I have some dimensions given to me from Christophera saying that the inner core's two smaller walls were 17ft thick at the base, 2ft thick at the top and about 87ft long



What did they build? A castle?

[T.A.M.]

if the walls were 17 feet thick, I do not think even an ICBM would have caused them to collapse...

lol
TAM

[CurtC]

Thoughts?Yes - why are you trying to engage in a factual debate with Christophera?

[Crazycowbob]

What did they build? A castle?

No no no, they were clearly building a Dam to direct the exlosives and keep all the debri inside the towers footprint, isn't that obvious?
:D

[Architect]

Just as a matter of interest, do we have a definitive source for the 500k ton(nes) anywhere? I'm debating this (amongst other things) with a CT clown over at Urban 75 and he plucked the figure out of the air. I'm aware it's widely quoted, but I couldn't find a calculation to back it up.

[Arus808]

if the walls were 17 feet thick, I do not think even an ICBM would have caused them to collapse...

lol
TAM


Considering that Nuclear Power Plants have walls (reinforced concrete) that are no thicker than 3 meters.....Even that ever famous test that we use, the concrete wall is 3 meters...if it can pulverize a plane into pieces...

[Gamolon]

Just as a matter of interest, do we have a definitive source for the 500k ton(nes) anywhere? I'm debating this (amongst other things) with a CT clown over at Urban 75 and he plucked the figure out of the air. I'm aware it's widely quoted, but I couldn't find a calculation to back it up.

No definitive source from my end. Like you, I've just seen it stated in various articles concerned with the construction.

As far as why do I continue to confront Christophera, I like to debate. I figured I haven't seen anyone present this argument to him before so I thought, "what the heck".

The problem I have is that he uses pictures that are either blurry, clouded with dust and smoke, or taken from a great distance. He uses these pictures as factual evidence to prove what he claims to be there. My point in all of this is if I were to take his pictures and ask an engineer what he sees, I'm sure that he wouldn't come right out and say "concrete core" and 3" diameter rebar. Just as i wouldn't expect him to say there was steel beams. You just can't see that level of detail in Christphera's photos. They prove nothing.

There are other, more detailed photos that clearly show the structural steel of the inner core, yet he has problems producing those same quality pictures of his concrete inner core. I can find tons of pictures taken during construction that show everything clearly, but I fail to see any indication of the construction of a concrete core. No wood forms being built, no concrete being poured into the core, nothing. Videos make no mention of the concrete core either.

All he shows are a few unconvincing photos and a documentary that "mysteriously" is gone.

How can a human being determine that he is looking at a piece of 3" diameter rebar in a photo that was taken from 7500 ft. away? Impossible.

[uk_dave]

Yeah well...Christophera has...... issues.

[The Almond]

As far as why do I continue to confront Christophera, I like to debate. I figured I haven't seen anyone present this argument to him before so I thought, "what the heck".


I did a full out structural analysis of a 17 ft thick shear wall with 3 inch diameter rebar (which does not exist, rebar goes from size 3 to size 18 with size 18 being 9/4 inches in diameter) and showed that the wind load for a building that size would have to be nearly 2000 mph for such a shear wall to be necessary.

Presented with the facts, I asked Christophera to reconcile his analysis with an actual structural calculation. He replied that it wasn't his job to reconcile his "facts" with my "math." At that point, I realized that I was dealing with a delusional person and I quit the thread.

[Architect]

No definitive source from my end. Like you, I've just seen it stated in various articles concerned with the construction.


I've given it a good google (yeah, yeah, I know that's not real research) and can't find a calculation. A skeptic on another site posted this, which I thought rather interesting.

I have never seen a detailed calculation of the mass of WTC 1 or 2, although the design engineers would undoubtedly have made such calculations. There are plenty of references on the web for the weight of the materials used in the construction of the WTC Towers. For example, the weight of structural steel used in each Tower is generally reported to be 96,000,000 kg and the weight of concrete is said to be 48,000,000 kg per Tower. I have also seen the weight of aluminum cladding reported to be 2,000,000 kg, and the weight of wallboard quoted at 8,000,000 kg per Tower, giving a total weight of structural materials of 154,000,000 kg per Tower.

Now let’s add in reasonable “guesstimates” for plumbing fixtures (5,000,000, kg), air conditioning (5,000,000 kg), electrical and telecommunication wiring (5,000,000 kg) and we have an additional 15,000,000 kg of structural mass that civil engineers always include as part of the “dead load” of a building. Thus combining all these contributions, we arrive at a weight, or dead load, of 169,000,000 kg for one WTC Tower. Surprisingly this accounts for only about 1/3rd of the oft-quoted 500,000,000 kg, so where is the missing mass?

The answer would appear to be in what we call the live load of the building, which in the case of one WTC Tower would have to be (500,000,000 - 169,000,000) kg or 331,000,000 kg, i.e., twice the dead load! We will show that this result leads to major problems …..

But first, let’s convert our load data in to more familiar engineering units based on floor areas. Building regulations usually express loads in kilograms per square meter (kg/m^2) or Newtons. For example, the specification for a high live load capacity floor is typically about 750 kg/m^2.

From the dimensions of a WTC Tower we estimate the available floor area per Tower was about 320,000 square metres. Hence, the live load was 331,000,000 kg divided by 320,000 m^2 which is equal to 1034 kg/m^2. We see from the live load example given in the previous paragraph represents a very high live loading. But let’s look at just how high this load is…..

If the live loading within one WTC Tower really was 331,000,000 kg (more or less), that equals 3,009,091 kg per floor or about 3000 tonnes per floor!! If we say that each WTC Tower employed about 15,000 people so we have an average of 136 people per floor. This means that each person working in the Twin Towers contributed about 22 tonnes of live load!!! That's an awful lot of office furniture, computers, printers, telephones..... or am I missing something?

Now if we look on the web, we find the following weights for other tall buildings - note, in passing, that these employed pro-rata heavier traditional structures than WTC:

Empire State Building, NYC = 365,000,000 kg
Woolworth Building, NYC = 223,000,000 kg
John Hancock Tower, Chicago = 174,500,000 kg

Anywne want to weigh in (pun intended)?

[Gamolon]

100,000 tons of steel per tower.

ETA: Other than that, why spend time trying to parse Christophera's delusions?

Thanks for the correction Gravy. I took 200,000 for one tower. I will correct my post to reflect this.

[Gamolon]

Just as a matter of interest, do we have a definitive source for the 500k ton(nes) anywhere? I'm debating this (amongst other things) with a CT clown over at Urban 75 and he plucked the figure out of the air. I'm aware it's widely quoted, but I couldn't find a calculation to back it up.

I found this:

http://forum.physorg.com/What-was-the-weight-of-a-WTC-Tower_4299.html

May be of interest.

[Architect]

I found this:

http://forum.physorg.com/What-was-the-weight-of-a-WTC-Tower_4299.html

May be of interest.

Yup, same poster used the one I give above but in metric only.

But there has to be a better calculation somewhere. I don't recall one in the NIST report, but that could be the effects of all the co-codomol....

[Gamolon]

I did a full out structural analysis of a 17 ft thick shear wall with 3 inch diameter rebar (which does not exist, rebar goes from size 3 to size 18 with size 18 being 9/4 inches in diameter) and showed that the wind load for a building that size would have to be nearly 2000 mph for such a shear wall to be necessary.

Presented with the facts, I asked Christophera to reconcile his analysis with an actual structural calculation. He replied that it wasn't his job to reconcile his "facts" with my "math." At that point, I realized that I was dealing with a delusional person and I quit the thread.

Funny that. He's bold enough to post things as "facts" and expects us to believe him in blind faith without proving a thing. The 3" diameter rebar not existing was another question I had. I couldn't find it for the life of me listed anywhere. Even (ASME?) handbooks don't list it.

[Gravy]

Gamolon, Chris is ill and is not responsive to reason about this issue. Yes, your argument has been presented to him in the past. If you choose to "debate" him, you will only frustrate yourself. Please don't encourage his behavior.

[Architect]

You don't get 75mm reinforcing bar, for a start. The joints and connections would be too hard to form. Instead you'd increase the amount of normal sizes.

[uk_dave]

Funny that. He's bold enough to post things as "facts" and expects us to believe him in blind faith without proving a thing. The 3" diameter rebar not existing was another question I had. I couldn't find it for the life of me listed anywhere. Even (ASME?) handbooks don't list it.

I'd love to see a bending schedule for 3" rebar

[defaultdotxbe]

Funny that. He's bold enough to post things as "facts" and expects us to believe him in blind faith without proving a thing. The 3" diameter rebar not existing was another question I had. I couldn't find it for the life of me listed anywhere. Even (ASME?) handbooks don't list it.
yeah, it hink chris's position is that it was custom fabricated

[Gamolon]

Gamolon, Chris is ill and is not responsive to reason about this issue. Yes, your argument has been presented to him in the past. If you choose to "debate" him, you will only frustrate yourself. Please don't encourage his behavior.

LMAO!

I like you Gravy. You sound just like my dad. He'd say the same thing.

:D

[CurtC]

Gamolon, not only is debating with Christophera frustrating to you, it's cruel to him. Please just let him be - he's a sick person. You wouldn't go down to the bus station and try to debate the crazy people there, would you? This is the same thing, the only difference is it's done over the Internet. These people deserve our trying to help them, not taunting them.

[Gravy]

LMAO!

I like you Gravy. You sound just like my dad. He'd say the same thing.

:DYou're new here and I can understand your thinking that I was kidding. I wasn't. Chris has a serious problem (http://www.angelfire.com/ca5/nojustice/timeline.html)and we're not going to help him by engaging with his delusions.

[The Almond]

You don't get 75mm reinforcing bar, for a start. The joints and connections would be too hard to form. Instead you'd increase the amount of normal sizes.

I remember making this point to Christophera, too. If you need 9 in^2 of steel, you don't put one 3 inch piece of rebar, you put 3 1 inch pieces (#9) and space them at 3/4 of the nominal maximum aggregate size for concrete.

[c6gunner]

You're new here and I can understand your thinking that I was kidding. I wasn't. Chris has a serious problem (http://www.angelfire.com/ca5/nojustice/timeline.html)and we're not going to help him by engaging with his delusions.

Wow. In his case, "Serious Problem" is a serious understatement.