Building collapse from one floor removal IDENTICAL FREEFALL to WTC tower collapse.

Originally posted by Azp420
Incorrect. The typical compressive strength of even low grade structural steel is over ten times that of structural concrete.

Thank you for chiming in with your expertise. These trusters will make up anything, or cling to any fantasy they can so as not to have to entertain any alternate theory besides the official theory.

It really makes you wonder what school or training teaches some of these people the things they type on their screen. Or are they typing these things (such as concrete stronger than steel! ) out of fear and denial of what the real truth might be? Hopefully not too much more time will tell.

Originally posted by _BoneZ_

Originally posted by Azp420
Incorrect. The typical compressive strength of even low grade structural steel is over ten times that of structural concrete.

Thank you for chiming in with your expertise. These trusters will make up anything, or cling to any fantasy they can so as not to have to entertain any alternate theory besides the official theory.

It really makes you wonder what school or training teaches some of these people the things they type on their screen. Or are they typing these things (such as concrete stronger than steel!

) out of fear and denial of what the real truth might be? Hopefully not too much more time will tell.

edit on 16-2-2011 by _BoneZ_ because: (no reason given)

You still on about this strawman argument?

Here is my post that was taken out of context.

No, that is not true. The reason buildings are made of steel in earthquake prone areas is because they are designed to flex and move. They have much better ability to move laterally than concrete.

Where do you get that I said steel buildings are stronger than concrete?

Nowhere.

I also said that concrete's compression strength mainly comes from the steel in the concrete.

So, you gonna keep going with the strawman?

reply to post by FDNY343

Where do you get that I said steel buildings are stronger than concrete?

Nowhere.

I also said that concrete's compression strength mainly comes from the steel in the concrete.

From this post:

But, concrete has a better compression strength

In any case the point is moot. The OP's video is like comparing apples and oranges. The video also does not show a wave of collapse accelerating towards the ground at anywhere near ~2/3rds g. I didn't look too closely but I doubt it is even accelerating.

Originally posted by Azp420
reply to post by FDNY343

 

Where do you get that I said steel buildings are stronger than concrete?

Nowhere.

I also said that concrete's compression strength mainly comes from the steel in the concrete.

From this post:

But, concrete has a better compression strength

In any case the point is moot. The OP's video is like comparing apples and oranges. The video also does not show a wave of collapse accelerating towards the ground at anywhere near ~2/3rds g. I didn't look too closely but I doubt it is even accelerating.

Which is a STRAWMAN. I even EXPLAINED it in the post that you QUOTED me with!!

And like I said, steel has a better ability to withstand LATERAL loads. This is due to the ductility of steel.

See here.

Steel’s strength and ductility, combined with solid engineering and design, make it a safe choice in seismic zones. “Steel framing does very well under high [wind] loads because it is ductile, which means it has the ability to bend without breaking and can absorb that kind of energy,” says Larry Williams, president of the Washington, D.C.-based Steel Framing Alliance, of cold-formed steel.

www.buildings.com...

reply to post by FDNY343


You said in your post that concrete has "better" compressive strength than steel. This is incorrect and I pointed it out to you. Instead of acknowledging your mistake and moving on you continue to argue it to the death, claiming STRAWMAN every chance you get.

And like I said, steel has a better ability to withstand LATERAL loads. This is due to the ductility of steel.

Don't try to school me on building mechanics, it is clear you are in over your head, fireman (and I can see why the OS seems plausible to you).

The reason steel has a better ability to withstand all types of loads is because it has much higher yield strengths. A continuously braced steel column and concrete column of equal length and shear/bending design strength will both have the EXACT same ability to withstand lateral loads.

The reason ductile structures perform better than rigid structures under CYCLIC lateral loading (what I assume you are trying to refer to) is because they only have to withstand smaller internal loads! This is mainly because (depending on the external load conditions) the period of vibration is greater in the ductile structure, giving it more time to absorb the energy, resulting in a lower peak load spread out over a greater time, compared with a higher peak load spread out over a smaller time in the rigid structure.

reply to post by Azp420

It is a common problem today. It seems many young people want to be an authority on something, without paying the dues required to be that authority.
When I was young, it was regularly pointed out to me that I had a long way to go before I could teach class. But, it was also pointed out that classroom teachers are often only good at being classroom teachers. Nothing against teachers, of course.
The lesson was simple, nonetheless. Do your "homework", and LISTEN...LEARN. You JUST might be able to see what others miss. Being smacked around a bit by the older folks for speaking out of turn is apparently a lost art...not practiced much anymore.
Shame.

reply to post by Azp420


Well as a structural engineer have you any comments on the collapse seen here from 2:30 on this video.




What do you see happen and whats your take on it!

Why is that video edited RIGHT BEFORE THE COLLAPSE??? What crucial information did they remove?

Secondly, that's a concrete building - it has no steel inner core. That building is basically a house of cards, much like your argument.

Originally posted by harrytuttle
Why is that video edited RIGHT BEFORE THE COLLAPSE??? What crucial information did they remove?

Secondly, that's a concrete building - it has no steel inner core. That building is basically a house of cards, much like your argument.

They are trying to show the principle of a pancake collapse thats the point of the op video its just to show its possible!

Quote by boney z...
" Or are they typing these things (such as concrete stronger than steel! ) out of fear and denial of what the real truth might be? Hopefully not too much more time will tell."


He didn't actually say concrete is stronger than steel, and its hardly a moot point... its you completely changing what he said to suit your own point of view.

I recently saw a top down demolition video (from France i think) and the buildings are supposedly steel frame and the effects are exactly the same as the other videos i posted, which, as you haven't acknowledged, show a remarkable similarity to the Twin Towers collapse.

I am looking for that vid and will post when found.

Would you at least agree they (the vids here and the WTC towers collapses) portray similar characteristics? As in the seemingly 'freefall' speed and pulverisation (billowing clouds...heavy debris thrown far... what looks like puffs of smokes from collapsing floors... etc etc).



Here it is... apparantly (says the internet) this was a steel frame building. Pulverised due to top down collapse.

reply to post by manmental

It can't happen. There is simply not enough downward pressure for a steel framed building to collapse based upon the weight of the upper floors without taking out the supporting vertical columns.
Unless said columns are "compromised" by explosives...or rust or some other form of deterioration.
You have bad information.

reply to post by manmental


I see what you are getting at but look at the location of each demolition. Exactly @half way or in the middle of each structure.

You have equivalent weight ie half the structure now being supported by the accelerated mass of the upper portion of the building.

Remember the free body diagram in physics ? Everything is subjected to equal and opposing forces.
The Normal as it is termed in Physics is the Force pushing up against the forces of the gravitational induced mass of the structure pushing downwards.

In order for anything to stand against the force of gravity it's Normal needs to exceed that of the gravitational mass of the structure itself.

The Normal is the cumulative summation of the forces provided by each floor of the structure itself.

By removing one support member of any structure, you are naturally inducing the portions of the structure above it to fall by weakening it.

The Normal or the forces of the remaining floors pushing upwards would be required to exceed that in order to crush the floors of the structure below.

Which is why in each of these examples the floors in the middle of the building are being removed vs the top.
The engineers calculated the stress loads on the floors below and knew how much stress they could support before collapsing.
A quick guesstimate would be to break the building into half.

The WTC had many more floors below to support. the floors above that had collapsed.
So the numbers just don't add up.

Also, if this truly was a gravitational collapse. What would necessitate to have not only removed the evidence (ie steel beams) from the crime scene but also to have it shipped to China ?
And the "missing" black boxes ?

Can you say "Cover Up" ?

it collapsed in 4 seconds, the wtc towers were a lot taller and collapsed in just under 10, so even if we are conservative and say the wtc is 4 times as tall, the collapse would have taken 16 seconds. That building does not have a steele column either and the collapse does not sound like a torrent of explosions as well.