Slender column long span beam structures are inherently unsafe

It seems that we might want a separate thread for Ford problems.

We are discussing buildings here not cars.

I am understanding this correctly? That you feel that buildings need to be built to standards that would prevent the loss of life if the building was damaged by fire? If so, do you extend that to homes as well?
 
It seems that we might want a separate thread for Ford problems.

So you want to debunk an accepted conspiracy to which Ford executives admitted and apologised for and unprecedented fines were levied as a warning to others for... sounds reasonable... go for it.

We are discussing buildings here not cars.

Yes let us try to keep it focused. But I would remind you, it was actually you who conflated the thread into cars etc.

I am understanding this correctly? That you feel that buildings need to be built to standards that would prevent the loss of life if the building was damaged by fire? If so, do you extend that to homes as well?

No, you are misunderstanding what I say. I am simply trying to establish why some buildings are able to withstand intense fires for protracted periods without collapse whilst WTC buildings conspicuously did not.

I am also suggesting that high rise and medium rise buildings, (anything over the height attainable by ladders), should be able to withstand very serious fire without collapsing as in particular, WTC7 did. I am also trying to ascertain, how many buildings are out there which are likely to collapse during an intense fire of more than 2 hrs?
 
I used cars as an example of the fact that most folks use a cost/risk assessment in choosing purchases for their family. YOU took it to a concrete example.

Let's try this one instead. I live in tornado alley. There are no basements in this area (the soil is expansive and a basement would be constantly cracking and having to be repaired--you have to water your regular foundation in the summer here as it is). There is a 'tornado resistant room available' It is not even very costly.

n tornado-risk areas, homes are built only to codes that consider minimum, code-approved "design winds" much less severe than those of tornadoes or hurricanes. Various building techniques have attempted to address the problem, but the federal government hasn't sanctioned any design -- until now.

The Federal Emergency Management Agency's (FEMA) "Taking Shelter from the Storm: Building a Safe Room Inside Your House" is a 28-page on-line guide to construction plans, materials, designs and cost estimates for several types of tornado "safe rooms" you can build inside your existing or new home.

While you can't actually tornado-proof your home, the safe rooms are designed to remain standing to protect you and your family from injury caused by severe winds and life-threatening flying debris even if the rest of the home is severely damaged.

When constructed according to the plans, the safe rooms provide protection against winds of up to 250 miles per hour and against 100 mile-per-hour projectiles, according to FEMA Director James Witt. Such wind speeds are rarely exceeded in the United States so the rooms protect their inhabitants against virtually any injury.

With recommendations for both new and existing homes with various types of foundations, the plans call for small (maximum 64 square feet) reinforced wood-frame, concrete or masonry rooms that cost only $3,000 to $6,000 in a new home and 20 percent more to retrofit an existing home.
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Should building codes require them? Very few folks choose to have them built into their homes, in spite of the small cost. Why is that? It is simple, because folks look at the cost/benefit ratio and decide that they would rather spend that money on a kitchen upgrade. Now in a city that has recently been hit by a tornado, the number goes up for a couple of years.
 
I used cars as an example of the fact that most folks use a cost/risk assessment in choosing purchases for their family. YOU took it to a concrete example.

Cairenn, I think you should look at what you say. You cannot even admit that you are the one who conflated the issue and have to try to pass the buck on to me. Seriously, think about what you are doing here, it is irrational.

Let's try this one instead. I live in tornado alley. There are no basements in this area (the soil is expansive and a basement would be constantly cracking and having to be repaired--you have to water your regular foundation in the summer here as it is). There is a 'tornado resistant room available' It is not even very costly.

Should building codes require them? Very few folks choose to have them built into their homes, in spite of the small cost. Why is that? It is simple, because folks look at the cost/benefit ratio and decide that they would rather spend that money on a kitchen upgrade. Now in a city that has recently been hit by a tornado, the number goes up for a couple of years.

I already stated
No, you are misunderstanding what I say. I am simply trying to establish why some buildings are able to withstand intense fires for protracted periods without collapse whilst WTC buildings conspicuously did not.

I am also suggesting that high rise and medium rise buildings, (anything over the height attainable by ladders), should be able to withstand very serious fire without collapsing as in particular, WTC7 did. I am also trying to ascertain, how many buildings are out there which are likely to collapse during an intense fire of more than 2 hrs?

Does that honestly sound like I am talking about private houses?

I do not wish to allow conflation again, so as private houses clearly have nothing to do with commercial high and medium rise blocks which this thread is about, can we please stick within those parameters?

Now are you suggesting that high and medium rise blocks should be engineered to allow WTCs 1,2 and 7 like collapses due to severe and protracted fires, on grounds of cost?

Would you agree that as previous examples of prolonged severe fires have not had the effect of collapsing such buildings, there may be some inherent flaw in the design of WTCs and who knows how many other buildings?

Does it not seem sensible to investigate this possibility?

Do you think such buildings should still be standing after protracted and intense fires, like the ones cited at the beginning of the thread did, irrespective of cost?
 
Would you agree that as previous examples of prolonged severe fires have not had the effect of collapsing such buildings, there may be some inherent flaw in the design of WTCs and who knows how many other buildings?

Does it not seem sensible to investigate this possibility?

But isn't that what the NIST investigation did? They found what the flaws were, and they issued recommendations.

http://www.nist.gov/el/disasterstudies/wtc/faqs_wtc7.cfm

Does this mean there are hundreds or thousands of unsafe tall buildings with long span supports that must be retrofitted in some way? How would you retrofit a building to prevent this problem?

While the partial or total collapse of a tall building due to fires is a rare event, NIST strongly urges building owners, operators, and designers to evaluate buildings to ensure the adequate fire performance of structural systems. Of particular concern are the effects of thermal expansion in buildings with one or more of the following characteristics: long-span floor systems, connections that cannot accommodate thermal effects, floor framing that induces asymmetric forces on girders, and composite floor systems, whose shear studs could fail due to differential thermal expansion (i.e., heat-induced expansion of material at different rates). Engineers should be able to design cost-effective fixes to address any areas of concern identified by such evaluations.
Several existing, emerging, or even anticipated capabilities could have helped prevent the collapse of WTC 7. The degree to which these capabilities improve performance remains to be evaluated. Possible options for developing cost-effective fixes include:

  • More robust connections and framing systems to better resist effects of thermal expansion on the structural system.
  • Structural systems expressly designed to prevent progressive collapse. Current model building codes do not require that buildings be designed to resist progressive collapse.
  • Better thermal insulation (i.e., reduced conductivity and/or increased thickness) to limit heating of structural steel and minimize both thermal expansion and weakening effects. Insulation has been used to protect steel strength, but it could be used to maintain a lower temperature in the steel framing to limit thermal expansion.
  • Improved compartmentation in tenant areas to limit the spread of fires.
  • Thermally resistant window assemblies to limit breakage, reduce air supply and retard fire growth.

NIST is recommending that building standards and codes be strengthened beyond their current intent to achieve life safety to prevent structural collapse even during infrequent building fires like those in WTC 7 when sprinklers do not function, do not exist, or are overwhelmed by fire.
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I would suggest that more lives are lost in private homes than in high rise fires. Why should there not be regulations for them?
 
But isn't that what the NIST investigation did? They found what the flaws were, and they issued recommendations.

http://www.nist.gov/el/disasterstudies/wtc/faqs_wtc7.cfm

Does this mean there are hundreds or thousands of unsafe tall buildings with long span supports that must be retrofitted in some way? How would you retrofit a building to prevent this problem?

While the partial or total collapse of a tall building due to fires is a rare event, NIST strongly urges building owners, operators, and designers to evaluate buildings to ensure the adequate fire performance of structural systems. Of particular concern are the effects of thermal expansion in buildings with one or more of the following characteristics: long-span floor systems, connections that cannot accommodate thermal effects, floor framing that induces asymmetric forces on girders, and composite floor systems, whose shear studs could fail due to differential thermal expansion (i.e., heat-induced expansion of material at different rates). Engineers should be able to design cost-effective fixes to address any areas of concern identified by such evaluations.
Several existing, emerging, or even anticipated capabilities could have helped prevent the collapse of WTC 7. The degree to which these capabilities improve performance remains to be evaluated. Possible options for developing cost-effective fixes include:

  • More robust connections and framing systems to better resist effects of thermal expansion on the structural system.
  • Structural systems expressly designed to prevent progressive collapse. Current model building codes do not require that buildings be designed to resist progressive collapse.
  • Better thermal insulation (i.e., reduced conductivity and/or increased thickness) to limit heating of structural steel and minimize both thermal expansion and weakening effects. Insulation has been used to protect steel strength, but it could be used to maintain a lower temperature in the steel framing to limit thermal expansion.
  • Improved compartmentation in tenant areas to limit the spread of fires.
  • Thermally resistant window assemblies to limit breakage, reduce air supply and retard fire growth.

NIST is recommending that building standards and codes be strengthened beyond their current intent to achieve life safety to prevent structural collapse even during infrequent building fires like those in WTC 7 when sprinklers do not function, do not exist, or are overwhelmed by fire.
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Quite, but we can find no evidence where that has been done, even with regard to the new 7, which was built, (The building was officially opened at noon on May 23, 2006) prior to the recommendations, (
[h=1]Investigation (09/17/2010, ARCHIVE, incorporated into 9/19/2011 update),[/h]
Also, it appears we already had the design off pat, evidenced by the prior cases which remained standing, some even with sufficient integrity to allow the mounting of cranes on them post fire, and went for a less robust design which collapses after a few hours at breakneck speed.
 
Quite, but we can find no evidence where that has been done, even with regard to the new 7, which was built, (The building was officially opened at noon on May 23, 2006) prior to the recommendations, (
Investigation (09/17/2010, ARCHIVE, incorporated into 9/19/2011 update),


Also, it appears we already had the design off pat, evidenced by the prior cases which remained standing, some even with sufficient integrity to allow the mounting of cranes on them post fire, and went for a less robust design which collapses after a few hours at breakneck speed.

It appears they still tried to make the building safer.

http://en.wikipedia.org/wiki/7_World_Trade_Center#Design


The building is being promoted as the safest skyscraper in the U.S.[64] According to Silverstein Properties, the owner of the building, it "will incorporate a host of life-safety enhancements that will become the prototype for new high-rise construction".[65] The building has 2 ft (60 cm) thick reinforced-concrete and fireproofed elevator and stairway access shafts. The original building used only drywall to line these shafts.[66] The stairways are wider than in the original building to permit faster egress.[66]
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And I highly recommend you read ALL of that FAQ, as it deals with several issues:

http://www.nist.gov/el/disasterstudies/wtc/faqs_wtc7.cfm

Yes, thanks, I have read a large amount of that... Also the https://www.metabunk.org/files/NCSTAR_1-9_WTC7_unlocked.pdf which although is 'unlocked', I cannot copy graphics from.

The following factors describe the fire events that occurred in both WTC 7 and the referenced buildings:


  • The fuel for the fires was ordinary office combustibles at ordinary combustible load levels.
  • There was no use of accelerants.
  • The spread of fire from combustible to combustible was governed by ordinary fire physics.
  • Fire-induced window breakage provided ventilation for continued fire spread and growth.
  • There were simultaneous fires on multiple floors.
  • The fires on each floor occupied a substantial portion of the floor.
  • The fires on each floor had passed the point of flashover and the structure was subjected to typical post-flashover temperatures.
  • The sprinklers were inoperative or ineffective; and 9) the fires burned for sufficient time to cause significant distortion and/or failure to the building structure.
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Seems particularly relevant to this thread.
 
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It appears they still tried to make the building safer.

http://en.wikipedia.org/wiki/7_World_Trade_Center#Design


The building is being promoted as the safest skyscraper in the U.S.[64] According to Silverstein Properties, the owner of the building, it "will incorporate a host of life-safety enhancements that will become the prototype for new high-rise construction".[65] The building has 2 ft (60 cm) thick reinforced-concrete and fireproofed elevator and stairway access shafts. The original building used only drywall to line these shafts.[66] The stairways are wider than in the original building to permit faster egress.[66]
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Undoubtedly, and prior to the collapses such assurances should have allayed any fears, but in the light of the catastrophic collapses, especially as it is blamed on one single support failure; such changes appear very minor. And given the higher redundancy of the other examples, I would have expected far deeper ramifications to the event, (with regard to design and safety) and especially much stronger assurances re ability to survive protracted fire without collapse.

I would also have expected much greater interest and publicity, (in order to reassure), of retrofits on other similar buildings.

It does appear the NIST recommendations have largely been disregarded.
 
Undoubtedly, and prior to the collapses such assurances should have allayed any fears, but in the light of the catastrophic collapses, especially as it is blamed on one single support failure; such changes appear very minor. And given the higher redundancy of the other examples, I would have expected far deeper ramifications to the event, (with regard to design and safety) and especially much stronger assurances re ability to survive protracted fire without collapse.

I would also have expected much greater interest and publicity, (in order to reassure), of retrofits on other similar buildings.

It does appear the NIST recommendations have largely been disregarded.

All of what you said sounds like conjecture. Can you provide any proof? Is it the same design?
 
All of what you said sounds like conjecture. Can you provide any proof? Is it the same design?

All I can say is, I can't find anywhere that discusses any major structural design changes, so yes I am assuming it is principally the same. I cant even find anywhere that offers an assurance that, 'in the event of a fire', the same support wouldn't fail again. Now you may well say 'that would obviously be taken into account and remedied', but is there any evidence for that. I think it strange.
 
All I can say is, I can't find anywhere that discusses any major structural design changes, so yes I am assuming it is principally the same. I cant even find anywhere that offers an assurance that, 'in the event of a fire', the same support wouldn't fail again. Now you may well say 'that would obviously be taken into account and remedied', but is there any evidence for that. I think it strange.

One change is they built a fireproof concrete core. There wasn't one in the original. The stairway was lined with drywall.

http://web.archive.org/web/20060517...t_updates/7_world_trade_center_75464.asp#faqs

Q: How is the new 7 WTC different from the original building?
A: The original 7 WTC stood 47 stories tall, between West Broadway and Washington Street. The new building is 52 stories (750 feet) tall and is narrower, to allow for the reopening of Greenwich Street through the main Trade Center site -- under which the 1 and 9 subway lines run. While both the original and the new tower accommodate the Con Edison substation in their lower 11 floors, the new building has many new safety and environmental features. For instance, the new building is built with two-foot-thick, fireproofed concrete walls in its core structure, which houses stairwells, utilities, and emergency features like back-up phones and lighting. It also is built partly with recycled materials and is engineered to conserve water and energy.
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One change is they built a fireproof concrete core. There wasn't one in the original. The stairway was lined with drywall.

http://web.archive.org/web/20060517...t_updates/7_world_trade_center_75464.asp#faqs

Q: How is the new 7 WTC different from the original building?
A: The original 7 WTC stood 47 stories tall, between West Broadway and Washington Street. The new building is 52 stories (750 feet) tall and is narrower, to allow for the reopening of Greenwich Street through the main Trade Center site -- under which the 1 and 9 subway lines run. While both the original and the new tower accommodate the Con Edison substation in their lower 11 floors, the new building has many new safety and environmental features. For instance, the new building is built with two-foot-thick, fireproofed concrete walls in its core structure, which houses stairwells, utilities, and emergency features like back-up phones and lighting. It also is built partly with recycled materials and is engineered to conserve water and energy.
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Well that at least is a substantial difference, hopefully it will never need to be put to the test. It is very difficult to find information on the new building tho. I would have thought they would have made more of a point in emphasising safety re collapse liability.

Do you have any idea how to find out if any retrofits have been done to other buildings in line with the recommendations?
 
More changes:

http://www.emporis.com/building/seven-world-trade-center-new-york-city-ny-usa

The fireproofing material that coats the steel structure is 5 times thicker than is required by code.
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These don't seem very robust attributes though.

Typical office floors have 10-foot floor-to-ceiling windows, nine-foot clear ceiling heights and 45’ lease spans that are virtually column free.
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Seems a long span given the previous collapse.

Now this is downright weird IMO

Unlike other buildings in the new WTC complex that had to go through a several year long process of quarrels and lawsuits, this building was approved without extra hassle within a few months of September 11, 2001.
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WTC 7 collapses in seconds due to fire and within a few months new plans are approved to replace it when they do not even know why it failed.

Come on, there is no way anyone can accuse me of being paranoid for finding that weird surely

And this is what they say about potential terrorist attack:

To counter large shards of flying glass resulting from a terrorist attack, glazing is laminated tempered safety glass
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Not, 'we have ensured it will not pancake down like the last one', or 'an innovative and powerful sprinkler system has been installed with water feeds from different sources'.

It seems ill thought out and hasty to me, almost as if they are saying, there was nothing wrong with the last one but we made this one even better.
 
The fire burned for hours first, and the building also had damage from the WTC falling.

Question, was anyone killed when it fell? Did it survive long enough for folks to evacuate it?
 
The fire burned for hours first, and the building also had damage from the WTC falling.

Question, was anyone killed when it fell? Did it survive long enough for folks to evacuate it?

That really isn't the question. The question is, why did it fall after minor fires and a few hours when other comparable buildings did not collapse after very many hours of extreme fire?

Now the answer must be in design flaws, column 79 failure facilitating the whole collapse. And yet no one talks about how this flaw has been addressed.
 
That really isn't the question. The question is, why did it fall after minor fires and a few hours when other comparable buildings did not collapse after very many hours of extreme fire?

Now the answer must be in design flaws, column 79 failure facilitating the whole collapse. And yet no one talks about how this flaw has been addressed.

It was addressed by the recommendations listed above.

What do you want? An act of congress?
 
And they were not "minor" fires. Less extreme perhaps, but they were still major multi-story fires burning for hours. See 5.6 in NIST NCSTAR 1-9
 
It was addressed by the recommendations listed above.

What do you want? An act of congress?

Recommendations are not worth the paper they are printed on if they are not acted on. It appears they have been largely ignored.

I would like to see evidence that they have been acted on both in regard to retrofitting and also new builds.

Does this mean there are hundreds or thousands of unsafe tall buildings with long span supports that must be retrofitted in some way?NIST strongly urges building owners, operators, and designers to evaluate buildings to ensure the adequate fire performance of structural systems. Of particular concern are the effects of thermal expansion in buildings with one or more of the following characteristics: long-span floor systems, connections that cannot accommodate thermal effects, floor framing that induces asymmetric forces on girders, and composite floor systems, whose shear studs could fail due to differential thermal expansion (i.e., heat-induced expansion of material at different rates).
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Are you seriously telling me that you do not find it strange that within a few months of 7 collapsing, they had approved a replacement?

They have as yet not established the failure mechanism for the most spectacular collapses in history and yet they are straightaway building a replacement without understanding what went wrong:confused:

And the fires were minor in the scheme of things and should not have brought the building down.

STILL STANDING AFTER 18 HOURS



TOTAL COLLAPSE AFTER 3 HOURS
 
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They did find a cause. The weakened steel.

I still want to know if any one died in WTC 7. What is important is for the building to last long enough that the folks in it are able to escape.

Even in WTC 1 and 2
In each tower, 99% of the occupants below the crash survived. At the impact area and above, survival was limited to just a handful of people in the south tower who made an amazing escape.
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In fact that is best evidence that the building fell because of the planes, and not with controlled demolitions. The death toll would have been so much higher if they had fallen earlier.
 
Here is a recent 'raging inferno'. No collapse, (unless some bits falling off are to be categorised as a partial total collapse... seems only fair... bits fell off and they did hit the floor).



http://www.guardian.co.uk/world/video/2013/apr/04/chechnya-skyscraper-on-fire-video

A fire engulfs a 40-storey skyscraper in Grozny, Chechnya. The Olympus tower is the tallest building in the north Caucasus region of southern Russia. The fire extends up one whole corner of the building with multiple floors ablaze. More than 80 firefighters were required to tackle the towering inferno. The 140-metre-high building was opened in 2011 and includes luxury apartments and a five-star hotel
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Sure did get rid of WTC 7 fast. Here is a pic taken 23rd Sept 2001.

http://911research.wtc7.net/wtc/evidence/photos/gzaerial3.html
[h=2]High-Resolution Aerial Photo of the Devastation of Lower Manhattan[/h] This photograph is a cropped and reduced version of an even higher-resolution photograph taken from an airplane flying at an altitude of 3,300 feet on September 23, 2001. The central portion of the image is magnified here. The complete, full-resolution image is available at NOAA's website here, and a cropped version of the image is here, 1
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They did find a cause. The weakened steel.

The cause is allegedly failure of one column (79 on the east-side) due to 'thermal expansion', which led to a near perfectly symmetrical collapse.

I still want to know if any one died in WTC 7. What is important is for the building to last long enough that the folks in it are able to escape.
There were reports of people stepping over dead bodies but that is really off topic.

To avoid conflating the issue, perhaps you would like to start a separate thread on 'Fire Safety in High/Medium Rise Buildings'?
 
And what is it supposed to be showing us? The WTC7 debris seems to be still there. Is there a shortly after pic?

There is a hell of a lot already cleared away in a very short time. You can see the trucks carrying it away in the pic if you look carefully. Better to click the links as it does not show well in the post.
 
There is a hell of a lot already cleared away in a very short time. You can see the trucks carrying it away in the pic if you look carefully. Better to click the links as it does not show well in the post.

Here's a sharpened crop of the WTC7 site:


Yes, they cleared away the steel quickly. And yes, it would be better from an investigation perspective if they did it more carefully, labling each piece with where it was found, taking photos in-situ, etc.

But there were a bunch of conflicting priorities. Initially it was search and rescue. Then it was making the site safe to work in. Then recovery of human remains. Then opening the area to traffic.

Since the cause of the disaster seemed quite apparent (the two planes, the fires), then structural investigation was not given the priority it might have, had it been some unexpected collapse with no buried people.
 
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Here's a sharpened crop of the WTC7 site:


.

I have to say, there appears remarkably little damage to the surrounding buildings, considering it 'wasn't' a planned demolition.
 
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Like this one:


Yes, considering 7 came down 'randomly', it could have caused much more damage than it did, i.e. if it had not come down symmetrically but had fallen sideways/backwards or forwards, (sorry, not forwards), or a chaotic combination. Well I think it remarkable but that's just me and ...?
 
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What is this constantly reference to buildings 'falling over'? They are not trees or smoke stacks. They have a BROAD base and it would be MUCH harder for a building to 'fall over' than it would be to pancake mostly.

Can anyone find a skyscraper that has 'fallen over'? even when hit with high winds? a tornado? a tsunami? by any type of a disaster?

I can pictures of buildings under 20 stories falling over. It seems that they all seem to be apartment buildings. Is that important? It could be, because apartments are not spaces effected by columns. Folks aren't interested in LARGE columnless spaces.

A skyscraper hit by a tornado

http://en.wikipedia.org/wiki/1970_Lubbock_tornado


Lots of great explanations of the WTC buildings and their collapse

http://www.debunking911.com/collapse.htm

http://www.debunking911.com/thermite.htm
 
What is this constantly reference to buildings 'falling over'? They are not trees or smoke stacks. They have a BROAD base and it would be MUCH harder for a building to 'fall over' than it would be to pancake mostly.

Can anyone find a skyscraper that has 'fallen over'? even when hit with high winds? a tornado? a tsunami? by any type of a disaster?

Take your pick really... Google buildings topple... images:

https://www.google.co.uk/search?q=b...Ud_GFoHcOc7FgdAJ&ved=0CD0QsAQ&biw=979&bih=457
 
It's nothing more than a Gish Gallop of pictures, heck the leaning tower of Pisa is even included.
 
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