Reply
 
Thread Tools Display Modes
  #1  
Old 04-20-2015, 12:26 AM
Contemplation Contemplation is offline
Guest
 
Join Date: Sep 2014
Posts: 160
Why do skyscrapers fall straight down and not fall over?

Unlike a tree, a sky scraper just crumbles drectly on top of this. Even the world trade center fell straight down.

Why does it not lean into other buildings and fall sideways like a tree?
  #2  
Old 04-20-2015, 12:32 AM
garygnu garygnu is offline
Guest
 
Join Date: Feb 2006
Location: Port Orchard, WA
Posts: 11,087
Buildings are mostly hollow. Trees can not collapse upon themselves.
  #3  
Old 04-20-2015, 12:37 AM
Sage Rat Sage Rat is offline
Member
 
Join Date: Mar 2004
Location: Howdy
Posts: 18,962
Quote:
Originally Posted by garygnu View Post
Buildings are mostly hollow. Trees can not collapse upon themselves.
Plus, a tree has long fibers running down its length that act as a single piece. A building is formed of millions of discrete pieces that are fairly weakly bonded to one another.

Like, if you have a house of cards, knocking out a wall near the bottom simply removes the support from all the upper layers. The wall isn't a single part that continues up to the roof. Its scope is limited to the one floor it is on. Tipping it over doesn't tip over anything else in the structure. But now that the support has been removed, everything is going to cave in.
  #4  
Old 04-20-2015, 12:57 AM
beowulff beowulff is offline
Member
 
Join Date: May 2001
Location: Scottsdale, more-or-less
Posts: 15,089
But, the WTC towers collapsed from the top.
If they were compromised at the bottom, the fall might not have been as vertical.
  #5  
Old 04-20-2015, 01:07 AM
Northern Piper Northern Piper is offline
Charter Member
 
Join Date: Jun 1999
Location: Je suis Ikea.
Posts: 25,649
When you cut down a tree, you cut it from one direction at the base. That weakens the support for the tree on one side, and when the support is sufficiently weakened, it will fall to the side of the cut.

When a tree falls due to high wind, it's the same thing: the force pushing the tree to fall is coming from one direction, so the tree falls in the direction pushed by the wind.

As beowulff says, if you were to start to destroy a building from one side, then it would fall towards the loss of support. But that would be very dangerous, to have a building fall over, especially a tall building in a built-up area. So when a building is destroyed intentionally, by implosion, the explosives are planted in a way that the building loses support simultaneously on all sides of the building. With uniform loss of support, the building will pancake down.

Similarly, for the WTC, the support was lost at the upper levels essentially uniformly, and therefore the upper floors started falling straight down. The overload of weight from the initial collapsed floors was distributed uniformly, so the next floor down collapsed uniformly, and so on all the way down.

Last edited by Northern Piper; 04-20-2015 at 01:09 AM.
  #6  
Old 04-20-2015, 01:07 AM
Nava Nava is offline
Guest
 
Join Date: Nov 2004
Location: Hey! I'm located! WOOOOW!
Posts: 37,472
They're designed to fall like that; a lot of structural studies are done specifically to design them that way. Even so, when there is a scheduled demolition a lot more structural studies are done specifically to ensure the building falls in rather than out.

Now if you want the mathematical details, that's beyond me.
  #7  
Old 04-20-2015, 01:15 AM
Northern Piper Northern Piper is offline
Charter Member
 
Join Date: Jun 1999
Location: Je suis Ikea.
Posts: 25,649
Just realised that in the example I gave of cutting a tree down, I was thinking of an axe cut, which removes the support from one side.

Saw cuts don't remove the support from one side, and do allow for a tree to be pulled over towards the other side from the cut, by ropes, but again, the cut being asymetrical leads to the tree falling in one direction.
  #8  
Old 04-20-2015, 02:14 AM
boytyperanma boytyperanma is offline
Guest
 
Join Date: Dec 2005
Location: Leominster MA
Posts: 5,222
I think the question has been answered pretty well. I just wanted to add skyscrapers have a much higher width to hieght ratio than a tree. The WTC buildings hieght to width ratio was about 6to1. An eastern white pines ratio is 20to1.

Even if trees were hollow like buildings they would have less area within themselves to fall into.
  #9  
Old 04-20-2015, 02:36 AM
marshmallow marshmallow is offline
Guest
 
Join Date: Oct 2004
Posts: 6,764
Skyscrapers don't have the strength to support their weight while leaning horizontally, they would just fall apart. They're built to withstand horizontal forces like wind, earthquakes, or the momentary shock of an airplane crash.

I can imagine a building sliding to one side, but it wouldn't topple like a tree. More like pushing over a giant pile of stuff. Has anything like that ever happened?

AFAIK it's like when Superman or other super strength heroes hold up an airplane or ocean cruiser. Cute, but you'd just end up with a giant hole where Superman is because the superstructure can't support its weight like that.
  #10  
Old 04-20-2015, 03:16 AM
Francis Vaughan Francis Vaughan is offline
Member
 
Join Date: Sep 2009
Location: Adelaide, Australia
Posts: 4,751
A toppling tree is subject to a lot of forces you don't really appreciate, and it is only the inherent strength of the tree that stops you seeing these, plus the way a tree is felled also hides some of this.

Perhaps one the the best things to observe is an industrial chimney being felled. These are not always dropped inside their own base, and if there is room they will be felled by toppling them. But they won't fall over a a lump like a tree, they will fracture as they fall. The reason is that any falling object likes to fall as accelerated by gravity - this means it accelerates at 9.8ms-2. But a long object falling in an arc can't accelerate like this, the top is being pulled down faster than this by the lower parts, and eventually the stresses build up to the point where the chimney fractures.

This chimney in Poland was reinforced concrete, so had a lot of tensile strength and didn't fracture until quite a way down.

This one in Sydney neatly fractures at its mid point.

You will see simple brick chimneys fracture in multiple places.

The other think with trees that you don't often appreciate is that they want to rotate around their centre of rotational inertia, which is not at ground level. A tree falling is held in place at the ground by the remaining wood attaching it to the root system, and so rotates around the base. A tree falling where this attachment fails will kick back as its centre of rotation changes. This is why you never stand behind a tree being felled.

Last edited by Francis Vaughan; 04-20-2015 at 03:17 AM.
  #11  
Old 04-20-2015, 03:53 AM
ouryL ouryL is offline
Charter Member
 
Join Date: Mar 2003
Location: 21 20' N 157 55' W
Posts: 6,519
A concrete shell cannot support itself without eternal steel skeleton.
In Japan, an earthquake proof building DID just fall other.
  #12  
Old 04-20-2015, 07:58 AM
Machine Elf Machine Elf is offline
Guest
 
Join Date: Feb 2007
Location: Challenger Deep
Posts: 10,553
Quote:
Originally Posted by marshmallow View Post
Skyscrapers don't have the strength to support their weight while leaning horizontally, they would just fall apart.
Not always true. Masonry (brickwork) typically lacks tensile strength, but a modern skyscraper with welded steel columns can have pretty good structural integrity.

Also, this building fell over and mostly maintained its integrity, not really collapsing until it started laying down on the ground.

Same with this one.

These were all relatively short, fat buildings though. Apart from the WTC towers, I don't think we've seen a truly monstrous skyscraper suffer an inadvertent collapse, so it's hard to say for certain what they would do if you compromised the foundation on one side.

Quote:
Originally Posted by ouryL
A concrete shell cannot support itself without eternal steel skeleton.
In Japan, an earthquake proof building DID just fall other.
Got a cite for that? Older homes in Japan sometimes collapse during earthquakes, but I'm not aware of any skyscrapers that have done so. In fact, it seems to me that they performed pretty well in one of the biggest quakes ever.
  #13  
Old 04-20-2015, 09:52 AM
TriPolar TriPolar is offline
Guest
 
Join Date: Oct 2007
Location: rhode island
Posts: 37,980
Didn't you guys play with blocks when you were kids? Building a huge tower and toppling it would result in most of the blocks falling near the base of the tower as gravity took over once it began to topple. Most structures seem to be a solid structure but they are mainly held together by their weight bearing down vertically. If you constructed a building horizontally on the ground and tried to raise it to a vertical position from one end it would break in the center.
  #14  
Old 04-20-2015, 10:18 AM
Omar Little Omar Little is offline
Guest
 
Join Date: Apr 2000
Location: Within
Posts: 11,675
Expert demolitionist can pretty much make a building fall in any direction they want.
  #15  
Old 04-20-2015, 10:44 AM
johnpost johnpost is offline
Guest
 
Join Date: Jul 2009
Posts: 12,056
you can see video of chimney demolition gone wrong and they come down like a tree (sort of until part way).
  #16  
Old 04-20-2015, 10:46 AM
davida03801 davida03801 is offline
BANNED
 
Join Date: Aug 2013
Posts: 1,481
Axe or chainsaw you basically use the same concept. You cut the "directional notch" first to point the tree to fall in the direction you want. Then cut the other side a bit above the notch and generally the tree falls down in the direction you want.

I spent two summers doing just that with both axe and chainsaw cutting trails long long ago in my younger days.

Quote:
Originally Posted by Northern Piper View Post
Just realised that in the example I gave of cutting a tree down, I was thinking of an axe cut, which removes the support from one side.

Saw cuts don't remove the support from one side, and do allow for a tree to be pulled over towards the other side from the cut, by ropes, but again, the cut being asymetrical leads to the tree falling in one direction.
  #17  
Old 04-20-2015, 11:02 AM
TriPolar TriPolar is offline
Guest
 
Join Date: Oct 2007
Location: rhode island
Posts: 37,980
Quote:
Originally Posted by davida03801 View Post
Axe or chainsaw you basically use the same concept. You cut the "directional notch" first to point the tree to fall in the direction you want. Then cut the other side a bit above the notch and generally the tree falls down in the direction you want.

I spent two summers doing just that with both axe and chainsaw cutting trails long long ago in my younger days.
Trees fall in the direction of their center of balance unless you apply some other force to them. Straight tall trees can be made to fall in the direction of a notch, if you don't trim the branch from spreading trees they'll fall in the direction of the heaviest part of the tree.
  #18  
Old 04-20-2015, 11:06 AM
leahcim leahcim is offline
Member
 
Join Date: Dec 2010
Location: Boulder, CO
Posts: 3,485
When it comes down to it, gravity pulls down (by the definition of "down"). If some part of a building/tree fell to the side there must have been some significant force other than gravity working on it. For trees, the internal stress forces are comparable in size to gravity so they can "push" the higher parts of the tree to the side as they fall. Buildings are made much more sparsely of heavier materials so the ratio of internal stress forces to gravity is smaller on average.
  #19  
Old 04-20-2015, 12:29 PM
Northern Piper Northern Piper is offline
Charter Member
 
Join Date: Jun 1999
Location: Je suis Ikea.
Posts: 25,649
Quote:
Originally Posted by davida03801 View Post
Axe or chainsaw you basically use the same concept. You cut the "directional notch" first to point the tree to fall in the direction you want. Then cut the other side a bit above the notch and generally the tree falls down in the direction you want.
I was thinking of a hand-held lumberjack saw, which makes a straight cut without a notch, but agree a chain-saw notch cut works the same as an axe.
  #20  
Old 04-20-2015, 05:44 PM
Hari Seldon Hari Seldon is offline
Member
 
Join Date: Mar 2002
Location: Trantor
Posts: 11,405
Think of how much horizontal momentum you would have to impart to the upper storeys to get it to topple sideways. Tall buildings just are not strong under tension (why would you bother to make it so?) to resist breaking while trying to impart that momentum. Trees bend rather than break, but tall buildings cannot.

In the 1993 attempt they tried to take down one vertical pillar. I read that had they suceeded (the truck bomb was just a bit too far away from it) the building would have fallen. As it happened I was just a few blocks away (walking south of Broadway at about Chambers street) and I tried to imagine what lower Manhattan would have looked like with the tower lying across it. But eventually I realized that it would have broken into several pieces and mostly fallen straight down.
  #21  
Old 04-20-2015, 05:53 PM
Hail Ants Hail Ants is offline
BANNED
 
Join Date: Jan 2000
Location: NY USA
Posts: 7,635
Quote:
Originally Posted by beowulff View Post
But, the WTC towers collapsed from the top.
If they were compromised at the bottom, the fall might not have been as vertical.
No. There is no force in the universe that could ever cause a skyscraper to 'topple over' sideways. Regardless of how it looks tall buildings are not solid objects, they are a pile of framework steel constantly in balance against the force of gravity pulling down trying to collapse it under its own weight. Even if you could somehow magically 'push' against an entire side of one the instant its center of gravity moved slightly off-center it will collapse straight down. Every time. No exceptions.

In fact, if you watch the video of the second WTC tower collapsing, because it was struck much lower the upper half actually did start to tip a little when the middle gave way. But, as stated above, it immediately collapsed straight down.

Last edited by Hail Ants; 04-20-2015 at 05:56 PM.
  #22  
Old 04-20-2015, 07:06 PM
Snnipe 70E Snnipe 70E is offline
Guest
 
Join Date: Oct 2008
Location: San Jose, CA
Posts: 3,787
If you take the supports out of one side of a high rise it will begin to lean a little and then collapse. That is when gravity begins to take over Most of the parts will fall straight down but the pile will be higher on the side where the supports were removed. But the building is not going to arc down.
  #23  
Old 04-20-2015, 07:31 PM
beowulff beowulff is offline
Member
 
Join Date: May 2001
Location: Scottsdale, more-or-less
Posts: 15,089
Quote:
Originally Posted by Hail Ants View Post
No. There is no force in the universe that could ever cause a skyscraper to 'topple over' sideways. Regardless of how it looks tall buildings are not solid objects, they are a pile of framework steel constantly in balance against the force of gravity pulling down trying to collapse it under its own weight. Even if you could somehow magically 'push' against an entire side of one the instant its center of gravity moved slightly off-center it will collapse straight down. Every time. No exceptions.

In fact, if you watch the video of the second WTC tower collapsing, because it was struck much lower the upper half actually did start to tip a little when the middle gave way. But, as stated above, it immediately collapsed straight down.
Incorrect.

Buildings might not fall over like a tree, but they can definitely fall far to one side, and not just "straight down."

Just look at the video of the chimney posted farther up - it clearly toppled over, and not straight down.

ETA: Here's an example: https://www.youtube.com/watch?v=dt9GaIEdh3I

Last edited by beowulff; 04-20-2015 at 07:34 PM.
  #24  
Old 04-20-2015, 07:44 PM
Musicat Musicat is offline
Charter Member
 
Join Date: Oct 1999
Location: Sturgeon Bay, WI USA
Posts: 19,977
Quote:
Originally Posted by Contemplation View Post
Unlike a tree, a sky scraper just crumbles drectly on top of this. Even the world trade center fell straight down.

Why does it not lean into other buildings and fall sideways like a tree?
Why would it lean at all if all support below is removed simultaneously? It's only when support is removed unequally that it will tilt. There is no inherent tendency to tilt over in all structures.

Most buildings are tall and thick. Most trees are tall and thin. Think there might be an important difference here with respect to gravity and the center of it?
  #25  
Old 04-20-2015, 07:51 PM
RealityChuck RealityChuck is offline
Charter Member
 
Join Date: Apr 1999
Location: Schenectady, NY, USA
Posts: 40,912
The World Trade Center was a new design where the supporting walls were on the outside. Usually, there's a central core that holds up the building, but that takes up space, so the architect did it so the outside wall supported everything. Once the wall was breached, the floor above the breach would fall down, creating the chain reaction we saw.

Older building would stand up better, but would be more likely to topple sideways, since the central core would prevent the floors from falling straight down.
__________________
"If a person saying he was something was all there was to it, this country'd be full of rich men and good-looking women. Too bad it isn't that easy.... In short, when someone else says you're a writer, that's when you're a writer... not before."
Purveyor of fine science fiction since 1982.
  #26  
Old 04-20-2015, 10:08 PM
Hail Ants Hail Ants is offline
BANNED
 
Join Date: Jan 2000
Location: NY USA
Posts: 7,635
Quote:
Originally Posted by beowulff View Post
Incorrect.

Buildings might not fall over like a tree, but they can definitely fall far to one side, and not just "straight down."

Just look at the video of the chimney posted farther up - it clearly toppled over, and not straight down.

ETA: Here's an example: https://www.youtube.com/watch?v=dt9GaIEdh3I
That's masonry, not a true skyscraper.

Quote:
Originally Posted by RealityChuck View Post
The World Trade Center was a new design where the supporting walls were on the outside. Usually, there's a central core that holds up the building, but that takes up space, so the architect did it so the outside wall supported everything. Once the wall was breached, the floor above the breach would fall down, creating the chain reaction we saw.

Older building would stand up better, but would be more likely to topple sideways, since the central core would prevent the floors from falling straight down.
Before buildings were made with structural steel frameworks they relied on masonry walls for support. Consequently buildings couldn't be much taller than ten stories. As such, no skeletal steel supported building much taller than ten stories could ever topple over like a tree. They always collapse straight down under their own weight.

Last edited by Hail Ants; 04-20-2015 at 10:08 PM.
  #27  
Old 04-20-2015, 10:26 PM
msmith537 msmith537 is offline
Guest
 
Join Date: Jan 2001
Posts: 26,467
Quote:
Originally Posted by Hari Seldon View Post
... Tall buildings just are not strong under tension (why would you bother to make it so?) to resist breaking while trying to impart that momentum. Trees bend rather than break, but tall buildings cannot.
Because a tall building is subject to a strong wind load and experiences a fair amount of tension on the side facing the direction where the wind is coming from. And tall buildings do "bend" because of this.

It's also the reason that concrete columns contain steel reinforcing bars. It's not for compression (the concrete is more than adequate for that).


Also, a tall building can, in fact, topple over like a domino. Particularly if they are made from steel frames (which are strong in tension).

The reason the World Trade Center towers came crashing straight down is because they were designed as a bunch of concrete slabs suspended by pins within a tall metal tube. The collapse started towards the top where the planes hit and each slab pancaked straight down on the floor below it.
  #28  
Old 04-20-2015, 10:26 PM
beowulff beowulff is offline
Member
 
Join Date: May 2001
Location: Scottsdale, more-or-less
Posts: 15,089
Quote:
Originally Posted by Hail Ants View Post
That's masonry, not a true skyscraper.

Before buildings were made with structural steel frameworks they relied on masonry walls for support. Consequently buildings couldn't be much taller than ten stories. As such, no skeletal steel supported building much taller than ten stories could ever topple over like a tree. They always collapse straight down under their own weight.
Cite?
  #29  
Old 04-21-2015, 12:49 AM
Hail Ants Hail Ants is offline
BANNED
 
Join Date: Jan 2000
Location: NY USA
Posts: 7,635
It's just physics. Look at that video above. Again, its barely more than ten stories high (and very narrow). The simple fact is there is no building material that can maintain rigidity beyond its designed size & shape without collapsing under its own weight. Tall buildings may look like static 'blocks' but they're not. They are in constant compression, tension etc. against gravity. If you upset that fairly delicate balance beyond a certain point the whole structure just gives way like a house of cards. There was nothing particularly special about the Twin Towers (excluding the girders losing their fireproofing and then bending) that made it collapse straight down. If the Empire State or Chrysler Buildings were subjected to say a large enough earthquake they too would collapse in essentially the same way.
  #30  
Old 04-21-2015, 12:56 AM
beowulff beowulff is offline
Member
 
Join Date: May 2001
Location: Scottsdale, more-or-less
Posts: 15,089
You're missing the point.
Nobody here has said that a skyscraper will remain completely intact and fall over so that the top will land exactly it's height away from the base.
But, buildings are still structures, and the steel framework is welded or riveted together, to give them some amount of rigidity. If the base of a tall building was blown out on one side, the building would not fall straight down - it would lean over, and collapse at some point, but the rubble pile would extend for a significant percentage of the height of the building.

That is one reason that skyscrapers are disassembled and not imploded.
  #31  
Old 04-21-2015, 01:55 AM
Francis Vaughan Francis Vaughan is offline
Member
 
Join Date: Sep 2009
Location: Adelaide, Australia
Posts: 4,751
We probably need to define "skyscraper" and then for individual examples look carefully at the manner in which they are constructed.

The Empire State building, like all those built at that time is a steel girder structure. It is steel riveted together. These buildings defined the idea of a skyscraper. They are different to a simply tall building. Such a building will have a significant tensile strength, and if toppled would be expected to hold together much better than a building built out of ordinary reinforced concrete. It will still buckle and fracture, but it won't crumble into a shower of rubble falling straight down. A building built out of prestressed reinforced concrete is another matter. It has a greater tensile strength, but as soon as the concrete starts to fracture the internal tension will probably result in a catastrophic collapse of the structure.

The various videos of chimneys being felled demonstrates the question. Brick chimneys fall a little and then dissolve into a rain of bricks, whilst the various concrete ones have varying amounts of topple before they fracture.

But in order to topple a building, you need to give it some impetus to fall, like removing a section on one side. Dropping chimneys will involve charges placed at one side of the base, and even some preparatory removal of structure (rather like felling a tree.) Symmetric destruction of the base of a building will get movement straight down, and a nice downward collapse. You see some such demolitions go wrong and the building partially topple if there isn't symmetric destruction.
  #32  
Old 04-21-2015, 02:14 AM
Apex Rogers Apex Rogers is offline
Guest
 
Join Date: Feb 2003
Location: San Francisco, CA
Posts: 519
A sufficiently rigid structure can topple like a tree: https://youtu.be/FUK2X6XSqyo
  #33  
Old 04-21-2015, 06:50 AM
LSLGuy LSLGuy is offline
Charter Member
 
Join Date: Sep 2003
Location: Southeast Florida USA
Posts: 21,037
Good find there Apex Rogers.

Here is a pretty good vid of demolitions gone wrong. https://www.youtube.com/watch?v=oBPpfg_aWcE WARNNG: loud music.

Anyhow, in there you'll see several examples of structures that fall straight down but don't self-disassemble as expected. And several of structures that tip over and don't self-disassemble as expected.

Bottom line: a tall structure is neither a simple stack of loose blocks, nor is it a perfectly rigid object with infinite strength and a firm anchor point about which to pivot. As Francis Vaughn said so eloquently, a masonry chimney is close to the former and produces a "rain of bricks". Whereas Alex Roger's tall steel pipe is close to the other extreme, something very strong in tension and torsion with a solidly anchored pivot.

So any intact structure falling down is a mix of gravity pulling each small chunk straight down with one amount of force, and each chunk being pulled in whatever direction(s) with whatever strength(es) by all the chunks it's connected to. While the connections are stronger than the forces it remains a single unitary object. As the forces grow to exceed the connections' strengths, those connections fail and the structure fragments. The more it breaks up, the more each ever-smaller chunk's behavior becomes dominated by gravity alone.

Last edited by LSLGuy; 04-21-2015 at 06:54 AM. Reason: speling is hrad
  #34  
Old 04-21-2015, 06:59 AM
I Love Me, Vol. I I Love Me, Vol. I is offline
Charter Member
 
Join Date: May 2003
Location: Bay Area, CA
Posts: 3,948
I'm disappointed! Can't we all endeavor just a little more to trainwreck this thread into yet another WTC conspiracy screed? We've got most of the ingredients... we just need the critical mass of a nut or two to really get us going.
  #35  
Old 04-21-2015, 07:54 AM
dba Fred dba Fred is offline
Guest
 
Join Date: May 2008
Location: Arizona
Posts: 970
But will the thread then collapse or fall over?
  #36  
Old 04-21-2015, 11:24 AM
LSLGuy LSLGuy is offline
Charter Member
 
Join Date: Sep 2003
Location: Southeast Florida USA
Posts: 21,037
It'll burn from all the hidden incendiaries in each post above and below the post which starts the fire.
  #37  
Old 04-21-2015, 12:23 PM
Valgard Valgard is offline
Registered User
 
Join Date: Jan 2001
Location: SF Bay Area
Posts: 4,542
Quote:
Originally Posted by Nava View Post
They're designed to fall like that; a lot of structural studies are done specifically to design them that way. Even so, when there is a scheduled demolition a lot more structural studies are done specifically to ensure the building falls in rather than out.

Now if you want the mathematical details, that's beyond me.
I have my BS & MS in structural engineering. "How buildings fall" was never a criteria in design work and I don't even recall seeing it mentioned in any of the various codes.

We did spend a considerable amount of time designing buildings to NOT fall down and by necessity this included studying collapse mechanisms but that's not the same.

I'm sure that the companies which do controlled demolitions study this intensely but AFAIK it's not part of normal structural design.

To the OP, people have pretty much covered the basics but tall buildings don't generally topple like trees because they are not trees. They're both tall but that's about it. A tree is far stronger for it's size in certain ways compared to a building; tilt a tree 45 degrees and it'll probably be fine. Tilt a skyscraper at 45 degrees and it'll likely fall apart because it's not designed to withstand that type of loading.

If you want an example of something that can withstand a huge compressive load collapsing "straight down", stand on an empty soda can. Do it carefully and it'll hold your weight just fine, despite the supporting structure consisting of nothing more than an extremely thin sheet of aluminum. Then have someone tap the side of a can with a yardstick - a tiny bit of local buckling in the wall of the can and crunch, your weight smashes straight down and the can becomes a circle.

ETA - and then the CIA operatives will change the live video feed of the event and freefall plus explosive thermite.

Last edited by Valgard; 04-21-2015 at 12:25 PM. Reason: Cat threads must have pics, building collapse threads must have WTC CT stuff?
  #38  
Old 04-21-2015, 12:29 PM
Just Asking Questions Just Asking Questions is offline
Guest
 
Join Date: Jan 2014
Posts: 5,216
This is a great example. Thirteen stories:

Looks like a model. Like someone knocked over a structure in a model railroad. Looks fairly intact to me.

Last edited by Just Asking Questions; 04-21-2015 at 12:30 PM.
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 06:25 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@straightdope.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Publishers - interested in subscribing to the Straight Dope?
Write to: sdsubscriptions@chicagoreader.com.

Copyright 2018 STM Reader, LLC.

 
Copyright © 2017