For anyone who still doesnt think 160,000 lbs of jet fuel can make a bldg collapse

[7962]

Along with a 600 MPH impact,
I give you I-85
http://www.wsbtv.com/news/local/atlanta/large-fire-shuts-down-interstate/507589453
http://www.wsbradio.com/news/local/bridge-collapse-gdot-says-will-take-several-months-rebuild/RXsShrLkN8Zn41MabJEfiP/

And I have no doubt DU has enough engineers who could scale this to show close equality with the WTC collapse

[MineralMan]

1. Conspiracy theory stuff goes in the Creative Speculation Group.

Thanks for your cooperation.

[NightWatcher]

2. But what about conspiracy debunking?

I saw this live online and thought the same thing as the OP.

[MineralMan]

4. There has been a long tradition on DU of not posting 9/11 arguments

in GD. Why? Because they turn into complete disasters. Every freaking time. If it's a 9/11 discussion, it belongs in Creative Speculation.

[kcr]

8. Creative speculation belongs in creative speculation.

There is nothing creative about the truth. Debunking myths was never against the rules. You're wrong.

[genxlib]

59. You were right...

That this turned into a complete disaster.

But I will continue to bang my head against this particular wall.

Because...

1) I was there on a rescue mission and saw it myself
2) I am an Engineer and it is insulting to be told that I don't get it.
3) I believe all public discussion and policy should be based in reality and I will take our side to task for it as well as theirs.

Call me crazy but I can't help myself.

Nevertheless, I understand the general desire that this argument be banished to the woo dungeon.

[cwydro]

3. That was my first thought as well.

But I think the OP is trying to debunk a conspiracy theory.

It could have been worded better.

[NutmegYankee]

15. The impact of fire on steel structures isn't a conspiracy, it's engineering reality.

Hell, the impact of heat has been obvious to blacksmiths for over 3000 years. Basic engineering principles are NOT Creative Speculation, so No - I will not cooperate.

[7962]

39. Exactly. Heat DOES affect steel. Someone tell Rosie& the others.

It doesnt have to "melt" it, it only has to compromise it

[Blue_true]

85. Heat also dramatically weakens reinforced concrete. nt

[yardwork]

22. Maybe it's time to honor science and factual arguments.

The two extremes that meet in the middle -unapologetic ignorance of facts and fantasy-driven conspiracy theories divorced from fact - are the same two extremes that brought us Trump in the White House.

It's time for Americans to grow up. Start acknowledging facts and dealing with the real world.

Otherwise, our democracy is doomed. I'm serious.

[NutmegYankee]

23. +1000 nt

[Achilleaze]

26. 9/11 - another massive republican FAIL

de-freaking-plorable

[librechik]

5. apples and oranges.

and, yeah get an engineer. He'll explain why the two cases are not equivalent. (Psst-it has to do with gravity)

[genxlib]

12. I'm an Engineer...

...and I have no idea what you are getting at.

There are some key differences. Namely that the WTC were steel structures and this was a concrete girder bridge.

But the underlying principal is the same. Even though fire won't necessarily destroy a material (ie melt, burn). It can fatally weaken it to the point that it falls below the level of strength needed to do what it was designed to do.

[DemocratSinceBirth]

13. In layman's terms the planes brought em down.

[genxlib]

19. OK

I don't dispute the notion that the cause was different but I am just looking at the effect.

Certainly the building took some immediate damage that was a factor in the ultimate result. However, it was not a mortal wound. It remained standing while a fire burned to the point of collapse. This is even more true in WTC7 which did not get hit by an airplane but was doomed by fire completely.

My overall point is that a petrochemical fire can damage a structure to the point of collapse. In the case of 9/11 it was jet fuel. In the case of Atlanta it was plastic pipe.

[7962]

40. I knew I could count on at least ONE engineer to show!! Thank you.

I never understood why so many people think that steel has to actually melt before it could fail

[NutmegYankee]

49. Mechanical Engineer.

My job focus is more on fluid systems (pipes, valves, pumps, transducers, etc) than structural, but I have some structural experience from earlier work in the maritime industry.

[pangaia]

101. For Pete's sake, I'm a drummer and even I get it..

Thanks for your patience..

[librechik]

27. The highway pancaked once and hit the ground. The buildings each

had to pancake around 100 times, each time meeting zero resistance from the underlying cooler steel reinforced floors to fall down in seconds, like we saw.

Gravity made the bridge fall down. What caused gravity to fail 200 times (not counting tower 7 which even more graphically shows the collapse of sequential floors. )

I know, it was 800 gallons of kerosene! Which never gets hot enough to melt steel. Thank goodness, I'd have to throw out my camp stove!

[genxlib]

37. You are misunderstanding the physics

There is a fundamental difference between a static load and a dynamic load. (still versus moving)

If I understand correctly, you are suggesting that fire could have collapsed the floor at the site of the fire but the remainder of the building should have stayed intact. Sorry, that does not compute.

The "cooler" reinforced floors that you referred to were not trying to hold up the load they were design for. They were trying to hold up that load as it was falling. The gravity was accelerating the mass downward so that by the time it hit the floor below, it had a great deal of kinetic energy in addition to its weight.

To over simplify, the fire compromised floor failed with the normal load applied. The other floors were not fire compromised but were subjected to extremely higher loads due to the mass falling.

If you don't believe me, try this experiment. Take a weight that you can reasonably hold; say a 50 pound sack of flour. Then have somebody climb up on the roof and toss it down at you and see how successful you are at catching it. That same weight that you could hold "statically" would knock you flat on your ass after it built up 12' worth of falling momentum. It is the same for every subsequent floor of the WTC. It was trying to "catch" a falling load that it was only designed to carry statically.

For what it is worth, I am an Engineer with special connection to this subject. I am trained as a Structural Specialist with FEMA Urban Search and Rescue and have spent weeks in specialized training on collapse. I spent 10 days at the WTC after the event with a rescue team.

I get why it is hard to believe. But Structural Engineering isn't magic. It is defined by well understood physical principals.

[sarisataka]

38. In a large building

such as the WTC, what load would the column be designed to support over and above the anticipated maximum static load?

[genxlib]

51. It is risky to ask a nerd a technical question...

You may get more of an answer than you want.

In general terms, a steel structure would generally be designed for its anticipated load plus some safety factor.

In specific terms, that safety factor varies depending on a lot of things including the type of members, how they are used and the codes in effect at the time of design. For all practical purposes, a general rule of thumb would be about 50% more strength than required.

It is actually a whole lot more complicated than that. Like most things, the specifics can get buried in a whole lot of acronyms like AISC, ASD, LRFD, etc. I would love to go on but you would hate be for it.

Bear in mind, that safety factor is really to account for statistical variations to the basic assumptions (more load than anticipated, less strength than anticipated, bad welders, defects).

As a general rule, there really isn't any design parameters that account for that kind of falling load that I discussed in the post above. The normal safety factor that is inherent in design will help but it generally is not accounted for. Actual accounting for moving loads are generally limited to non-vertical loads such as wind and earthquake as well as literal moving parts like elevators.

In this specific building, I have read that the design did include the possibility of an airplane impact. Therefore they may have accounted for a dynamic load from a sideways kinetic impact. But that would not be the same as the downward force of the falling building impacting subsequent floors.

[sarisataka]

53. Thank you

My architectural knowledge is about nil.

I was trying so calculate some force of impact equations, ill remembered from long ago physics classes. It doesn't take much of a drop to get a lot of newtons.

Even from my very rough calculations I can see the structural capacity would have to be many time the basic load to withstand the force of even a single floor falling onto the one immediately below.

[genxlib]

57. Your welcome

It doesn't matter if you can calculate the specifics. Quite frankly it would take me a while to drill down to the actual numbers.

All it takes is a general understanding that moving loads have a great deal more effect than the static loads the building was designed for.

I am in the same boat on climate science. I have enough understanding of thermodynamics to understand the over-riding concepts and will leave it to those particular eggheads to calculate the specifics.

Having had any physics classes at all probably puts you ahead of most of these people who want to believe otherwise.

[DanTex]

60. Great posts. Except for one thing...

It's "you're" not "your"! (sorry couldn't resist)

[genxlib]

63. That's OK

You got me

My wife has an Masters in Communication and I have a know-it-all-teen daughter who is smart enough to be right most of the time. It is the price I pay for hanging with smart, free-thinking women. I wouldn't have it any other way.

I pride myself on communicating better that most Engineers but that still put's me at a disadvantage to the general population considering how piss-poor Engineers are as a group.

I love that video. Never heard that before. I saw Weird Al live at my college about 30 years ago. Hard to believe he is still doing it.

[Warpy]

76. You're doing just fine

It should be pointed out to the "why didn't it fail at just one floor?" people that there was a hell of a lot of weight above the failure point, the equivalent of a large 19 story building in the case of the north tower. Once that much mass got moving, nothing below it was going to stop it except solid bedrock, which is precisely what happened.

[7962]

80. Tanks for pointing that out. Another forgotten point. Or ignored.

I dont understand why so many feel the NEED for a conspiracy.
In a way, i blame TV & movies; they almost ALWAYS show a shadowy behind-the-scenes group in our own govt being responsible for whatever bad thing is happening in the movie

[Warpy]

90. That and a little learning being a dangerous thing

It doesn't take much more learning to see right through most of the paranoid theories, honestly, but it seems a lot of people just aren't willing to do it.

[Mean Gene]

61. Thanks for the explanation. Hadn't thought about all that. /nt.

[stevenleser]

95. What this exchange tells me is that some people will choose ideology over facts and physics no

matter what proof is shown. This is exactly how we ended up with an incompetent blowhard like Trump instead of someone who obviously could have done the job well and had the background for it.

Thanks for all the physics and engineering lessons. It's too bad those who are emotionally invested in a particular narrative won't yield to physical realities which are not subjective.

[GulfCoast66]

97. Well said

I wonder their feelings on Climate Change?

That is why I always remember that the left can like woo just as much as the right. Sometimes even more.

[pangaia]

102. Once again, even this dumb drummer even gets it. DUH !!

What is the matter with people?

Even I, an engineering ignoramus, have seen video of intentional demolitions of buildings (I imagine everyone has), and from what my eyes tell me, the explosions are at the BOTTOM, the bottom collapses and the rest falls-- The entire building just falls intact and crashes at the bottom, floor by floor.. bottom first, top last.

WTCs were the exact opposite..!! Top collapsed first, bottom last.

Did I get that right?

[Warpy]

108. Depends on the building, really

Some of them have explosives near exterior walls all the way to the top that aid implosion by reducing the ability of the external walls to prop up part of the building.

One thing I did when the conspiracy buffs were all out and hooting was do a lot of reading on controlled implosions. Most do start at the bottom, using the building's weight against itself as it pancakes on down. Structural walls in some of them do receive charges for the reason I suggested.

In my reading, I discovered how long it takes to drill into vertical support members, fit the explosive charges, and wire the whole thing together--and what a mess it makes inside the building when it's done. I also read about a lot of the abatement programs that need to be done in the US to reduce environmental contamination by asbestos and interior fittings that are toxic when burned or volatized. Obviously, none of this was done at any of the WTC, but you can't kill a conspiracy with facts.

[pangaia]

111. Interesting. I always learn new things here.

Thanks..

[Orrex]

126. Here's a nicely succinct rebuttal that I found a few years back

http://www.cracked.com/article_15740_was-911-inside-job.html

They don't get too tied up in the physics and instead go straight for the in-your-face realities of conspiracy management:

Even in a world where every structural engineering desk jockey is okay with mass murder, they're still not going to risk jail and career ruin and walk away from a huge book deal for ten grand. Oh, no, it's got to be millions, per person, just to make it worth it. Even a dedicated conspirator would need to know he or she was set for life.

Let's say they wrote 500,000 checks (hell, you've got more than 120,000 people in the American Society of Civil Engineers alone, and they'd be the first ones to speak out). Say the average payout was ten million (barely enough to live rich the rest of your life, but let's just say). So that's 500,000 times ten million which is...

...Five TRILLION dollars.

[ProfessorGAC]

116. Generally Speaking...

...charges are also place at higher levels to intentionally compromise structural support
This help the thing fall straight down. (That, plus in some implosion applications, low velocity devices are used to foment an updraft to increase the inward pressure a bit)

[pangaia]

117. Thanks, Prof. I learned even more....

And just for a thankful 'payback,' the only time Ravel ever used a whole-tone scale, as far as I know, was in his first published piece.


Cheers,

[ProfessorGAC]

138. Whole Tone Music

Always attracted to the unusual character that has.

[WillowTree]

103. One small (?) change to what you said that I rarely see acknowledged.

You said ".......the fire compromised floor failed with the normal load applied". But I almost never see anyone mention that the "normal load" for one of those floors almost certainly didn't anticipate the addition of the weight of a Boeing 767 aircraft. Wouldn't that have had a significant effect on how much the structure at the crash floor(s) would have needed to be weakened before they gave way?

I'm in software development, so what do I know? But I was married for a log time to a structural engineer and just from the little that I absorbed from him, it would seem that the weight of the aircraft would be something that should be included in the equation.

[genxlib]

119. You are correct

But probably not as big of an effect as you might imagine. There are several mitigating factors.

For one, a portion of the crash debris went straight through the building and ended up in the streets and rooftops beyond. Also, the crash site actually enveloped multiple floors so that debris would not have been concentrated on one level.

Even a large load spread over a large area would be a relatively low increase. The max weight of a plane (~400,000 lbs) divided by the area of one floor (~40,000) is only 10 pounds per square foot(psf). Divide it further over multiple floors and it drops to a relatively small number considering the building was probably designed for 50-100psf

Beyond that, generally speaking buildings are never really loaded to their assumed capacity. The nature of design assumptions requires load levels be considered for relatively high usage. Maybe not what you would consider worse case scenario but certainly on the high side of average. You might have particular areas within a building that gets fully loaded (say a file room) but generally speaking, buildings have some fraction of their total capacity in use at any given time.

Perhaps more significant is that those floors at the crash site were no longer configured as intended. Some percentage of structural members were severed, others would have lost fire proofing, others would have been mangled out of shape.

What it boils down to is that a structure is designed with a certain number of variables either fixed or operating within a controlled range. A plane crash changes dozens of those variables in ways that are much more complex than a simple blog discussion can tease apart.

[genxlib]

54. Even more

I stand by my original post above but I am going to go even further in an effort to explain why it can happened the way we witnessed.

The major thing that is often missed in discussions about building structures is that they are interdependent systems. All of the members interlock to create a frame that collectively does the work. In a simple building frame, the columns support the beams and the beams support the columns.

I think the first concept (columns support the beams) is self explanatory but it might be less obvious how the beams support the columns. All else being equal, a columns strength is directly related to its length. A short column is stable but a long column gets noodely and can buckle (think of a straw). In a building, the beams are used to brace the columns at each floor to counteract that buckling effect.

When the floor structure at the level of the crash was demolished by the impact and subsequent fire, it left the columns in those areas unsupported. Their effective length suddenly doubled and may have even tripled or quadrupled. Basic structural engineering shows that the load carrying capacity of longer columns drops off precipitously. Therefore, the columns could have easily been overstressed even without fire impacts depending on what happened to the floor structures that were stabilizing them.

Which leads me to my next point which is actually probably the most direct explanation of your question. For the sake of argument, lets say we are talking about the crash site being at floor 100 out of 110 floors. At that location, the column is designed to carry 10 floors worth of load, right? But the floor system is only designed to carry one floor's worth of load because only one floor is sitting on those beams.

So when the top ten floors fell, they were no longer supported on the columns. All that weight landed on the floor below. So you had 10 floors of weight sitting on a floor designed for one. Being overloaded by a factor of 10 would overstress the beams and collapse.

In fact, this is actually borne out in the debris field. The columns were not generally crunched, they fell away pretty much intact when they were no longer held in place by the pancaking floors. I have pictures if you want to see them.

So even if you remove the dynamic effects completely, collapse would still happen. The floors are not individually designed to hold all the wait above them.

[Dem2]

78. Thanks

Simple and logical.

[EX500rider]

73. "I know, it was 800 gallons of kerosene!" No, it was 10,000 gallons of jet fuel...

800 gals? It was 2 fully loaded 767-200's.

And how hot does every single thing on several floors of a office building burn at?
And how hot does steel have to get to bend, not melt?

[Dem2]

77. I'm an engineer

And this analysis embarrasses me.

[librechik]

31. excuse me, what made the rest of the 100 plus floors not touched by fire fall??

3 buildings, localized fires on certain floors, the builsing disintegrates all the way down from where the fire is, including the steel structure. What made that happen?

Th pancake theory is obvious in the Atlanta Highway incident. What made the rest of the building collapse after the first one or two pancaked due to fire?

[7962]

41. Its called physics.

When you fall down on the floor how hard do you hit? If you fall from 10 feet high, how much HARDER do you hit?
Or drop an egg from 1 inch and 1 foot. Egg weighs the same, yet the results are different
The lower floors couldnt withstand the force of the upper floors slamming down. And with each floor, the force grew larger.
Understand now?

[librechik]

52. except force doesn't increase as it hits obstacles like steel reinforced concrete floors

each reinforced level would absorb the force exerted on it. At some point the ferroconcrete would fail to pancake because the energy of the initial pancake was disipated. Sure the egg could fall 100 floors and get faster and faster--but if you put a plate in front of it at floor 78, that would be the end of the egg.

[genxlib]

55. Please see post 54

It is the direct answer to this specific question.

You are right that some of the dynamic energy would be absorbed by the structures below.

However, it is incorrect to say that the pancake would stop.

Each floor is only designed to carry itself. The cumulative weight of every floor gets added to the debris as it collapses. So the second floor has double the load, the third floor has triple the load, etc.

Even if the dynamic effect can be completely discounted, the shear weight of debris sitting on each subsequent floor would continue the collapse.

[genxlib]

64. More to your point

I realized there was an even more relevant point to make regarding your direct question.

You are assuming that the subsequent floors will absorb energy and eventually stop collapsing.

What you are missing is that the falling mass continues to gain momentum.

Let's say floors 100-110 falls onto floor 99, it will have traveled one floor's worth of distance (for arguments sake lets say 12')

Then for the sake of your argument, that floor absorbs almost all of the energy but still fails. Then you have floors 99-110 falling ANOTHER 12'. Therefore, it gains back all of it momentum and then some because there is even more weight in the falling mass.

Carry the chain farther down into the building. At floor 60, you have 50 floors of mass falling another 12'. At floor 30, you have 80 floors of mass falling another 12'.

The chain of collapse will continue because every floor gets impacted by a moving mass that grows larger as mass gets added to it.

The flaw in your logic is that you are thinking of it like a bullet that starts with a certain amount of momentum that can be slowed as it passes through resistance. In this case, gravity continues to work and is continually adding momentum back into the system.

I hope you are able to see. Those subsequent floors did not stand a chance of stopping this collapse.

[snooper2]

120. This is why stupid consipiracy theory crap is relegated to the dungeon

Can I introduce you to a YouTube channel that will convince you the earth really IS flat? Lots of evidence

[Aristus]

6. But steel doesn't melt! Steel has never melted in all of recorded history!

I love Rosie O'Donnell, but that was some crazy-ass shit she was spewing...

[Laffy Kat]

10. There are people who actually think steel doesn't melt?

How do they think it became steel to begin with?

[Aristus]

16. Who the fuck knows?

It's akin to saying: "But planes have never been hijacked! No one has ever hijacked a plane in all of recorded history!"

[yardwork]

20. That is mind boggling!

Lol. Do they think that the steel girders are discovered buried in the ground, to the exact specifications required for each project?

[7962]

42. THANK YOU!!! I was never aware of a "steel beam mine" nt

[KingCharlemagne]

11. Steel melts, IIRC, at 1600 degrees F. At 1200 degrees F (the maximum temperature

burning jet fuel reaches), steel will not melt per se, but it will weaken to the point where it is structurally compromised.

[librechik]

34. actually it melts at 2750 degrees if you are talking Farehrenheit

and we need a furnace and oxygen blast to achieve that.

[Orrex]

127. And it retains all strength and rigidity right up until it reaches 2750 degrees?

[NutmegYankee]

17. Steel doesn't need to reach melting temperature to become soft.

The strength of steel declines with temperature, eventually becoming soft enough to bend by hand as though it was clay, but it is still a solid and has not melted. Most old time blacksmith forges couldn't get hot enough to melt iron, but the temperature was high enough to allow them to work (forge) the iron into the needed shape.

[Aristus]

18. I agree.

I was just mocking the 9/11 Truther nonsense...

[NutmegYankee]

21. My sarcasm meter is a bit broken today.

My humor dropped off as I look out the window at the April fool's joke Mother Nature is playing on us. Snowflakes... *sigh*

[librechik]

29. 247 times--all the way down all three WTC buildings

The bridge melted and smacked into the earth.

What made the floors fall under the fire point? They weren't "weakened" by fire.

[NutmegYankee]

36. Overload.

Last edited Sat Apr 1, 2017, 02:34 PM - Edit history (1)

Once a large mass gets moving, it's kinetic energy can easily overload the columns below. The building above the failure point was just such a large mass.

Basic obvious physics. The columns fail by buckling.

[librechik]

28. steel doesn't melt at 860 degrees, the hottest jet fuel gets without a furnace to help

Go ahead, laugh. No one ever said what you claim.

[7962]

44. Sorry, but jet fuel can burn up to 1500F. Google is your friend

Not to mention the added fuel of all the other stuff burning

[Hokie]

7. I thought about the 911 Troofers too

The bridge collapse demonstrated once again that a fire doesn't have to be hot enough to melt steel to cause it to yield under load.

[KittyWampus]

9. The engineering involved in the two is so different that it's comparing a dog to a tree.

Both biological wonders of engineering. But both very different taxonomic structures.

[kcr]

14. Fire weakens structure. Structure collapses.

The two structures were indeed different, but basically the same thing happened to them.

[panader0]

24. What brought the other building down?

[JimGinPA]

47. Most likely it was the plane that hit the second tower

[Blue_true]

86. Both buildings were hit by a plane near the building top.

Both buildings had the same external support structure and were prone to collapse if the upper floors started to collapse (which they did after being burned out be the jetfuel).

[panader0]

89. Three buildings fell. One was not hit by anything.

[EX500rider]

132. What makes you think it wasn't hit by anything?

Many conspiracy theorists point to FEMA's preliminary report, which said there was relatively light damage to WTC 7 prior to its collapse. With the benefit of more time and resources, NIST researchers now support the working hypothesis that WTC 7 was far more compromised by falling debris than the FEMA report indicated. "The most important thing we found was that there was, in fact, physical damage to the south face of building 7," NIST's Sunder tells PM. "On about a third of the face to the center and to the bottom—approximately 10 stories—about 25 percent of the depth of the building was scooped out." NIST also discovered previously undocumented damage to WTC 7's upper stories and its southwest corner.

http://www.popularmechanics.com/military/a6384/debunking-911-myths-world-trade-center/

[NutmegYankee]

25. If you look closely below, you can see the steel I beams that support the deck.

Link to tweet

/photo/1

Same failure mode - fire weakens steel and structure collapses. This has happened before in several places. A tanker truck fire in 2004 buckled I-95 and led to a closure for weeks.

[genxlib]

43. One possible difference

We are on the same side trying to get people to believe basic science (see post above).

However, it looks to me like those were concrete girders in that bridge collapse. I am familiar with bridge structures but not that one in particular. But if you go to google earth, all of the views that I can see look to be prestressed concrete AASHTO I beams. It could very well be a hodge-podge of various structure types that have been used in various widening projects so there could be some sttel beams on the inside spans.

Either way, the principal is the same. Fire can weaken a structure to the point of collapse.

[NutmegYankee]

45. You're right.

As I look at closer photos, it is prestressed concrete.

[WinkyDink]

30. Burning jet fuel has a specific temperature. It does not reach that sufficient to turn REINFORCED

steel to collapsing heaps of dust.

[Major Nikon]

65. Complete nonsense

"structural steel begins to soften around 425°C and loses about half of its strength at 650°C"
-- Fire Protection Handbook 17th Edition (Quincy, MA: National Fire Protection Association, 1992), pp. 6-62 to 6-70

[WinkyDink]

92. Even the compromised "Popular Mechanics" only goes as far as claiming the steel columns would

"bend."

Except they didn't. No bending, no swaying, no sideways falling-over.

As we all saw, the building collapsed straight down onto itself, as in a controlled implosion (just saying the resemblance in undeniable).
And no jet fuel of any degree ignited WTC 7.

[Major Nikon]

93. No doubt PM is part of the conspiracy

[GulfCoast66]

96. you must be kidding me??

You think that if the steel making up the towers were to bend and to lose the necessary rigidity that the building must 'bend' and could not possibly fall straight down?

Holy cow, this is 10th grade science. Gravity. Once the structure fails, the quickest way down is straight down. Why in the hell would it go sideways?

[snooper2]

121. Yeah, Popular Mechanics sold out a LONG time ago- 1936!

With this bullshit Charting Storms by Radio...

https://ia801303.us.archive.org/BookReader/BookReaderImages.php?zip=/9/items/PopularMechanics1936/Popular_Mechanics_01_1936_jp2.zip&file=Popular_Mechanics_01_1936_jp2/Popular_Mechanics_01_1936_0058.jp2&scale=8&rotate=0

[WinkyDink]

136. And the NYT printed that Saddam had WMD's. Your point?

[EX500rider]

74. What's "REINFORCED steel"?

When they reinforce concrete they use steel.
What are you suggesting they reinforce steel with-in 1975 when the Twin Towers were built?

[Blue_true]

87. There are many grades of steel.

The steel that reinforced concrete is a lower grade than is used for lateral and vertical support beams. Reenforced steel from early days had other metals added to iron, different combinations produced different levels of strength. Today, carbon fiber is being more to make reenforced steel due to it's very high strength/weight ratio.

[WinkyDink]

91. My father worked for Bethlehem Steel. Titanium, e.g., is added to strengthen steel.

[GulfCoast66]

98. WTF is reinforced steel?

Or does REINFORCED concrete get stronger if you spell it in all caps?

Because I sometime work with reinforced concrete. And the concrete is not the weak point. It is the steel inside the concrete which make it reinforced concrete that is always the failure point.

And I will be the first to admit that while I work with concrete and steel, I may be ignorant to the existents of reinforced steel. Please enlighten me.

[genxlib]

128. Just for fun...

Allow me to elaborate.

It is true that steel inside the concrete is the failure point (ie the "weak point" in your statement)

However, this is entirely by design. In reality, steel is much stronger than concrete and has the advantage of working in both tension and compression. Concrete on the other hand is relatively weaker and is only really effective in compression. It's tension capacity is limited and unreliable.

Together the two make a good team because reinforced concrete takes advantage of both materials "strengths" (pardon the pun)

When designing reinforcing concrete, the balance between those two materials is always set so that the steel fails before the concrete. It would be easy to provide enough to steel for the concrete to fail first but it is never done.

The reason is that steel failure is ductile so it fails by stretching out. Concrete failure is brittle so it fails by breaking suddenly.

In layman's terms, it is the difference between having time to see a failure and get the fuck out from under it.

[Warpy]

109. It does reach a temperature sufficient to soften it

especially when combined with all the interior materials of that building which it set afire.

[Achilleaze]

32. For anyone who still swallows the official republican Fake News talking points

[librechik]

33. lol--so true.

but people that don't believe the Bush official story are persona non grata everywhere, especially here.

I don't know what happened there, it could have been a raygun attack from the Imperial whatever those things are. But I know the 9/11 commission lied. Their own lawyer said they did.

https://www.reddit.com/r/911truth/duplicates/8cgih/911_commission_counsel_government_agreed_to_lie/

[Kentonio]

62. What I don't get is why you need it all to be a lie.

What's so hard about believing that ok there was some weird shit going on with the Saudi connection, but at the same time the buildings just collapsed because buildings really aren't built to take a jet liner collision?

Over and over again engineers of all political leanings say the say things explaining how this happened, and over and over again people like yourself tell them their science is wrong. It's embarrassing.

[librechik]

66. I don't fucking "need" anything but the facts.

That is all.

[Kentonio]

69. Engineers keep giving you the facts.

It's physics, it's not subjective.

[7962]

83. Brilliant & right to the point. Thanks nt

[whistler162]

88. I will stick with my source thank you......

[7962]

70. But you're choosing "fake facts" over actual FACT.

Such as the temps of burning fuel, the effect heat has on the strength of steel, gravity, etc

[EX500rider]

75. here, I will help you out:

the facts:

Debunking the 9/11 Myths: Special Report

The following content is from an in-depth investigation of the conspiracy theories surround the attacks of 9/11, which was published in the March 2005 issue of Popular Mechanics.

http://www.popularmechanics.com/military/a49/1227842/

Or is Popular Mechanic's a CIA front? lol

[7962]

81. Any fact that doesnt support the theory is said to be "faked by the CIA"

I suppose that even includes the damage done by the jet on the way into the pentagon. Since that was supposedly a missile instead of a jet.

[Jonny Appleseed]

105. Go rewatch the South Park episode

[yurbud]

35. 28 pages showed Saudi intel agents helped and funded hijackers

Which blows the official story to pieces since government claimed everything after 9/11 was to fight terrorism, but Saudi was left untouched without even a hiccup in our relationship.

[7962]

46. You dont have to be a republican to understand physics.

Yes, a lot leading up to 9/11 was missed/ignored/not acted on. But the incident itself happened the way the whole world saw it happen.

[NutmegYankee]

50. The Democratic Party is supposed to support science.

The science denying crowd frankly doesn't belong here. And they have the gall to call us republicans. It defies words.

[anneboleyn]

56. That AT-AT is like ten times taller than the normal Walkers. It's legs would be exceptionally long

and therefore very weak (and the body very off-balance) based on the size of all the buildings around. They also don't have that kind of firepower. Yes I am a Star Wars nerd.

[uponit7771]

94. lofl

[LanternWaste]

130. I too mock people who place more faith in physics than in my own allegations.

I too mock people who place more faith in physics than in my own allegations. Adding the Star Wars reference and Fake News only reinforces the depth of your alleged knowledge.

May the schwartz be with you...

[Squinch]

58. Made It Happen On Purpose? WTF?

Are you saying you think this was a false flag or inside job?

[Achilleaze]

67. Made what happen?

The wholesale onslaught of Fake News, republican style?

[LanternWaste]

131. What you lack in objective facts is more than made up for in unsupported allegations...

What you lack in objective facts is more than made up for in bemusing memes and unsupported allegations... no doubt, the mark of all good research. I empathize... college courses can be hard, and sometimes we place faith in magic to make the world seem less scary.

(insert rationalization below... with additional memes if necessary)

[Achilleaze]

134. What you gain in subjective fancification is more than diminished in supported non sequiturs

[7962]

71. Yes, there are whole groups dedicated to that line of nonsense;

they call it "MIHOP" It has been brought up here on DU MANY times back in the old days.
Its still equally ridiculous today, yet still has believers.
Yes, people missed &/or ignored warnings. I remember reading about hopes of Islamists to fly planes into buildings back in the 90s. I laughed, thinking "yeah, right, they'd never be able to pull off something like that". Some in govt likely felt the same way, but they had the responsibility to take it seriously

[Squinch]

72. That's Jackpine Radical level of crazy!

[GulfCoast66]

99. Got any examples of the Islamist flying planes into buildings thingys that you read?

I would love to see your sources. Because I kept up with the news back then and when 911 happened I was shocked.

And remember, it could not have been online, because there was no online back then. So it must have been published journals or papers I could look up.

So please, send me your sources, I would love to see them. Even if you are not sure where you read it, there were so few possibilities back then it should not take me long to hunt them down.

thanks.

[7962]

112. It was well after the 1st attack on the WTC. A couple stories I had seen on TV;

the closest thing i can find now is this mention from CNN.
http://edition.cnn.com/2002/ALLPOLITICS/09/18/intelligence.hearings/

I think i remember a show on History channel in the 90s that was recapping the 1st attack bringing it up similar to the CNN story.

[egduj]

68. I think a missile brought the bridge down.

[7962]

82. Oh lord, that'll really bring 'em out!

Noooooooooo

[GulfCoast66]

100. Bullshit

Everyone not in the grasps of the illuminati knows it was Chemtrails.

[Warpy]

110. Some people just want to watch the world burn

[obamanut2012]

115. Just stop with your ridiculous conspiracy theories, okay???

There is no place for that here.

We all know it was lizard people.

[snooper2]

122. It was actually weakened by urine from homeless folks who lived there

You will see the war on the homeless ramp up even more now

[Dem2]

79. I saw this coming.

http://www.democraticunderground.com/?com=view_post&forum=1002&pid=8874983

[Blue_true]

84. From what I understand, the main issue with the old WTC

was the support structure design. The buildings had an exoskeletal support structure, when jet fuel burned up the upper floors and they started to collapse, they created a chain reaction where lower floors were pulled down due to the support structure being pulled in and down.

High heat embrittles concrete structures, including support pillars and beams.

[beam me up scottie]

104. This thread brings back memories.

Makes me miss the good ole days on DU when we thought Bush was the worst thing that ever happened to our country.

LIHOP/SCHMIHOP - it was HOLOGRAMS, SHEEPLE!!!









I shouldn't need this but that was

[Jonny Appleseed]

106. I think that this election cycle showed us that we have no aliens or CIA blackout squads

9/11 being a false flag would take a degree of secrecy that is impossible given how we've been observing how our intell agencies act when we're attacked and it's being lied about, and this one didn't even physically kill people.

[7962]

113. Precisely nt

[jesskirablue42]

107. follow the money

While everyone else is concerned about structural and engineering issues..

I just have two words: put options. that is all.

conspiracies happen whenever more than one person is involved in something, so yes, they are real. They just aren't what people are led to believe they are.

[7962]

123. If you're trying to refer to shorting airline stocks, another overblown failure.

Short activity leading up to 9/11 was not unexpected, since AA had just released bad earnings & United was expected to do the same. Its easy to find tracking of puts before earnings calls prior also; which would also show increased activity. just as it would in any other stock you'd bet on having a bad report

[Demsrule86]

114. They are charging a homeless guy...I call bullshit.

I used to live near Atlanta...they use private companies for the roads now...my nieces husband used to make good money...but that state is shit now. The company is at fault I would bet on it, and they are railroading this guy in order to hide the truth...most of the private firms have ties to the Georgia state government...which is completely corrupt.

[Orrex]

118. The bridge was brought down by an implosion bomb.

[stevenleser]

124. Micronukes to be precise. Either that or a directed energy weapon of some sort.

[Orrex]

125. Finally a voice of reason!

[EX500rider]

133. Now, now, we all know it was micro thermite plasma charges!

[NCTraveler]

129. They aren't even good conspiracy theorists. That's how fucking dumb they are.

This should be in creative speculation. All things on this matter should go there. Debunking such foolish conspiracies should be put on the same field as the conspiracies themselves.

I have never met one single person who buys into this shit. I guess that is a positive statement on those I surround myself with.

This op, in itself, is a conspiracy.

[WinkyDink]

135. SOOO not apples to apples. OMG.

[7962]

137. You should read some of the posts above from actual engineers

Folks who can see the comparison and understand it.
Thats why I mentioned scaling the two.
If anything, the WTC collapse is MORE understandable considering the huge impact of the airliners