Fire weakens steel to collapse SF bridge.

Originally posted by squidbones
i saw video of the fire. This is very relivent to the 9/11 conspiracy debate, mostly in that it proves that fire can melt the steel. I do not know if there was an initial explosion from the truck but the driver did surrive. What I find most interesting is the pre colapse footage, you can see the thing sag like mad.

Probem with your theory is that NIST and FEMA state that the fires in the towers was not hot enough to melt steel, only weaken it. Basicllay all you had was an office fire after the jet fuel burned off.

Originally posted by squidbones
i saw video of the fire. This is very relivent to the 9/11 conspiracy debate, mostly in that it proves that fire can melt the steel. I do not know if there was an initial explosion from the truck but the driver did surrive. What I find most interesting is the pre colapse footage, you can see the thing sag like mad.

The collapse is comparable to that of a 90+ story building coming down. When the stories started to come down on 9/11 the buildings steel was weaked by fire and the force of the building broke them. It would be like a building made of spagetti, and you put it in boiling water and it collapses. Steel melts. We now have proof. Finally.

How long untill some one says that the whole thing was a set up by the gov to descredit the 911 truth people.

This thread is so full of hilariuos analogies anf false proofs I have no where to even begin... "Buildings of Spaghetti"? You do not know the definition of MELT. SAG = Weakened... FLOWING LIQUID = MELTED.

Sweet mother of mary... yesterday someone called all the CTers here "pseudo-physicists" and laymen... I will link this post the next time that is brought up.

I think Alex Jones ripped me off... JERK... notice there is no TIME on his "publication":

www.prisonplanet.com...

The mechanism of the bridges collapse is heat expansion, and not weakening of the steel.

You can not compare this to 9/11..in any way shape or form!

Now I am not sure of the composition of the actual material that this roadway was constructed of but...asphalt is applied at high temperatures and then allowed to cool and form a roadway. When that asphalt is heated it turns to a pliable state (for lack of a better term) and is easily moved and does not support much weight, especially suspended. I have a bucket of road patch for my driveway and to use it all you have to do is set it in a sunny place and you can fill in about any hole or dent you want...just an observation.

edit: Don't know if this is a concrete or asphalt roadway...anybody know?

[edit on 1-5-2007 by DagoTime]

These bridges are constructed by laying steel reinforced concrete beams on top of the concrete columns. After the beams are added a steel layer is placed onto the beams and then a layer of concrete is poured onto this foundation. The final concrete roadway may or may not have asphalt on top of it but that would just be for wear and tear absorption. All of the main support is from steel and concrete. Expansion joints are added in after the concrete support is in place. They have little to do with the actual bridge integrity. They just keep the roadway , the thin top layer of concrete from cracking when it gets hot. By thin I mean in comparison to the girders that this layer rests on.

The surface of the bridge rests on concrete girders.



Obviously the girders were weakened by the heat. That's fairly amazing when you realize that these things are probably between 3 and 5 feet thick. The only way to knock down a section of the bridge would be to destroy a column or the girders. The top section of the bridge is just there so you won't fall between the girders when you cross.

[edit on 1-5-2007 by dbates]

Thanks DBates.

One thing though. Here is a pic from a different thread:

Originally posted by FredT

Notice how the failure is along the expansion joints (both sides). Can you find a detail of a composite bridge with an expansion joint shown? That would help. I don't design bridges nor roadways, so this is not my expertise.

Also, notice in the intact roadway in the background, you can see gaps in the girders where the expansion joints are. You can also see that this is the area where the failure happened.

I asked this in another thread but didn't really get an answer:

If we can compare what equates to a road to the towers, does that mean we can compare other skyscrapers to the towers yet? Who here is ready to do that?

I've seen bridges like that collapse on their own.

I have yet to see a Skyscraper collapse on its own. Point being, there is no comparison.

bridge like that collapesed in Montreal last year
exactly
I have never seen a skyscraper fall
I have seen bridges fall.
no fire needed

here is the basic link to the bridge = the towers fallicy

www.infowars.com...

[edit on 1-5-2007 by junglelord]

Originally posted by bsbray11
If we can compare what equates to a road to the towers, does that mean we can compare other skyscrapers to the towers yet? Who here is ready to do that?

I was wondering when this would be brought up. Think about it. They want to compare:

-a 2000 degree hotter fire.
-concrete and asphaltic structure
- beams as oppossed to columns

Yet we can't compare the Windsor tower inferno to the WTC?

Originally posted by junglelord
bridge like that collapesed in Montreal last year
exactly
I have never seen a skyscraper fall
I have seen bridges fall.
no fire needed

here is the basic link to the bridge = the towers fallicy

www.infowars.com...

[edit on 1-5-2007 by junglelord]

The bridge that fell in Montreal last year was due to faulty maintenance. Since we have really messed up weather (from very hot to very cold frequently) and extremely cheap and crappy roads, they need to be maintained alot more frequently. They neglected to do so despite huge cracks in the structure and hence it collapsed.

Griff

Exactly, they don't want comparison's to any other building cause "9/11 was a unique day"! Yet a highway, they are ready to jump on.


Yet avoid when the Empire State Building got hit by a plane

There is a major difference in the bridge collapse and the WTC.
Jet fuel burns much lower than natural gas and other types of fuel. Jet fuel burns at about 500 to 600F. Natural gas, etc. burns at app. 3,000F or so.
The jet fuel wouldn't have been hot enough to melt the towers, but it wasn't jet fuel that was on the bridge collapse, it was regular fuel and could burn at 3,000F to 3,500 F, hot enough to melt the concrete, which also collapses at those temperatures.
Also, if it had really melted, it would be glass, but it wasn't.

en.wikipedia.org...:Jet_fuel

"After jet fuel is ignited, what temperature does it burn at in standard conditions? It states right here in wikipedia that in open air jetA burns at 500 to 599 degrees F. I am a diesel mechanic and a welder/fabricator, and have first hand experience with most of the factors that are said to have caused the collapse of the twin towers. Being a fabricator and knowing how hot I have to get steel to get it to weaken and bend, I can tell you with certainty that if wikipedia's figures are correct, 600 degrees F is not hot enough to weaken steel, especially the massive steel used in the twin towers."

IMPORTANT: This section of the road was the part that was not reinforced after the Loma Prieta earthquake, meaning it was already in a weakened state.

Originally posted by talisman
Yet avoid when the Empire State Building got hit by a plane

But, they will say it's concrete and concrete does better in fire. Does it? This bridge shows that it doesn't.

Either we can compare concrete to steel or we can't. We can't pick and choose when it can be applied either.

Here's a side-view that shows the placement of an expansion joint. Again, the expansion joint in this type of bridge has more to do with creating a smooth transition between sections and very little to do with actually supporting any load. The girders resting on the columns are what supports the load.

The top bridge in this image show the typical expansion joint.


I'm not an expert at these bridges, but I've been driving alongside the construction of a 6 lane toll road every day for the last 2 years. I've seen these bridges built from the ground up. The columns have steel rods that pertrude from them that the girders are fastened to. These rods simply keep the girders from moving side-to-side. Even without the steel rods, the girders would sit on the column without falling. The only way these could have fallen is if the concrete girder sagged or the columns were damaged allowing the girders to slip off of one side.

Construction photos

[edit on 1-5-2007 by dbates]

All this shows is that steel encased in concrete is weakend in a sustained fire. This is a comparison at best but it should be observed since the WTC had inches of concrete, and we all agree the steel was weakened, and not melted.

As far as Windsor, if it was constructed in the same was as the WTC it would be applicable, but until we can find another building designed the same and look for fault, there is nothing to set a precedent other than the collapse on 9/11. This is a shame.

Has anyone ever looked into the blueprints for the building in Seattle designed the same way? If those were not available, i would suspect coverup. just my 2 cents.

similarity, coincidence and precedent. Three frightful words on 9/11 research.

Even by your own pictures, there is a gap in the girders at the expansion joint. How can this have the same strength as the rest of the girder? Plus, it's not a matter of the steel weakening, it's a matter of the steel and concrete expanding beyond the capacity of the jont and failing at the joint. The bridge failed at the expansion joints, period. You can see this in every picture posted about it.

[edit on 5/1/2007 by Griff]

The girders are not supposed to touch. You always have a gap between them to allow for expansion. The expansion joint exists to allow for expansion in the concrete of the overlying roadway. They are not necessary for the girders to stay in place. Some of the rubber is missing in the expansion joints on the bridges I drive over every day. If traffic is backed up I'm stopped in the middle of the gap some times. The gap is probably just big enough to get your foot caught in. You wouldn't actually fall through but it is a bit spooky since it's about 80 feet to the ground.

The road I'm referring to:



I think you're misunderstanding the concept. each column supports the end of two different girders. The only possible failure a bridge can have is if the girder or column failed. If you remove all the expansion joints you might have a rough ride over the bridge but it won't cause any part of the roadway to fall.

Take the above photo for example. The columns are positioned to support the place were the girders meet. The girders do not touch each other. I can see the gap between them every day on the way to work.

More construction photos



[edit on 1-5-2007 by dbates]

Originally posted by esdad71
All this shows is that steel encased in concrete is weakend in a sustained fire. This is a comparison at best but it should be observed since the WTC had inches of concrete, and we all agree the steel was weakened, and not melted.

Funny, its ok to compare a bridge to the towers but not other steel buildings.