Buckled Structural Steel in Building Fires

[MikeC]

FYI.....a fire in a corner of an office tower in Auckland New Zealand overnight has left some stark pictures of steel buckled from the heat ....with no kerosene involved - eg

 

[SmokeHillFarm]

FYI.....a fire in a corner of an office tower in Auckland New Zealand overnight has left some stark pictures of steel buckled from the heat ....with no kerosene involved - eg

Interesting, but with only these photos it's hard to tell whether this is actually structural steel, or perhaps just some part of the window trim on the exterior, which is commonly made of some aluminum alloy and is not truly load-bearing. I lean toward the latter, primarily because it seems mighty thin to really bear much load -- but that's strictly a guess.

Whenever I'm dealing with some Truthie Cult zealot who talks about temperatures and steel "melting," I just point out that the manufacturers of structural steel consider 550 degrees F. as the FAILURE POINT of their product. This is from the AZO Build website, the largest manufacturer of struct. steel in Europe:

"Strength loss for steel is generally accepted to begin at about 300ºC and increases rapidly after 400ºC, by 550ºC steel retains about 60% of its room temperature yield strength. This is usually considered to be the failure temperature for structural steel."

Link: http://www.azobuild.com/article.aspx?ArticleID=3621

Obviously this is WAY below the melting point of steel, showing that steel just has to SOFTEN, not "melt."

As the link points out, this temperature varies considerably if insulation is present or if the steel itself is inserted in concrete. In the WTC case, we know the insulation was knocked off and that most of the steel in the fire zone was "bare."

 

[Trailblazer]

Interesting, but with only these photos it's hard to tell whether this is actually structural steel, or perhaps just some part of the window trim on the exterior, which is commonly made of some aluminum alloy and is not truly load-bearing. I lean toward the latter, primarily because it seems mighty thin to really bear much load -- but that's strictly a guess.

Whenever I'm dealing with some Truthie Cult zealot who talks about temperatures and steel "melting," I just point out that the manufacturers of structural steel consider 550 degrees F. as the FAILURE POINT of their product. This is from the AZO Build website, the largest manufacturer of struct. steel in Europe:

"Strength loss for steel is generally accepted to begin at about 300ºC and increases rapidly after 400ºC, by 550ºC steel retains about 60% of its room temperature yield strength. This is usually considered to be the failure temperature for structural steel."

Link: http://www.azobuild.com/article.aspx?ArticleID=3621

Per your link, that should be 550 degrees C, not F (550ºC = 1022ºF). Still far below the melting point, of course.

 

[SmokeHillFarm]

Per your link, that should be 550 degrees C, not F (550ºC = 1022ºF). Still far below the melting point, of course.

You're quite right, of course. It's hard to keep the mind focused when posting at 3 a.m. ....

I should also point out that they state that steel BEGINS to lose measurable strength at only 300 C, which is about 570 F. And of course most office fires, especially when not fought at all, reach 1000 F or more very quickly.

 

[econ41]

You're quite right, of course. It's hard to keep the mind focused when posting at 3 a.m. ....

I should also point out that they state that steel BEGINS to lose measurable strength at only 300 C, which is about 570 F. And of course most office fires, especially when not fought at all, reach 1000 F or more very quickly.

The engineering aspect often missed by "truthers" and "debunkers" alike is that the role of temperature in collapses such as the cascade failure of the initiation sequence for the Twin /Towers is of "last straw". It is NOT the sole cause of failure.

It only needs ONE column - possibly already overloaded due to load distribution following the damage of aircraft impact - to be further weakened just that little extra so it fails - and releases its own load to redistribute.

The only column needing the effects of heat at any stage is the NEXT column to fail.

There may be many more nearby columns affected but,...

The key error of most truther claims lies in the assumptions that ALL columns need heating to failure as if they had no existing loads applied.

Far from the true situation.

 

[Oystein]

Truthers also tend to forget that it is extremely difficult to build tall structures such that they don't collapse at all, and even harder to make them resist fires and not collapse. The higher you build, the more difficult - which is why the few engineers and architects capable of doing this get stinking rich. Instead, truthers seem to believe the higher ypu build, the more difficult it gets to make them collapse. They must think that if you build 2 miles high, that cannot ever collapse for any reason at all.

And yet, so much depends on details of code and workmanship.

An anecdote - something that was on the news here in Germany several years ago:
There were wild fires in California that set a number of mansions of the rich and famous in Malibu ablaze. One picture became famous: A sole mansion standing, apparantly untouched, in the midst of an expanse of lots with totally burned down, charred and flattened former buildings. The story here was that this mansion was built and owned by an star architect (of Japanese descent, iirc) who was a fan of German building code and had built it accordingly (in addition, I presume, to adhering to local codes) - and that this saved his house.
I can't vet for the veracity of this claim, but it illustrates that fire-proofness doesn't come naturally.

 

[MikeC]

The steel is certainly not structural - it is holding the windows only.

 

[SR1419]

Obviously this is WAY below the melting point of steel, showing that steel just has to SOFTEN, not "melt."

I have always pointed to the over-pass collapse in Oakland, Ca in 2007 as an example of fire softening steel causing collapse. Interesting in this article the Prof Astaneh claims he saw "melted" steel in the WTC rubble:

Here, it most likely reached about 1,000 to 1,500 degrees. And that is enough to collapse them, so they collapsed. So the word "melting" should not be used for girders, because there was no melting of girders. I saw melting of girders in World Trade Center.

http://www.pbs.org/newshour/bb/science-jan-june07-overpass_05-10/

 

[benthamitemetric]

Many of my colleagues had their commutes into the city delayed today as a result of an intense fire under a train trestle damaging the trestle's steel components: http://www.nbcnewyork.com/news/loca...trands-Thousands-Grand-Central-379914811.html

 

[econ41]

Weakening of steel subjected to heat is well understood and accepted. Design of steel framed buildings is PREMISED on the fire protection plan. The overall picture straight forward "Steel is cheaper and strong BUT you have to design for adequate fire protection". And the fire protection design has to be risk management determined by defining probable scenarios. Instant multi floor initiation of concentrated heaped burnable material triggered by aircraft impact as per WTC "Twin Towers" was not the allowed for "probable scenario". End of argument.

Hence heat weakening is only questioned in the artificial setting of conspiracy theories such as 9/11 CT - where the CTers demand reversed burden of DISproof AND can make any false claim they like. (And "we" go along with it for the ride )

 

[Cairenn]

I need to go grab a picture of a burned church, I spotted today. One of the steel beams is sagging like a overfilled clothesline.

 

[econ41]

I need to go grab a picture of a burned church, I spotted today. One of the steel beams is sagging like a overfilled clothesline.

You may be interested in the story of the original Coventry Cathedral. Some hundreds of years old with timber roof framing. Reinforced with steel in the Victorian era then hit by incendiaries during WW2 bombing raids. The heated steel sagged and brought down the timber frames. The ruins still maintained for memorial reasons. One version which I have not checked for engineering validity suggests that the timber frames may even have survived if they had not been reinforced with steel. Heated steel adding lots of dead weight and zero contribution to strength. It was of somewhat iconic significance and a new Cathedral was built after the end of WW2 - which is now a centre for reconciliation England or UK <>Germany and also with Japan. Dedicated chapels inside the main body of the new cathedral.

It is the first example I think of whenever I come across the truther ignorant nonsense pretending that heat weakening is "unknown".

 

[Mick West]

Here's an interesting presentation that says structurally non-combustible building with unprotected steel are the type of buildings most at risk of collapse.

 

[Jeffrey Orling]

I subscribe to the expanded heated steel pushing columns out of axial alignment in the cores of the twin towers. The beams were 1/4 the length and so the push was likely a few inches... more than enough to destroy the column to column bearing/alignment and destroy the axial load path... leading to local collapse.

 

[benthamitemetric]

Not sure if this has been linked to elsewhere in these forums, but Jose Torrero, a preeminent fire safety engineer and one of the experts who authored a report re WTC 7's collapse for the Aegis Insurance litigation, has a great hour-long talk about how, in his opinion, the ambitious, cutting edge designs of modern sky scrapers simply fail to adequately factor in the risk of collapse from fire:

 

[econ41]

... simply fail to adequately factor in the risk of collapse from fire: ...

Could be interesting - but - sight unseen I'll bet he takes a more conservative view on "adequately". Recall Quintiere's disagreement with NIST which was one of degree NOT principle. (And - yes I know that my implied reasoning is almost certainly circular.) There are - probably - two distinct benchmark issues relevant to WTC collapses - not necessarily the NZ example of this thread viz:
1) Were WTC Towers appropriately designed by the extant standards of their era;AND
2) Do the standards of that era meet contemporary requirements.

The same two apply to this recent NZ example of course. But even that is "off topic" to the theme of "the vulnerability of steel to fire damage is well known".

 

[benthamitemetric]

Could be interesting - but - sight unseen I'll bet he takes a more conservative view on "adequately". Recall Quintiere's disagreement with NIST which was one of degree NOT principle. (And - yes I know that my implied reasoning is almost certainly circular.) There are - probably - two distinct benchmark issues relevant to WTC collapses - not necessarily the NZ example of this thread viz:
1) Were WTC Towers appropriately designed by the extant standards of their era;AND
2) Do the standards of that era meet contemporary requirements.

The same two apply to this recent NZ example of course. But even that is "off topic" to the theme of "the vulnerability of steel to fire damage is well known".

I think you will be surprised how far Torrero goes in outlining what he sees as the inadequacies of the current approach to fire engineering, especially in novel building designs such as that of the twin towers. Does he think engineers are failing from a Hand theory perspective? Unclear. But he certainly thinks they are failing in important ways and that the collapses of the twin towers and wtc 7 all illustrate such failings.

 

[Jeffrey Orling]

Torerro's presentation is spot on. My take away... is that... these were not normal buildings and treated as common buildings and what did them in was inadequate fire protection... an after thought. Essentially he is targeting the designers and the design process. The problem was embedded in the design of the structure... something I have been writing/sailing for 7 years! Thank you Prof. Torerror.

 

[Jeffrey Orling]

Could be interesting - but - sight unseen I'll bet he takes a more conservative view on "adequately". Recall Quintiere's disagreement with NIST which was one of degree NOT principle. (And - yes I know that my implied reasoning is almost certainly circular.) There are - probably - two distinct benchmark issues relevant to WTC collapses - not necessarily the NZ example of this thread viz:
1) Were WTC Towers appropriately designed by the extant standards of their era;AND
2) Do the standards of that era meet contemporary requirements.

The same two apply to this recent NZ example of course. But even that is "off topic" to the theme of "the vulnerability of steel to fire damage is well known".

The point Torerro makes is that fire protection "design" then and perhaps now is not part of the entire design process... but isolated and not integrated. Further the structural design ignores the nature of contiguous multiple floor fires which make the collapse much more likely and of course the very weak structure of the floors which were constrained by much more rigid structures and failed (broke) after pushing and pulling at the columns. He makes the assertion that the fires were no especially hot and that with respect to the design, cooler fires would have the potential to initiate failure.

Fire protection in the twin towers was an after thought... not part of an integrated strategy. Unfortunately the recommendations have focused on egress... inadequate as it was... the real problem was the structure did not and last long enough for people to get out which he asserts is 1 minute per floor.

Inadequate understanding of fire performance in those designs
Inadequate investigation as to why the building performed as they did
Inadequate recommendations and lessons (not) learned

 

[Jeffrey Orling]

I think you will be surprised how far Torrero goes in outlining what he sees as the inadequacies of the current approach to fire engineering, especially in novel building designs such as that of the twin towers. Does he think engineers are failing from a Hand theory perspective? Unclear. But he certainly thinks they are failing in important ways and that the collapses of the twin towers and wtc 7 all illustrate such failings.

He makes the point that all tall buildings are unique and not garden variety structures when it comes to fire protection. He's correct. Apparently designers get away with the 1, 2 and 3 hr fire rating of materials and fail to understand how these materials are integrated and perform together.

 

[econ41]

I think you will be surprised how far Torrero goes in outlining what he sees as the inadequacies of the current approach to fire engineering, especially in novel building designs such as that of the twin towers.

I doubt I would be surprised - and I still have not watched the presentation.

Don't miss the second point I asserted:

2) Do the standards of that era meet contemporary requirements.

The development of standards is a dynamic process. What was once accepted as "best practice" is so often on later review shown to be less than perfect or even negative. Take use of asbestos as one example. I wont spell out the changes of understanding for that one.

In my own field I lived through a revolution in policies related to safety of large dams. The largest of the group of dams I managed was state of the art for its era - 1950's. BUT changes in understanding of dam failure risks shifted world wide standards. It no longer complied. (It was designed for the "one in 1000 year flood" - current standards for dams above concentrated population centres require design for probable maximum flood.) "We" came to know better. No basis for blame of our predecessors. (Except as a middle to fairly high level engineer manager whose bosses designed the dam I had to explain the risks to the political overlords. How my "bosses" in their earlier years got it wrong - by today's standards.....not a pleasant situation to be in...)

Does he think engineers are failing from a Hand theory perspective? Unclear. But he certainly thinks they are failing in important ways and that the collapses of the twin towers and wtc 7 all illustrate such failings.

In no way am I an uncritical apologist for the engineering profession. BUT - accepting that the standards were not good enough THEN one profession blaming another merely irritates me with the inherent dishonesty.

Why blame the engineers for fire dynamics issues - surely the engineers design structures to meet the standards established by the relevant professionals. They don't set the standards - they work within them.

The major failures for the "Twins" were in occupant escape paths,. The (engineered) structures stood long enough for the occupants to escape if the (architect specified) escape routes had been more redundant - alternate paths provided.

And I'm not blaming either fire specialists or architects. ALL the participating professions need to advance understanding as we gain experience. It is my fundamental difference of opinion with Jeffrey Orling. I do not accept the thrust to apply retrospective accountability to persons who followed the accepted standards of the day. Sure - we can learn and progress but there is not blame IMO when hindsight show us that decisions made within the standards of relevant knowledge at the time appear in hindsight to have been wrong or inadequate.

I could re-frame that argument in the language of torts/negligence but I'll take it that you could do that and probably better than me.

 

[Jeffrey Orling]

I doubt I would be surprised - and I still have not watched the presentation.

Don't miss the second point I asserted:

The development of standards is a dynamic process. What was once accepted as "best practice" is so often on later review shown to be less than perfect or even negative. Take use of asbestos as one example. I wont spell out the changes of understanding for that one.

In my own field I lived through a revolution in policies related to safety of large dams. The largest of the group of dams I managed was state of the art for its era - 1950's. BUT changes in understanding of dam failure risks shifted world wide standards. It no longer complied. (It was designed for the "one in 1000 year flood" - current standards for dams above concentrated population centres require design for probable maximum flood.) "We" came to know better. No basis for blame of our predecessors. (Except as a middle to fairly high level engineer manager whose bosses designed the dam I had to explain the risks to the political overlords. How my "bosses" in their earlier years got it wrong - by today's standards.....not a pleasant situation to be in...)

In no way am I an uncritical apologist for the engineering profession. BUT - accepting that the standards were not good enough THEN one profession blaming another merely irritates me with the inherent dishonesty.

Why blame the engineers for fire dynamics issues - surely the engineers design structures to meet the standards established by the relevant professionals. They don't set the standards - they work within them.

The major failures for the "Twins" were in occupant escape paths,. The (engineered) structures stood long enough for the occupants to escape if the (architect specified) escape routes had been more redundant - alternate paths provided.

And I'm not blaming either fire specialists or architects. ALL the participating professions need to advance understanding as we gain experience. It is my fundamental difference of opinion with Jeffrey Orling. I do not accept the thrust to apply retrospective accountability to persons who followed the accepted standards of the day. Sure - we can learn and progress but there is not blame IMO when hindsight show us that decisions made within the standards of relevant knowledge at the time appear in hindsight to have been wrong or inadequate.

I could re-frame that argument in the language of torts/negligence but I'll take it that you could do that and probably better than me.

Ozzie I think your point that standards and best practice are evolving is correct. However... the point he makes (I think) is that the approach to fire safety issues was "lax" and that structural engineers and architects didn't take this "seriously" in the sense that they could even back then have designed the structures to be more survivable... for the occupants. This INCLUDES the amount of time a structure needs to stand in order for the occupants to escape... taller buildings need to stand longer.

He also makes the point that fires on contiguous floors are much more prone to failure and at lower temperatures. Add to that the very long spans and very thin floors and it explains why the towers went as quickly as they did... according to him obviously. He asserts that the fires need not be out of the ordinary... especially hot either.

I don't think the thrust is to make engineers accountable retrospectively in a "legal sense". I think what he is saying is that tall buildings should be recognized as different creatures and need different solutions are far as safety (fire). This was not something that should not have been ignored. In fact he goes on to note how many buildings over 100 stories have been built since 2000 continuing to ignore this special fire, egress and collapse risk nature of tall buildings.

Even today the approach seems to simply apply rated fire proofing to elements and ignore the way fire works, spread and impacts various structural features. His thinking about think floors seems to suggest that he believes that the "ROOSD" process was what destroyed the twin towers... the missing columns and so forth of the collapsing tops were an artifact or a consequence of what the OOS floors were doing. I am not sure if I am on board with his outside the core floor collapse driven "cause"... as opposed to a core led initiation. It would seem that a requirement for the outside the core driven collapse would be for the contiguous fires to be over a very wide area of the foot print... and it's similar to the pancake concept conceptually (no pancakes but fire caused floor wide collapse/destruction.

He seems to think that the fire performance of the floor system was not and should have been modeled or studied and not just assume that some spray on fire retardant would do the trick. And this seems to be how architects and builders approach this issue even today.

 

[Jeffrey Orling]

The major failures for the "Twins" were in occupant escape paths,. The (engineered) structures stood long enough for the occupants to escape if the (architect specified) escape routes had been more redundant - alternate paths provided.

Ozzie this is NOT true... egress in requires 1 minute per story height minimum. That would mean that the twins should have stood 110 minutes minimum for occupants to get out.. almost 2hrs. The consider how narrow the egress stairs were and this need to stand time would increase.

YES for 7wtc the building exceed the 1 min per floor standard. Not so for the twin towers.

 

[econ41]

Ozzie this is NOT true... egress in requires 1 minute per story height minimum.

Take care that you don't miss the point I made. AFAIK nearly all the occupants below the fire/impact zone escaped. So they had time. Whether they were faster than code and whether the building met ONE of the code specifications is not the point I made. Particularly as a "single aspect out of context" criticism.

Those above the fire/impact zone would not have escaped if the building had stood for 3 hours. And time for a lot of people to escape is a function of BOTH "how many - how wide the paths?" AND "how long do we have?" (And a few more - age - agility - fitness for the required exercise....lighting of the pathways....)

That would mean that the twins should have stood 110 minutes minimum for occupants to get out.. almost 2hrs.

Even that is questionable - the code would mean "...110 minutes minimum for occupants to get out.. almost 2hrs" for the fire dynamics assumed in the design parameters - NOT the gross over trauma which was 9/11.

The consider how narrow the egress stairs were and this need to stand time would increase.

...as I said "...escape routes had been more redundant - alternate paths provided."

YES for 7wtc the building exceed the 1 min per floor standard. Not so for the twin towers.

I'll take a rain check on that - it is true but......

 

[econ41]

Ozzie I think your point that standards and best practice are evolving is correct.

Which was the main point of my comment - deliberately posted BEFORE I watched the clip.

His thinking about think floors seems to suggest that he believes that the "ROOSD" process was what destroyed the twin towers... the missing columns and so forth of the collapsing tops were an artefact or a consequence of what the OOS floors were doing. I am not sure if I am on board with his outside the core floor collapse driven "cause"... as opposed to a core led initiation.

I'm aware that you are in the minority - those who support some variants on T Szamboti's core led claims. I dont. I both accept the mainstream understanding and have explained it in detail many times. (Or to be even more pedantic I have published my own explanations of what really happened - AND the "accepted narratives" to a large extent align with my understanding. You are/should be familiar with my reasons for that position.)

It would seem that a requirement for the outside the core driven collapse would be for the contiguous fires to be over a very wide area of the foot print... and it's similar to the pancake concept conceptually (no pancakes but fire caused floor wide collapse/destruction.

Sorry I cannot go along with the confusion of "initiation' and "progression" stages. You are familiar with my posted detailed explanations - feel free to rebut them in the appropriate threads and forums if not this one.

He seems to think that the fire performance of the floor system was not and should have been modeled or studied and not just assume that some spray on fire retardant would do the trick.

He is advocating "evolutionary progress" of professional practice and Code requirements. I agree.

And this seems to be how architects and builders approach this issue even today.

"even today" tho not "back then" - the same evolutionary process.

 

[Jeffrey Orling]

He is advocating "evolutionary progress" of professional practice and Code requirements. I agree.
"even today" tho not "back then" - the same evolutionary process.

I suppose as a fire science/engineer one of his main points was that prescriptive fire engineering was taken seriously enough as part of the design with respect to "life safety". It was more of an after thought by simply applying fire protection when and if possible and convenient but not considering how the engineering itself would perform in various fire scenarios... such as thin slabs with fires on contiguous floor. One may argue that such fires are unlikely. But he also argues that curtain wall construction allows for air and fire to quite easily move between floors...leading to multiple floor fires at the same time. This is very different in terms the the floors surviving from a single floor fire.

So I think he implies that the engineers and architects dropped the ball...

Maybe

 

[econ41]

OK - I've now watched the 1 hour video to the 30 minute mark.

And I am not satisfied that he is on target for a legitimate balanced approach to the topic. I'm also convinced that discussions on this and other forums between some of our regular members have taken a more realistic and more sophisticated look at the issues. And in better balance than the Prof shows in the first half of his presentation.

One central issue will suffice:

He has - so far - shown that he regards WTC 9/11 collapses and subsequent investigations as erroneous or inadequate as a result of a range of "para-political" pressures - broadly falling under the drive of the need to go forward.

BUT by implication he is asserting that the designs should have and future designs should withstand anything that happens.

I reject that assessment.

IMNSHO it is valid professional reality both for generic code provisions and for design of any specific building that design standards MUST be risk managed for prudently determined "reasonable risks" and NOT for the worst case imaginable. Which means designing prudently for any "reasonably foreseeable" possibility AND the probability associated with it.

Put simple it is NOT viable to design for improbable worst case scenarios.

The challenge IMO is putting the line in the right place in the grey area.

I can explore those aspects in more detail but that should suffice as an outline of my disagreement with the Professor's strongly implied goal.

And I'll watch the rest of the video. I'm tempted to do a professional level critique BUT.....it would necessarily be lengthy. However I may see if I can condense a "key points" summary. The single point identified above should suffice to determine if there is any interest in discussing the topic further.

Try this version: "Do any members think that buildings should be required to be designed for worst possible case?"

 

[Jeffrey Orling]

OK - I've now watched the 1 hour video to the 30 minute mark.

...

Try this version: "Do any members think that buildings should be required to be designed for worst possible case?"

I did not get this as the thrust of his talk. He certainly is not advocating that tall buildings be designed such that they don't collapse in a "worst case".... whatever that is.... scenario.

Fire protection is based on 2 things...

passive protection... spray type or enclosure of steel inside of rated materials...

or

active protection.. such as wet or dry sprinklers and I suppose fire fighting by the fire department.

In tall buildings fire fighting is virtually a non starter if the fire is on a high floor or floors.

Active protection works as long as there is water and water pressure... and in the case of the WTC event that was lost pretty quick.

It's debatable how much the spray on stuff stayed on and worked. Clearly it would not survive the collapse so not seeing on the steel is no measure of what the planes may or may not have done to it.

My sense is that fire safety design is almost an after thought.. then and maybe up until recently. The new Freedom Tower has a much more robust fire protection safety / egress design... than what we were seeing before... That's for sure.

Planes hitting tall buildings is way too outlier to design for.

 

[econ41]

I did not get this as the thrust of his talk. He certainly is not advocating that tall buildings be designed such that they don't collapse in a "worst case".... whatever that is.... scenario.

He made no distinction that I could recognise between "fires within a reasonable design envelope" AND the "Way beyond reasonable design parameters that WTC1 & 2 presented". NOT making that distinction is a major shortcoming IMO. Where does he say:
A) "WTC design should NOT have allowed for deliberate sabotage by aircraft impact." OR
B) "WTC design SHOULD have allowed for the possibility?

(OR is he leaving the issue open as a mental challenge for his audience - I don't get that impression.)

Fire protection is based on 2 things...

passive protection... spray type or enclosure of steel inside of rated materials...

or

active protection.. such as wet or dry sprinklers and I suppose fire fighting by the fire department.

In tall buildings fire fighting is virtually a non starter if the fire is on a high floor or floors.

Active protection works as long as there is water and water pressure... and in the case of the WTC event that was lost pretty quick.

It's debatable how much the spray on stuff stayed on and worked. Clearly it would not survive the collapse so not seeing on the steel is no measure of what the planes may or may not have done to it.

err .....sort of ...yes??? I don't see the relevance of partial explanations of what should be agreed ground.

My sense is that fire safety design is almost an after thought.. then and maybe up until recently. The new Freedom Tower has a much more robust fire protection safety / egress design... than what we were seeing before... That's for sure.

Why at this stage of this discussion are you still treating the need for ongoing improvement as if it was doubted? I certainly accept that aspect of the Professor's presentation as given fact. I'm questioning the ruddy great gap in his scope of topic - not the bits he undoubtedly in my mind gets right.

Planes hitting tall buildings is way too outlier to design for.

That is what I have said in both specific and generic terms. And I don't see the Professor recognising or addressing the issue of "how far should we go?"

 

[Jeffrey Orling]

I don't think he cares about planes hitting buildings... I think he cares about uncontrolled fires... 7wtc was not hit by a plane.... Do you think the falling debris was the thing which got it going? Other buildings had debris damage...

 

[Mick West]

I-85 fire and collapse discussion moved to:
https://www.metabunk.org/i-85-freeway-fire-and-collapse-world-trade-center-comparisons.t8550/

 

[Admiral Biscuit]

I think this is the right thread for this . . .

Recently, a local abandoned factory burned down. Fire departments fought the fire from about noon to 3pm (source: MLive)

Anyway, here's some pics:

Before the fire (source: google maps)--I included the address in case anyone wants to look it up.

The fire was fought, it doesn't seem like there was much load above the third floor--satellite view just shows a roof with no significant equipment on it. And yet there was a lot of buckled/bent steel in the structure, as well as a collapse.

 

[Jeffrey Orling]

Steel lost strength from being heated to BELOW the safe working load and buckled.

 

[Mick West]

The fires in Maui left some stark examples. There are several destroyed commercial building, but this area around 900 Front St (Intersection with Papalaua St) is one of the best documented

View attachment 62245

 

[psikeyhackr]

Like the issue is just fire and steel.

Doesn't thickness (quantity) of steel and the amount of time have something to do with it?

What is the difference between structural steel that must support 15 stories versus what only has to support 4. Oh, it was more like 35 stories for the South Tower and it came down in less than an hour.

Of course there was jet fuel, sometimes known as kerosene. But they say that was mostly used up in minutes and a lot exploded outside of the South Tower without having much visible effect on the columns.

Funny how we can't just get the amount of steel and concrete on each of 116 levels in 22 years.

 

[Oystein]

Like the issue is just fire and steel.

Doesn't thickness (quantity) of steel and the amount of time have something to do with it?

Sure. Something.

What is the difference between structural steel that must support 15 stories versus what only has to support 4. Oh, it was more like 35 stories for the South Tower and it came down in less than an hour.

The difference is not nearly as much as you might think. For starters, the thickness of the critical floor trusses does not vary from floor to floor, does not vary with tower height, as each floor supports only itself. These trusses were suprisingly flimsy.
Then, the thickness of the steel plates that built up the perimeter was under an inch. Steel is a decent conductor of heat. It doesn't take very long for the heat of fires to penetrate the entire thickness of those box columns.
That is the reason why fireproofing material is applied to the surface of steel structures. With fireproofing, steel is supposed to resist critical heating for 2 hours or more, without fireproofing, we are talking about mere minutes.

Of course there was jet fuel, sometimes known as kerosene. But they say that was mostly used up in minutes and a lot exploded outside of the South Tower without having much visible effect on the columns.

*sigh*
Jet fuel? Really?

Let's do a quick couple of back-of-the-envelops:

Each plane dumped something like 10,000 gallons of jet fuel into the towers, of which 1/3 (or 2/3? I forgot) may have burned outside (visible fireball) with very little effect on heating the structure. The rest was distributed over like 5 floors. So that's, order of magnitude, 1,000 gallons of liquid fuel per floor. That's, order of magnitude, 3,000 kg at a specific heat of 40 MJ/kg. That's 120,000 MJ

A typical office workstation has 200 kg of combustibles (desk, computers, papers, carpet, cables, associated plumbing, ...), and each WTC floor had 200 workstations, that's 40,000 kg of combustibles per floor, at a specific heat averaging probably 15 MJ/kg or so. That's 600,000 MJ.

So, to a first approximation, the heat released by burning office contents was 5x the heat released by the jet fuel.
The relevance of the jet fuel is not so much that it is what heated the steel (it contributed, but only a minor percentage of total heat). The relevance is that it served as an accelerant getting huge fires started concurrently on several adjacent floors.

This has been explained to Truthers over and over and over and over again for two decades now. Please indicate in your response that you carefully read the explanation, and whether you now understand it!

Funny how we can't just get the amount of steel and concrete on each of 116 levels in 22 years.

Huh?
We know the amount of the concrete on each floor - for the floor slabs themselves, it was 4 inches of light-weight concrete throughout the office spaces, and 5 inches of regular concret in the core spaces. The stairs had some concrete that provided mass but no structural strength to the superstructure. And that's it. Concrete in the basements and foundations is irrelevant.
As for the steel, we know exactly the dimensions of the floor trusses (they were the same on all floors) and also how thick the steel plates of columns were on each level.

 

[Mendel]

Like the issue is just fire and steel.

Doesn't thickness (quantity) of steel and the amount of time have something to do with it?

What is the difference between structural steel that must support 15 stories versus what only has to support 4. Oh, it was more like 35 stories for the South Tower and it came down in less than an hour.

Of course there was jet fuel, sometimes known as kerosene. But they say that was mostly used up in minutes and a lot exploded outside of the South Tower without having much visible effect on the columns.

Funny how we can't just get the amount of steel and concrete on each of 116 levels in 22 years.

Think of an arsonist. They arrive at a house with a jerrycan of gasoline, splash that around, then set it alight. Why? To create a nice big blaze right from the start that can't be put out easily. The fact that there were huge fires on several floors was a big problem for WTC1 and WTC7.

The knock-on problem was that the sprinkler systems failed; for WTC7, because the WTC1 collapse damaged the water mains.

The thickness of steel is proportional to the load it has to carry, right? If a blacksmith bends a thin steel beam with little force or a thick steel beam with a lot of force, that's going to work either way, right? She just has to put the steel in the forge fire for a while to soften it up.

So, were the WTC "forge fires" hot enough for long enough, and the forces strong enough, to make that happen?

That's what the engineers at NIST were tasked to find out, and that why they collected a lot of data and ran fire simulations, and then put the heat effects in their steel and loads simulations, and found the simulated buildings broke in much the same way that the real buildings did. Download and read the NIST reports, there's a lot of attention to detail, including "the amount of steel and concrete on each of the 116 levels". The report on the towers has been out for almost 18 years now.

 

[Gamolon]

Huh?
We know the amount of the concrete on each floor - for the floor slabs themselves, it was 4 inches of light-weight concrete throughout the office spaces, and 5 inches of regular concret in the core spaces. The stairs had some concrete that provided mass but no structural strength to the superstructure. And that's it. Concrete in the basements and foundations is irrelevant.
As for the steel, we know exactly the dimensions of the floor trusses (they were the same on all floors) and also how thick the steel plates of columns were on each level.

Oy,

Unfortunately (and you probably know this already), psikeyhackr is not interested in the fact that the amount of steel and concrete is out there. I've told him this same information many times before in other forums. I've even pointed him to material lists for the columns which show plate thicknesses and other pertinent information. I've pointed him to blueprints for each floor.

It goes in one ear and out the other and he just continues make the same statements and ask the same questions about the amount of steel and concrete.

 

[Gamolon]

Funny how we can't just get the amount of steel and concrete on each of 116 levels in 22 years.

You've been given this information numerous times in the past. For a specific example, back in June of this year at the US Message Board, you asked:

The 100 tallest buildings on the planet are over 333 meters tall. The Twin Towers were 415 meters.

How much steel was on level 5 compared to level 105? Why is the Eiffel Tower shaped the way it is? It does not have to support double its own weight in concrete.

Physics has been History since 9/11. Self righteous dummies can believe stupid shit without asking obvious questions. All of these skyscrapers all over the world! Where is the data on the steel and concrete distributions?

I provided two screenshots of blueprints for the core for both the 5th and 105th floors showing box columns on the 5th floor and I-Beams on the 105th floor. I then provided the Core Column Schedule drawing for core column 906B, which showed the type of column used between each 3 floor section from top to bottom. Below is a screenshot of some of that information complete with beam type and steel plate thickness for the box columns:

Why are you still asking these particular questions when the answers have been provided to you many times in the past?

 

[Dan Burt]

You've been given this information numerous times in the past. For a specific example, back in June of this year at the US Message Board, you asked:



I provided two screenshots of blueprints for the core for both the 5th and 105th floors showing box columns on the 5th floor and I-Beams on the 105th floor. I then provided the Core Column Schedule drawing for core column 906B, which showed the type of column used between each 3 floor section from top to bottom. Below is a screenshot of some of that information complete with beam type and steel plate thickness for the box columns:


Why are you still asking these particular questions when the answers have been provided to you many times in the past?

I've hesitated since joining the forum responding in threads (with the exception of the "Debunking humor" thread). As I don't have the knowledge required to bring anything to the table debate wise the topics discussed here. I enjoy the forum to learn from others experience and ability to explain complex things simply. And for that I am greatly appreciative. However, I do have much experience in sarcasm and "trolling" online. I also feel I have a good amount of common sense. And my sarcasm experience and common sense tells me the person you are responding to is "trolling" you. Or they could just not be very smart and or honest with themself and ignore that which doesn't go along with their pre-determined outcome of events. Either way you are obviously (to me) wasting your time repeating yourself to this person on multiple forums. I respect your patience doing this but just wanted to point out there are people that will spend many hours wasting your time just so they can tell their friends they wasted your time.