Total Building Collapse from a Single Column Failure

[Robrob]

I would guess that the Empire State Building if hit as the twins were would not have collapsed totally if at all and surely not in the brief period of time that the twin towers did. I had an office on the 74th floor of the ESB and it was built like a battleship... very much unlike the erector set construction of the Twin Towers.

You are correct. Completely different construction.

 

[Gamolon]

I believe there were multiple factors which facilitated the collapse of each tower... and that a KEY factor was the actual engineering design. I am suggesting that the uniqueness of these designs was a larger factor that NIST or anyone for that matter seems to consider.

You have these factors to consider:

uncontrolled fires
atypical accelerants (such as stored diesel)
loss of fire protection on steel
inoperative sprinkler system
electrical equipment exploding
mechanical damage - plane and or falling debris
age of structure and connections
engineering features such as framing design, FOS, design and service loads
siting 7 wtc over con ed sub station
fabrication issues

All of the above were contributory factors. None of these factors appears to be sufficient on its own. It was a joint effort of factors.

The above coupled with this:

Roberston knew his design folded like a cheap table. He's dodging everyone on that and you can see it in his face. He feels very guilty... as well he should.

Can you explain, from a structural engineering standpoint, which permutation of the above "factors" Robinson (or any other structural engineer) should have considered?

 

[jaydeehess]

With all due respect... that's a but of a dodge for the engineering aspects of these three towers.

As a general comment... these three designs have many very unusual engineering attributes to them. Why have not these come under some scrutiny? Why precipitate the recommendations to "improvements in codes"?

What sort of improvements? extend the hrs of fire protection rating?

Column 79 could be the location of the initiation as the EPH collapse was the first obvious movement that the tower was coming down. Structure under it had failed... We don't know how far down the failure... Could have been anywhere from the ground up to about flr 20 which is the visible portion of the facade where the EPH collapse can be observed.

I've asked for explanation how girder walk off fails the column. No one has explained that to me. When someone provides the explanation girder walk off will be on the table as a possible cause for the initiation.

It's true that there is no evidence to support first around the transfer truss region. But there are no reports either that these structures were fine.

My understanding is that Hess was trapped by the East stair and if so the explosion he witnessed was in the transfer truss region. What else it did besides blow up the stair is another matter. I don't buy the notion that falling WTC debris crashed into the East stair at flr 6 or so. That makes no sense at all. More plausible is that electrical power equipment exploded. And there was plenty of that down there.

I've suggested that the massive truss failure could gave occurred at the splices which were 3/4" bolts and plates... both more susceptible to heat damage than 5" thick plate of the trusses themselves. Ergo it would not take the raging fires for extended periods to fail the connection and a truss. Perhaps.

If you don't want to explore TTF then support girder walk off... not that it happened... but how does that progress to a building collapse.

Take your pick.

IIRC its was Jennings that said there was an explosion while Hess says there was a lot of smoke and dust but not an explosion.(and lights went out)

 

[beachnut]

... I would guess that the Empire State Building if hit as the twins were would not have collapsed totally if at all and surely not in the brief period of time that the twin towers did. I had an office on the 74th floor of the ESB and it was built like a battleship... very much unlike the erector set construction of the Twin Towers.

...

That is a guess.

The ESB suffered a lot of damage from an impact equal to 41 pounds of TNT by a B-25, it put a hole in the wall. The WTC impacts were 1300 and 2093 pounds of TNT. An impact from a B-25 would have been stopped by the WTC. Someone forgot to do the math.

http://www.baruch.cuny.edu/nycdata/disasters/aircrafts-empire_state_bldg.html

It would all rest on the insulation used in the ESB. The WTC towers were stronger than the ESB, else they would not have been taller. The weak spot was the insulation being easy to remove.

Oh, battleships are made of limestone, granite, and 10 million bricks?

 

[leftysergeant]

IIRC its was Jennings that said there was an explosion while Hess says there was a lot of smoke and dust but not an explosion.(and lights went out)

More importantly, Jennings stated that it sounded nothing at all like a boiler or a transformer blowing up. He had heard those.

They sound like bombs, usually.

Two of the world's tallest buildings falling into the street is a sound you have never heard before in your life.

 

[Robrob]

More importantly, Jennings stated that it sounded nothing at all like a boiler or a transformer blowing up. He had heard those.

They sound like bombs, usually.

Two of the world's tallest buildings falling into the street is a sound you have never heard before in your life.

It's strange, the Truther's obsession with what adjective a lay-person used to describe the loudest sound they ever heard in their life.

 

[Animal]

That is a guess.

The ESB suffered a lot of damage from an impact equal to 41 pounds of TNT by a B-25, it put a hole in the wall. The WTC impacts were 1300 and 2093 pounds of TNT. An impact from a B-25 would have been stopped by the WTC. Someone forgot to do the math.

http://www.baruch.cuny.edu/nycdata/disasters/aircrafts-empire_state_bldg.html

It would all rest on the insulation used in the ESB. The WTC towers were stronger than the ESB, else they would not have been taller. The weak spot was the insulation being easy to remove.

Oh, battleships are made of limestone, granite, and 10 million bricks?

One note......Depends on what you mean by "stronger" Yes the WTC structure carried more load, but the ESB has a far greater reserve strength since they were in the infancy of high rise design when it was built.

 

[Gamolon]

Wrong.

It's only nonsense to those who may not have the sense to see the relevance. I cited examples of industrial engineering failures... Do you deny these happened?

I am not seeking to turn anything done in the past into a unlawful act after the fact. I never mentioned any violation or criminal or civil code. I don't think there was intent to do harm. Incompetence and misconduct may not involve intent. In fact the engineers who screw up, always think they are doing a stellar job!

I don't even want to get into the legal arena. I am seeking the proper explanation for the collapses which I don't think NIST got right and assign the appropriate share of the cause to the engineering, planning and approval decisions. Some here claim these designs performed better than could expected. I find that a stretch.

Based on your failed engineering examples presented previously and they way you are speaking about accountability and that Robertson SHOULD feel guilty, I am assuming you think that Robertson and his firm did analysis of WTC1 and WTC2 in regards to a 767 smashing into them AND the resultant fires, found out that they would totally collapse, and then never presented that data?

All for money/greed?

 

[jaydeehess]

It's strange, the Truther's obsession with what adjective a lay-person used to describe the loudest sound they ever heard in their life.

At one time I would assist the cable techs when they were doing line replacements. This involves placing a 40 pound machine on the strand wire between poles, and pulling it along the strand. It wraps the cable onto the strand with a thin wire. All this to keep the cable tight to the heavy strand. In most cases this machine is taken up in a bucket and placed on the wire. However in some backyard pole lines you cannot get the truck in there and the tech has to climb the pole and pull the machine up with a rope, and at the other pole one climbs then lowers the machine with a rope, or takes from one side of the pole to the other side and onto the strand wire again.
Once the tech was transferring it from one strand to the one on the other side of the pole and he dropped it. It fell 24 feet to the backyard lawn.
It made a WHOOMP when it hit. I felt the impact through my boots and I was standing 20 feet away. Had I not been watching I would have suspected something exploded.
That was 40 pounds. 400lb, 4000lb, 40000lb, or 400000lb probably are a lot louder, dropping onto something other than a grassy lawn, probably a lot louder

**JSO is not a truther**

 

[jaydeehess]

t some point you need to look at the benefit of naming the person to blame for failures in the past as opposed to changes that benefit for the future. This seems obvious to most.

I'm not sure anyone did anything wrong in the design of the WTC buildings. Some people think there is a need to point fingers.

Need to point only if there is some responsibility or failures. I think there were.

excuse me? There are crimes which have no statute of limitations. it is not morally repugnant to find a murderer and bring him to justice. Why shouldn't any other sort of criminal act or professional incompetence not have the same standard or justice?
Let's not jump the gun here. It hasn't even been established...not even examined as far as I can tell, if the engineering / design and planning decisions were a significant factor in the collapse... not the only one... maybe not the key one.

And even if it could be shown that very wrongheaded decisions driven by economy (read greed) were in play I don't know that this is criminal. You're putting the cart before the horse and declaring there's no there there and why bother.

I've raised the example of the Pinto gas tank. Pintos were fine cars unless rear ended... and then they were deathtraps. Ford argued that bad drivers killed the occupants. The product liability action determined that Ford had some level of culpability and after the fact... many years because law suits can take decades to reach a decision.

Perkin Elmer built the lens for the Hubble Telescope and ground it to the wrong radius. Probably lots of engineers were involved in that one. We paid for it and paid for it to be repaired and people risked their lives too. No one should be held accountable? Should they be paid? Be sued? Return the contract sum? With penalty?

What about the engineers who pulled a boner with the Challenger and 7(?) people died and multiple 10s of millions of tax payers' dollars lost? No accountability? No one gets the pay docked? or loses their job? No engineer's liability insurance pays back the tax payers?

Ozzie, you seem too willing to not hold people accountable who let 9/11 turn out as tragically as it did... and there were lots of them who were well paid and did a lousy job.

Wrong.

It's only nonsense to those who may not have the sense to see the relevance. I cited examples of industrial engineering failures... Do you deny these happened?

I am not seeking to turn anything done in the past into a unlawful act after the fact. I never mentioned any violation or criminal or civil code. I don't think there was intent to do harm. Incompetence and misconduct may not involve intent. In fact the engineers who screw up, always think they are doing a stellar job! I don't even want to get into the legal arena. I am seeking the proper explanation for the collapses which I don't think NIST got right and assign the appropriate share of the cause to the engineering, planning and approval decisions. Some here claim these designs performed better than could expected. I find that a stretch.

Why do some of your posts contradict others?

You do see that what you wrote, that which I underlined, seemingly contradicts the otherwise hilited portions above, right?

 

[Mark F]

I'm wondering if we are forgetting who the real criminals were here. If not for those 19 d-bags and their overlords in A-stan we would not be having this discussion.

 

[jaydeehess]

I'm wondering if we are forgetting who the real criminals were here. If not for those 19 d-bags and their overlords in A-stan we would not be having this discussion.

True, however there is good reason to investigate the results to see if there were contributory factors inherent in design of the buildings that resulted in greater death, injury, and destruction.

In the towers there was the interior fire stair design and the allowance for drywall firestop as fire stairwell walls, Non-cementatious fire insulation, and no diagonal bracing between floors.
It was also determined that trying to design against aircraft impacts was prohibitive financially, even it it were possible to design for.

In #7 the asymettric beam layout, the long span floor design, and the large construction over an existing structure were contributory beyond the effect of impact damage and unfought large area fires.

 

[Mark F]

True, however there is good reason to investigate the results to see if there were contributory factors inherent in design of the buildings that resulted in greater death, injury, and destruction.

In the towers there was the interior fire stair design and the allowance for drywall firestop as fire stairwell walls, Non-cementatious fire insulation, and no diagonal bracing between floors.
It was also determined that trying to design against aircraft impacts was prohibitive financially, even it it were possible to design for.

In #7 the asymettric beam layout, the long span floor design, and the large construction over an existing structure were contributory beyond the effect of impact damage and unfought large area fires.

But by no means criminal.

Design is always an evolutionary process. Cars are safer now than they used to be because we have a century of experience with auto accidents and technological advancements. I'm not going to hold the (now probably dead) designers of my old 1971 MGB criminally liable for not providing front and side airbags, crumple zones and ABS brakes with traction control if I get in a crash. That would be ridiculous.

 

[JSanderO]

But by no means criminal.

Design is always an evolutionary process. Cars are safer now than they used to be because we have a century of experience with auto accidents and technological advancements. I'm not going to hold the (now probably dead) designers of my old 1971 MGB criminally liable for not providing front and side airbags, crumple zones and ABS brakes with traction control if I get in a crash. That would be ridiculous.

I think criminal implies intent to break some law for whatever reason. No one is alleging that there was any criminal intent. I do believe that the design features in this case more easily enabled to total collapse of these buildings. And often engineering design is driven by cost consideration. The twin towers seem to be to be rather inexpensive construction and the low cost per SF and the erection time were lauded at the time and 7WTC was built over a Con Ed sub station for no good reason considering the vacant lot available right across west street where a very conventional framed building could have been built. Building over the sub station seems like a very odd location... all things considered.

The type of construction of the twin towers may have played a part.

Maybe

 

[911KookDetector]

7WTC was built over a Con Ed sub station for no good reason considering the vacant lot available right across west street where a very conventional framed building could have been built. Building over the sub station seems like a very odd location... all things considered.

I believe the original plans for the Con Ed substation included the construction of a high-rise tower above it.
The footprint of 7 WTC was larger than intended, though, which led to the discontinuities between the columns in the substation and those in 7 WTC.

 

[Newtons Bit]

I think criminal implies intent to break some law for whatever reason. No one is alleging that there was any criminal intent. I do believe that the design features in this case more easily enabled to total collapse of these buildings. And often engineering design is driven by cost consideration. The twin towers seem to be to be rather inexpensive construction and the low cost per SF and the erection time were lauded at the time and 7WTC was built over a Con Ed sub station for no good reason considering the vacant lot available right across west street where a very conventional framed building could have been built. Building over the sub station seems like a very odd location... all things considered.

The type of construction of the twin towers may have played a part.

Maybe

Yes, the type of construction at the twin towers did play a part. They were incredibly redundant, much more so than typical construction, and allowed the people inside more time to escape than other typical construction would allow for.

 

[JSanderO]

Yes, the type of construction at the twin towers did play a part. They were incredibly redundant, much more so than typical construction, and allowed the people inside more time to escape than other typical construction would allow for.

Redundant? How so?

 

[ozeco41]

Discussions in this thread are crossing several areas - legal, structural engineering past practice, possible better standards for future engineering and allocation of accountability to name just four.

Lets look at the legal issues first.

These discussions have arisen because Sander has some concerns about possible design weaknesses in the WTC Towers which may have contributed to the scale of the disaster. I accept that Sander has grounds for concern but the challenge is to getting those concerns in focus and determining what remedial action, if any, the US community should take.

So starting with the legal issues Mark F has pointed to a key factor:

I'm wondering if we are forgetting who the real criminals were here. If not for those 19 d-bags and their overlords in A-stan we would not be having this discussion.

I don't think any of us are forgetting Mark but the reminder is appropriate. Certainly Sander has focussed on the accountability of designers. Let's just explore some legal realities.

Legal remedies fall into two classes:

1) criminal law where the guilty party has contravened a requirement of the community expressed as a statute law. Murder is one crime and that is why I took strong objection to Sander using it as a (false) analogy to the WTC design situation. Murder requires INTENT and it is ridiculous to suggest that those who designed the WTC Towers intended to kill occupants either by the building trapping them in a fire or by collapsing. So forget crime and criminal remedies.

2) civil law where one party is alleged to have "injured" another party. Where "injured" has a broad meaning - actual bodily injury, loss of property or loss of money. even loss of opportunity. Successful civil actions usually result in the award of "damages" - a monetary sum to compensate for the "injury" caused" - whether or not the original injury was bodily injury.

So that is the "Legal Basics 101" setting.

Now "Torts 102" is the area relevant to where Mark's quoted statement intersects with Sanders concerns.

IF << note the "big "IF" - IF there was any action against the original designers it is conceivable that it would be for negligence. Sander has several times referred to "product defect liability" and it is a broadly analogous situation. (And it happens to be one where the evolution of US law has led the "common law" world over recent decades.)

At most, in a cilil action, the negligence alleged by the designers would only have the status of "contributory negligence". I wont pursue the details further because1) it gets too complicated; AND 2) I've forgotten most of it

BUT remember the very big "IF" at the start of this section.

Given the scale of the maliciously caused disaster I do not see any Western style government allowing such an action. Even if existing statute law, case law and precedents permitted it I would anticipate immediate blocking action by Government. The reasons go to the foundation premises of risk and insurance policy and law. They are too far off track for here.

So bottom line - whatever value Sander sees in 'accountability' with or without sanctions - there is no chance of criminal reparations and the possibilities for civil action are very limited - probably non existent.

The remedied for what may have been weak in WTC design lie in the evolution of design. Not individual or corporate sanctions applies retrospectively. I'll leave that for a technical post.

 

[Justin39640]

I think criminal implies intent to break some law for whatever reason. No one is alleging that there was any criminal intent. I do believe that the design features in this case more easily enabled to total collapse of these buildings. And often engineering design is driven by cost consideration. The twin towers seem to be to be rather inexpensive construction and the low cost per SF and the erection time were lauded at the time and 7WTC was built over a Con Ed sub station for no good reason considering the vacant lot available right across west street where a very conventional framed building could have been built. Building over the sub station seems like a very odd location... all things considered.

The type of construction of the twin towers may have played a part.

Maybe

It's Wall Street! Real estate is kind of a premium down there...

The good reason was probably because all of the existing infrastructure already going to and from that location. Not to mention what else is under the street in that area (subway lines, etc).

That's not a vacant lot, it's a park.

Redundant? How so?

They got hit by a plane. The fact they didn't collapse immediately was a miracle.

 

[JSanderO]

It's Wall Street! Real estate is kind of a premium down there...

The good reason was probably because all of the existing infrastructure already going to and from that location. Not to mention what else is under the street in that area (subway lines, etc).

That's not a vacant lot, it's a park.



They got hit by a plane. The fact they didn't collapse immediately was a miracle.

The lot I refer to was from the land fill from the bathtub. The WFC and Battery Park City were built on it. The lots to the north of WFC diagonally across the intersection of Vesey Street was vacant and was vacant on 9/11/2001. it was used for a parking lot.

Why the developers chose to build a complicated structure over Con Ed is something that needs to be explained. It certainly made from a very complex frame w/ huge transfer trusses and all manner of odd ball framing. WHY? It seems as a no brainer to the developer to purchase the vacant lot and build a simple frame. WHY didn't he?

Collapse immediately? How would that be? You don't think the building could be knocked over by a plane do you?

The towers collapse because of what happened AFTER the planes hit. Do you understand that?