So who the heck ever said "Pull it" was slang for controlled demolitions?

Continued:

Deflection = P*a *(3L^2 – 4*a^2)/(24*E*I) (Formula from AISC LRFD 3rd)
a = 1/3*L
= P * 1/3L *(3L^2 – 4/9*L^2)/(24*E*I)
= 23*P*L^3/(1296*E*I)
= 23*6k*(37ft*12in/ft)^3/(1296*29000ksi*739in)
= 0.435in

Additional moment due to P-delta
Mu+ = 0.435in*139k = 61.02 kip*in


Additional Deflection = Mu+*L^2 / (4*EI)
= 61.02kip*in*(37 * 12ft\in)^2 / (4*29000ksi*739in^3)
= 0.140in

Additional moment due to P-delta2
Mu++ = (0.435+0.140)in*139k = 79.93 kip*in


Additional Deflection = Mu++*L^2 / (4*EI)
= 79.93kip*in*(37 * 12ft\in)^2 / (4*29000ksi*739in^3)
= 0.184in

As seen, the first p-delta iteration results in an increased deflection of 0.140in. The second results in a deflection of only 0.184in. We can thus conclude that p-delta will eventually converge and that no further iterations are necessary. The 6kip pull-in force with no effect of fire will not result in the column becoming unstable.


In a 600C fire, the Modulus of Elasticity will have reduced to approximately 0.3 of its original value, and the yield strength to 0.5 of its original value. The effect of the Modulus of Elasticity being so greatly lowered is of far greater important than the yield strength, however.

CALCULATION 2: DIAPHRAGM DAMAGE, 500C FIRE
Unbraced length = 37’-0”
E = 0.3*29000ksi = 8700ksi
Pu = 139k
Pn = 465k*0.5 = 233k
Mn = 4645 kip*in *0.5 = 2323kip*in

Mu = P*a
Mu = 6kip*1/3*37ft
Mu = 74kip*ft or 888 kip*in

Deflection = P*a *(3L^2 – 4*a^2)/(24*E*I) (Formula from AISC LRFD 3rd)
a = 1/3*L
= P * 1/3L *(3L^2 – 4/9*L^2)/(24*E*I)
= 23*P*L^3/(1296*E*I)
= 23*6k*(37ft*12in/ft)^3/(1296*8700ksi*739in)
= 1.45in

Additional moment due to P-delta
Mu+ = 1.45in*139k = 201.6 kip*in


Additional Deflection = Mu+*L^2 / (4*EI)
= 201.6kip*in*(37 * 12ft\in)^2 / (4*8700ksi*739in^3)
= 1.55in


Additional moment due to P-delta2
Mu++ = (1.45+1.55)in*139k = 417 kip*in

Additional Deflection = Mu++*L^2 / (4*EI)
= 417kip*in*(37 * 12ft\in)^2 / (4*8700ksi*739in^3)
= 3.20in

This results in the column becoming unstable due to p-delta. This can easily be seen in that the deflection due to P-delta2 is double that of P-delta1. It can therefore be concluded that it was necessary for both fire and damage to result in the collapse of the towers.

Originally posted by ANOK
reply to post by longjohnbritches

 

Typical reply from someone who has no argument.

I want all my stars back.
The Momentum math is all that is nessessary. Case closed.
Only a fool would deny it.
Give it a try???
ljb

Originally posted by SimontheMagus

Originally posted by thedman
reply to post by coyotepoet

 

So what was "perfect" about the collapse of WTC 1,2, 7...?

Far from collapsing in "footprint" as often been claimed the debris from these buildings was thrown for
hundred of feet causing severe damage to adjacent structures

Collapse of WTC 1 damaged WTC 7 (350 ft away), smashed Winter Garden and hit World Financial Center
over 400 ft away

WTC 2 smashed 130 Liberty St (Deutsche Bank) and damaged it so severely had to be torn down. 90 West
St was set on fire, burning for for 2 days Only heavy masonry construction saved it

WTC 7 damaged Verizon building next door and caused partial collapse of 30 West Broadway (Fiterman
Hall) across street - it was torn down

The chaotic collapse of these buildings resulted in massive damage to all the adjacent buildings....

No one had ever collapsed a building anywhere near 110 stories previous to 911. There's a reason why areas are cleared around controlled-demolitions, usually much more than "hundreds of feet" even for small buildings. The reason? They are not "perfect". They are "controlled". Perfect is a relative word in these situations when the results are compared to what would happen in an uncontrolled collapse.

130 Liberty Street was not torn town because of damage, it was torn down (beam by beam) because of toxic mold. And while you mention it, that building had very bizarre damage... a photo was taken of one of the beams that was hit by the south tower debris and the severed end of it was melted and twisted like a corkscrew. Evidently that jet fuel had even more magical properties than we thought. It managed to keep the pools of steel in the ground zero bathtub molten for several weeks.

I don't know how you OS'ers persevere.... it's like bailing out of the Titanic with a shot glass.

edit on 17-4-2012 by SimontheMagus because: (no reason given)

edit on 17-4-2012 by SimontheMagus because: (no reason given)

Hi si,
Good points.
It was also the internal explosions blowing that facia material out into the street. BOOMB!! pop! pop! pop! Worlds greatest demo feat.
cheers ljb
PS at least thed figured out why the Titanic really sank

Originally posted by -PLB-
So you still don't grasp the difference between static load and dynamic load, after it being explained dozens of time. And you asked for proof that you are clueless about physics? Can you show me anyone who has a background in physics who does not agree that your display in this thread is proof beyond any doubt that you are clueless?

No, you can't grasp that it doesn't matter.

All collisions between two objects is a dynamic load. The laws of motion apply to dynamic loads. Static loads do no move.

You are making no sense trying to make this claim. Sorry again you simply prove you fail to understand lol.

reply to post by Six Sigma


What a load of impressive looking nonsense.

Can you explain how the 5/8", and 1", bolts did not fail when the SAGGING trusses pulled the columns in?

If those connections were stronger than the columns, then why did they fail after the columns were pulled in?

Can you actually address anything I say with your own words instead of dodging them by appealing to authority that does not answer my questions?

Originally posted by longjohnbritches
I want all my stars back.
The Momentum math is all that is nessessary. Case closed.
Only a fool would deny it.
Give it a try???
ljb

Sorry that wasn't supposed to be directed at you, and I forget now why I posted it lol.

It was in response to something someone said to you, but what I forget.

Originally posted by Six Sigma
Continued:


As seen, the first p-delta iteration results in an increased deflection of 0.140in. The second results in a deflection of only 0.184in. We can thus conclude that p-delta will eventually converge and that no further iterations are necessary. The 6kip pull-in force with no effect of fire will not result in the column becoming unstable.

Hence no collapse.
Remember no total void no total velocity.
REMEMBER 2F=MA Your total math package above proves that.

BOOM poppoppop ljb

Originally posted by ANOK
reply to post by Six Sigma

 

What a load of impressive looking nonsense.

Can you explain how the 5/8", and 1", bolts did not fail when the SAGGING trusses pulled the columns in?

If those connections were stronger than the columns, then why did they fail after the columns were pulled in?

Can you actually address anything I say with your own words instead of dodging them by appealing to authority that does not answer my questions?

You just proved to me that you didn't read it. You have just proven to all of us that you are a troll. Perhaps a truther will be able to point out the answer for you.

Originally posted by longjohnbritches

Originally posted by ANOK
reply to post by longjohnbritches

 

Typical reply from someone who has no argument.

I want all my stars back.
The Momentum math is all that is nessessary. Case closed.
Only a fool would deny it.
Give it a try???
ljb

Please provide a working example of the "Momentum math" to support your position.

The term "implosion" was coined by my grandmother back in, I guess, the '60s. It's a more descriptive way to explain what we do than "explosion." There are [sic] a series of small explosions, but the building itself isn't erupting outward. It's actually being pulled in on top of itself. What we're really doing is removing specific support columns within the structure and then cajoling the building in one direction or another, or straight down. ” —Stacy Loizeaux, NOVA, December 1996

Stacey Loizeaux, twenty-six years old, has worked for Controlled Demolition, an international explosives engineering firm, since the age of fifteen. She learned the fine art of demolition from her father, Mark Loizeaux, and her uncle, Doug Loizeaux—president and vice-president of the company. NOVA

I don't know, make your own conclusions.

Originally posted by Drunkenparrot

Originally posted by longjohnbritches

Originally posted by ANOK
reply to post by longjohnbritches

 

Typical reply from someone who has no argument.

I want all my stars back.
The Momentum math is all that is nessessary. Case closed.
Only a fool would deny it.
Give it a try???
ljb

Please provide a working example of the "Momentum math" to support your position.

It is already posted in the thread or look on wiki Momentum (framed)
It's the latest model.
ljb

Originally posted by DrEugeneFixer

Originally posted by longjohnbritches

If the time stamp is a nano second before Building Seven Falls into it's OWN FOOT PRINT??
Then I will say DEMOLITION CHARGES.

First off, that is obviously not building 7, so whatever.

Second- what kind of demolition charges slowly pull the perimeter of a building's structure inward?

My bad on the building number. It is not a pull but a cross sectional demo charge. Notice the siding flapping in the breeze. That is from the simultaneous
detonation of squibs inside the building. Some further down the building actually BLEW huge hunks of the concrete veneer hundreds of feet.
YOOZAAA BOOM bam bam bam pop pop pop.
ljb
PS if you can scour all the demolition videos you will probable see lots of those cross sectional blasts.

Originally posted by longjohnbritches
[
It is not a pull but a cross sectional demo charge.

You're just making this up.

Originally posted by longjohnbritches

Originally posted by Drunkenparrot

Originally posted by longjohnbritches

Originally posted by ANOK
reply to post by longjohnbritches

 

Typical reply from someone who has no argument.

I want all my stars back.
The Momentum math is all that is nessessary. Case closed.
Only a fool would deny it.
Give it a try???
ljb

Please provide a working example of the "Momentum math" to support your position.

It is already posted in the thread or look on wiki Momentum (framed)
It's the latest model.
ljb

No you did not, you quoted part of a wiki article you clearly don't understand and then wrote a paragraph of nonsense.

Please show the work and how it supports your position....

reply to post by itsmethegoat


Actually, I know that company. They bid on a couple of my projects. The reason they like to use the term "implosion" is public relations. Who wants an explosion 5 blocks from their house? But say the word "implosion" and it sounds like its all going to be contained and safe. But she's right, its all really explosions, nothing accelerates inward.

Originally posted by longjohnbritches
That is from the simultaneous
detonation of squibs inside the building. Some further down the building actually BLEW huge hunks of the concrete veneer hundreds of feet.
YOOZAAA BOOM bam bam bam pop pop pop.

YOOZAAA BOOM bam bam bam pop pop pop?

Were these noises translated from sign language? Where these the Richard Gage "hush -a - bombs"?

Or , was this the Pebbles Flintstone on a date with Barney's son?

Originally posted by longjohnbritches

 

Remember no total void no total velocity.

Nothing other than more nonsensical B.S. that you have made up.

What is under discussion is whether the Inertia and momentum of the falling mass is sufficient to unbalance the resisting force presented by the materials and design of the remaining structure via impulse delivered by the impact.

The term total velocity means net force, the product of the sum from all of the combined velocity components of a mass, not top speed.

Terminal velocity is the point at which the acceleration of a mass stops due to a resisting force equaling the applied force, such as the resisting force of atmospheric drag equaling the applied force gravity to limit a parachutes decent.

REMEMBER 2F=MA Your total math package above proves that.

Wrong again, it is simply F=ma (where force in newtons is calculated by multiplying the objects mass in kilograms by the objects speed in meters per second squared.) not 2F=MA

Big M means moment of force, small m means mass.

Big A means area, small a means acceleration
Acceleration is measured in m/s², the force component is not squared.

As I clearly explained a few pages back, impulse is a product of momentum over time. Impulse does work, frame of reference does just what as says, is an observational reference tied to the state of motion of an observer.

The momentum of a moving car is different depending on whether the frame of reference of an observer is standing by the road or driving in another car alongside.

Originally posted by longjohnbritches

 

It was also the internal explosions blowing that facia material out into the street. BOOMB!! pop! pop! pop! Worlds greatest demo feat.

You haven't worked a day of your life on a job-site, have you?

You are incorrectly using another basic terminology. The exterior facing is most commonly called sheathing or cladding, decoratively it is referred to as the facade. Fascia is a specific term and applies to something else entirely.

In classical and commercial architecture the word fascia refers to a horizontal band at the top of a structure, the working contemporary residential terminology specifically refers to the board nailed across the rafter tails that your gutter is attached to.

You wouldn't know fascia from a footing, how are you qualified to call others ignorant.

Originally posted by longjohnbritches

Originally posted by samkent
If I may suggest a point.

If the trusses were overloaded with debris from another floor and or plane parts then they will sag. Regardless of the fire.
If the exterior columns were severed by the plane AND the trusses were overloaded would you not expect the exterior to be pulled inward below the cut point?
As per the picture.

Absolutly NOT. The building would bend to the exterior and fall from that point.
Like a hunk of your icecream cone.

Absolutely wrong, overloaded trusses fail and pull their walls inward by the connections all the time.

You don't have the slightest idea how any of this works and you are lying.

Originally posted by longjohnbritches

 

It is not a pull but a cross sectional demo charge.

You are either grossly misinformed or lying again.

Notice the siding flapping in the breeze. That is from the simultaneous
detonation of squibs inside the building. Some further down the building actually BLEW huge hunks of the concrete veneer hundreds of feet.

Your "squibs" are caused by the air over-pressure being forced out of the collapsing internal spaces of the structure.

There were over a quarter of a trillion joules of potential energy stored in WTC 7. That is the equivalent to something like 50 tons of TNT. What do you believe happened to it?


Laughably, the NIST report felt it necessary to address the controlled demolition accusations....









That looks conclusive to me...

PS if you can scour all the demolition videos you will probable see lots of those cross sectional blasts.

Lets start here...



......?

Originally posted by ANOK
No, you can't grasp that it doesn't matter.

All collisions between two objects is a dynamic load. The laws of motion apply to dynamic loads. Static loads do no move.

You are making no sense trying to make this claim. Sorry again you simply prove you fail to understand lol.

You either don't understand the relevance of dynamic load, or you are denying the reality that the WTC towers were hit by planes and burned for over an hour. Else your statement

A building can hold more weight than they are required to hold during its service life. So it is impossible for it's own weight to cause it to collapse.

makes completely no sense, as nobody is claiming that just it's own weight caused it to collapse. Make your pick.

Originally posted by ANOK
reply to post by Six Sigma

 

What a load of impressive looking nonsense.

Can you explain how the 5/8", and 1", bolts did not fail when the SAGGING trusses pulled the columns in?

If those connections were stronger than the columns, then why did they fail after the columns were pulled in?

Can you actually address anything I say with your own words instead of dodging them by appealing to authority that does not answer my questions?

I already addressed this issue twice. You ignored it twice. Your understanding is, of course, completely flawed. Try to figure out why it is next to impossible to break a match buy pushing or pulling the ends, while it is very easy when you hold it between your fingers and push it from the side.

Just to get the position of the truthers here straight: you guys think that the observed bowing inward of the perimeter columns was caused by explosives? Please answer "yes" or "no, I think it was caused by ".