Demolition Monitor Disputes CD Theory

[dontdrinkurmilk]

Originally Posted by marky78

I think I'm going to try and stop responding to you milky to try and put and end to this merry-go-round.

Fair enough, I suppose whilest your away you should read up on dynamic loads and what they are.

Just before you go, that table you cited was that for WTC 1?

[rosie789]

You know Marky I've been talking about physics all day and I brought up some of the things here in conversation. The simple answer that we could all agree was that a floor would simply not provide enough force to change the momentum of the falling mass so that the collapse would stop.

We also started talking about tornadoes and how blades of grass can be buried in trees. Amazing.

[skanny]

Originally Posted by rosie789

You know Marky I've been talking about physics all day and I brought up some of the things here in conversation. The simple answer that we could all agree was that a floor would simply not provide enough force to change the momentum of the falling mass so that the collapse would stop.

We also started talking about tornadoes and how blades of grass can be buried in trees. Amazing.

oh thats me sold then ......

random unknowns agree that a floor would simply not provide enough force to change the momentum of the falling mass so that the collapse would stop.


now is it just me or does anyone else call nonsense on rosies ramblings?


***( drunk in charge of a keyboard )***

[dontdrinkurmilk]

Originally Posted by rosie789

You know Marky I've been talking about physics all day and I brought up some of the things here in conversation. The simple answer that we could all agree was that a floor would simply not provide enough force to change the momentum of the falling mass so that the collapse would stop.

We also started talking about tornadoes and how blades of grass can be buried in trees. Amazing.

Quite right, its amazing what can happen to things at high speeds. I think the 31 times the static load was an error in judgement as Marky has said. Never the less the resistive force is less than the force of gravity on the top section, hence why it accelerated downwards.

[rosie789]

Originally Posted by rosie789

You know Marky I've been talking about physics all day and I brought up some of the things here in conversation. The simple answer that we could all agree was that a floor would simply not provide enough force to change the momentum of the falling mass so that the collapse would stop.

We also started talking about tornadoes and how blades of grass can be buried in trees. Amazing.

By the way I should probably mention that this effect of tornadoes is not fully tested, however people have managed to drive splinters into bricks:

With a specially designed cannon, wind engineers at Texas Tech University have fired boards and other objects at over 100 mph into various types of construction materials, duplicating some of the kinds of "bizarre" effects, such as wood splinters embedded in bricks.

http://www.spc.noaa.gov/faq/tornado/

Hmmm... well I don't know about 31 times the static load.

A fairly crude demonstration:
lets say just one floor of the building is compromised, and so the upper block (starting from rest) accelerates downwards for three metres at 9.8m/s^2:
v = 7.7 m/s (2sf)
now let's say the upper block has mass n tonnes:
momentum = mv = 7.7n
now assume that this momentum must be reduced to zero in 0.2 seconds to stop the building from collapsing:
Force required = change in momentum/time
= (7.7n - 0)/0.2
= 38.5n

????? IDK

Used this page to calculate velocity after 3m.

http://hyperphysics.phy-astr.gsu.edu/hbase/flobi.html

[dontdrinkurmilk]

Originally Posted by rosie789

By the way I should probably mention that this effect of tornadoes is not fully tested, however people have managed to drive splinters into bricks:



http://www.spc.noaa.gov/faq/tornado/

Hmmm... well I don't know about 31 times the static load.



????? IDK

Its not easy to calculate, but its evident the mg was too much for the bottom section to resist.

[rosie789]

So does anyone still think the upper tower should have been arrested by the lower?

I'm sure it is the force of the upper tower which would destroy the floor, not the 'deceleration'. The deceleration is a product of the reactive force and not the other way around.

[skanny]

Originally Posted by rosie789

So does anyone still think the upper tower should have been arrested by the lower?

I'm sure it is the force of the floor which would destoy it, not the 'deceleration'. The deceleration is a product of the reactive force and not the other way around.

remember to stick a patent on your new found method of demolishing buildings by your groundbreaking piledriver, plane impact, office fire demo method.

do keep in touch with us to show just how well your new venture into controlled demolition works out for you, im positive you are clearly onto a winner.

[rosie789]

Originally Posted by skanny

remember to stick a patent on your new found method of demolishing buildings by your groundbreaking piledriver, plane impact, office fire demo method.

do keep in touch with us to show just how well your new venture into controlled demolition works out for you, im positive you are clearly onto a winner.

Using this method would be ridiculously dangerous since dangerous chemicals are released in fires

However during most controlled demolitions there is an element of a building falling on itself, whether it's bottom up, a few different points or top down (like verinage). Idea is taken I'm afraid.

For the really big ones which are surrounded by other buildings it's far safer to use reverse construction.

[marky78]

Originally Posted by rosie789

So does anyone still think the upper tower should have been arrested by the lower?

I'm sure it is the force of the floor which would destoy it, not the 'deceleration'. The deceleration is a product of the reactive force and not the other way around.

in the voice of Frank Carson

'it's a cracker'

[mishy]

[rosie789]

Originally Posted by rosie789

So does anyone still think the upper tower should have been arrested by the lower?

I'm sure it is the force of the floor which would destoy it, not the 'deceleration'. The deceleration is a product of the reactive force and not the other way around.

Agh sorry, the force of the upper tower which would destroy the floor. I was a bit tired last night. The deceleration is the product of the reactive force, it is not what causes the destruction.

[rosie789]

The falling top part of the tower has a momentum vector which is pointing downwards because it is accelerating due to gravity. When it hits the bottom section of the tower, the bottom section must apply a contact force to the top section which changes it's momentum (so it decelerates). The Newton's third law pair of this contact force is the contact force acting on the bottom section of the tower, this is what causes the damage to the bottom section of the tower.

The force required to arrest the upper tower would be equal to the required change in momentum of the upper block divided by the time in which this change is made.

Its really as simple as that and my brain goes mushy when I try to debate with you guys. You're just confusing everything.

I would get someone who's more qualified to talk with you (my friend or my Dad) but they've actually refused. Instead they're encouraging me to, but I'm just a music student. I mean most of the time I come to the same conclusions as them, but I tend to loose confidence.

[dave52]

Originally Posted by rosie789

I'm just a music student.

You would love Ace Baker's work. He's all about the music.

http://www.youtube.com/playlist?list=PLEA05F393EC843D80

[rosie789]

To put it more simply the force of the upper tower on the lower is equal to the force of the lower on the upper, however the resistive force of the floors is not enough to reduce the momentum of the upper tower to zero.

It is the force of the upper tower which destroys the lower (and vice versa) and the deceleration is only a product of the resistive force, the momentum greater when the object is moving faster.

The upper tower accelerates due to gravity. Some great mystery that is.... not.

David Chandler only tells people what they want to believe.

Originally Posted by dave52

You would love Ace Baker's work. He's all about the music.

http://www.youtube.com/playlist?list=PLEA05F393EC843D80

Oh very funny.

[skanny]

Originally Posted by rosie789

To put it more simply the force of the upper tower on the lower is equal to the force of the lower on the upper, however the resistive force of the floors is not enough to reduce the momentum of the upper tower to zero.

It is the force of the upper tower which destroys the lower (and vice versa) and the deceleration is only a product of the resistive force, the momentum greater when the object is moving faster.

The upper tower accelerates due to gravity. Some great mystery that is.... not.

David Chandler only tells people what they want to believe.



Oh very funny.

its not about "belief" .... there was NO PILEDRIVER!!!

[denton]

Originally Posted by skanny

its not about "belief" .... there was NO PILEDRIVER!!!

Do you believe explosives were used?

[rosie789]

Originally Posted by skanny

its not about "belief" .... there was NO PILEDRIVER!!!

I suppose you mean that there was no building falling on rest of building?

Really? Where did the mass go then? The resistive force is going to destroy and partly compress the upper tower while some of the debris would be propelled away with the energy of the collapse, however this would probably be balanced out by the mass of the floors which are being destroyed. That's what happens in a verinage collapse.

Edit: Well this is a roman 'pile driver'.

[skanny]

Originally Posted by rosie789

I suppose you mean that there was no building falling on rest of building?

Really? Where did the mass go then? The resistive force is going to destroy and partly compress the upper tower while some of the debris would be propelled away with the energy of the collapse, however this would probably be balanced out by the mass of the floors which are being destroyed. That's what happens in a verinage collapse.

Edit: Well this is a roman 'pile driver'.

really? where? probably? ... your posts im struggling to make head nor tails with tbh.
you show you dont know what you are talking about in all honesty, then you start mentioning verinage collapse in relation to the towers destruction.

NO PILEDRIVER and NO VERINAGE!!!

i would go on but i dont want to confuse you any further than you already are.


***( ignore list may show some rapid growth soon )***