It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Thank you.
Some features of ATS will be disabled while you continue to use an ad-blocker.
Originally posted by DrEugeneFixer
reply to post by ANOK
what was the safety factor?
What is a Margin of Safety?
Every machine, building and piece of infrastructure is intended to function correctly within a certain range of factors. Weight, temperature, pressure, vibration, quality of contstruction, durability of materials, and climate factors all affect safety. Most buildings and equipment are engineered to ensure that the ability to respond to extreme changes in any of these factors far exceeds the failure point. Engineers are expected to adapt building plans to account for various failure scenarios such as overloads, deliberate destruction or weather.
Buildings commonly use a factor of safety of 2.0 for each structural member. The value for buildings is relatively low because the loads are well understood and most structures are redundant.
Originally posted by ANOK
reply to post by DrEugeneFixer
Do you want to discuss physics, or waste my time with semantics?
x2 is a minimum for a component, many components welded and bolted together increases the overall redundancy of the structure. x2 is quoted because its the minimum and you can't argue that is would be less, and it's more than would be needed in order to arrest the collapse of falling floors.
This get real old when I have to explain every tiny detail because you come to the discussion thinking you know everything, then you show you fail to understand the basics of structural engineering and physics.
So you honestly think that if you removed the second story of a building, hoisted it say 20 feet in the air above the bottom half the building, and let it drop, the first story would not be pulverized by the weight of the second story despite its having held that weight previously?
You can't claim that the falling of the material is causing the lower structure to fail AND that it is causing the crushing. To be crushed the material needs to be resisting the collapse, otherwise it can't be crushed.
There are some estimates which claim that two thirds of the buildings were reduced to dust.
Considering the relatively small debris pile, this is a valid estimate.
How can all this dust crush two massive skyscrapers to the ground?
The answer is easy: it cannot.
The towers were blown to smithereens, not crushed, as anyone with one functioning eye can see from the videos.
Originally posted by ANOK
Originally posted by defcon5
reply to post by ANOK
Because bolts and welding offer little to no resistance by comparison to the vast amount of weight that is dropping straight down on top of it as the upper stories slam down on top of them.
If it make you feel better put a few small dabs of white glue on the edges of the cards, but you’ll still end up with the same result. A house of cards will collapse in the exact same manner as a truss constructed building.
The building was designed to hold its weight plus a safety factor that would allow the building to hold its own weight many times over. So sorry but there was no reason at all the building would completely collapse from its own weight. The laws of motion tell us that 15 floors can not crush 95 floors.
Originally posted by buddhasystem
What laws of motions (and which laws precisely, and by what quantitative result) tell us that 15 floors can not crush 95 floors?
Originally posted by DrEugeneFixer
reply to post by ANOK
Go ahead and keep pretending to know physics and engineering, ANOK. You're not fooling many with your links to E-How and pediaview.
We can discuss physics all you like, but it is awfully hard to do much of that without at least a little math, which apparently scares you. I have yet to hear your explanation beyond "its obvious...newton's laws...blah,blah,blah." Just go ahead and lay out your explanation in detail.
Newton's third law applies to pairs of bodies. If a body A exerts a force on a body B, then body B exerts an equal and opposite force on body A.
The Importance of Newton's Laws
Newton's laws are extremely important not just in mechanics but in the whole of physics. When trying to understand a physical process, we often understand it by looking at the forces acting and working out the equations of motion. This is true of the motion of the planets to the flow of electrons in an electric or magnetic field.
Originally posted by ANOK
Originally posted by buddhasystem
What laws of motions (and which laws precisely, and by what quantitative result) tell us that 15 floors can not crush 95 floors?
The 3rd law, equal opposite reaction.
When two objects collide the forces on each object is equal. We know the floors were being destroyed during the collapse. The dropping floors can not stay in one piece, while destroying the floors they were dropping on.
Even if I'm generous and allow two static floors to be destroyed per one dropping floor, 15 floors falling on 95 that still leaves 65 floors that should have been stacked in the footprint.
Momentum conservation tells us that both the dropping floor and the static floors will want to maintain their momentum and will push against each other with equal force.
This is simple basic high school physics.