reply to post by skeptic_al
I'm no expert on structural failure true, I just can't understand how it occurred in this case but those that are so definite it didn't occur
through some controlled mechanism offer no real explanation of how it did occur.
"Like anything be it plastic, wood, steel or concrete when something
is fractured it can no longer support what it was designed to do."
Agreed, and at that moment it fails, not 50 minutes later, but you can't compare damage in a multi composite structure to a stress fracture in a
"You could have a crack on car gearbox, it will still work for a while
then suddenly bam, catastropic failure."
A crack in a casting of a piece of machinery under varying loads is in no way applicable to this case.
"This applies to everything, my laptop could have small crack on the lid,
and one day bam it;s totally stuffed. Lids in one hand and keyboard in
Again, a crack in something that is then subjected to additional loads.
"There is also the Rostraver Ice Rink Roof collapse, the whole roof didn't
collapse at the same time. It would have been a progressive failure all
happening in a fraction of a second."
Again, example not applicable. Firstly the weight of the snow would be fairly equally distributed across the roof and acting equally on all supports.
When the weight of the snow exceeded the load bearing capability of the supports holding the roof it imploded, but what is important to note is that
the actual structural support for the roof remained standing.
In some ways this could be said to be similar to the collapse of a single section of floorplate of the tower on one floor. However we know that they
couldn't have collapsed all at the same time and the pancake effect just did not occur.
If the ice rink were 10 levels high then, depending on its construction, it is conceivable that the roof collapse could cause the collapse of levels
below. However the external structural supports of both roof and floors would remain.
What caused the collapse of the internal structural support initially at the level of impact and then almost simaltaneously for levels below ?
Even if it can be accepted that the levels below were simply crushed by the falling of the section above the initial collapse (which is a big "if"),
what caused that initial collapse ?
I guess the simple explanation is the easiest to grasp for most people, it was damaged at impact and just gave way in due course. However, this isn't
actually what happens. Structures (gearbox casings, laptops etc) either fail immediately upon receiving the damage, fail later upon receiving some
other loading or gradually get worse to the point that they fail later upon receiving some other loading.
It didn't fail immediately and there was no deformation as there would have been if it was getting gradually worse.
So what caused the structural support to receive some other loading ?
You can clearly see that there is a failure of the internal structrural support and a collapse begins. The external structural supports then simply
fail, being exposed to loads they are not capable of supporting. Even without discussing what happened from then on what was the cause of the internal
The only possible scenario I can think of is that the initial damage caused structural failure of a large part of the internal core but that the
external structural support was strong enough to stop any deformation. Subsequent weakening of truss's by fire caused failure and collapse of a
floorplate that was then the cause of the other loading on remaining internal supports so that they failed.
Is this what is being proposed ?