This puts any of our challenges into perspective

[saveasteading]

"  it’s a steel frame building, so it would not be a total collapse. It would be more of a localised collapse.   "

 

Wishful thinking perhaps, or some words to keep the shareholders and banks happy?

 

Steel buildings can collapse. There is an inherent ability for them to crumple and come to some sort of stability if there is a localised failure. But I don't think this was designed for back in 1960.

in Europe we have to design to prevent "disproportionate collapse" ie one failed element, eg from a gas explosion, would cause only local damage.

see Ronan Point 1968 

 

 

34 minutes ago, ProDave said:

the collapsed columns were likely not reinforced properly and could not support the weight above

That's a fire officer... 

[SteamyTea]

6 minutes ago, saveasteading said:

see Ronan Point

There is a great documentary about RP. One of the contractors still found it funny how they got paid more to put less bolts in. Wankers.

 

8 minutes ago, saveasteading said:

"disproportionate collapse"

Wish I had known that was a 'thing when I was studying engineering. It would have been a hard sell in some companies I have work for, but the opportunity to build models and then destroy them would be great.

[ProDave]

I was surprised at the total collapse of the twin towers of 9/11.  I would have expected the fire compromised floors might just have collapsed down leaving the largely undamaged floors above and below intact.  I can only guess that when one floor collapsed, the momentum of the structure above put too much force on the floor below when it "landed" on it and so a chain of events started.

[SteamyTea]

1 hour ago, ProDave said:

I was surprised at the total collapse of the twin towers of 9/11.  I would have expected the fire compromised floors might just have collapsed down leaving the largely undamaged floors above and below intact.  I can only guess that when one floor collapsed, the momentum of the structure above put too much force on the floor below when it "landed" on it and so a chain of events started.

Maybe the 900 GJ of chemical energy per plane had something to do with it.  That is about 200 tonnes of TNT.

And that is before the kinetic energy of the impacts.  About 200 MJ, about 50 tonnes of TNT.

 

[saveasteading]

2 hours ago, SteamyTea said:

the opportunity to build models and then destroy them would be great.

 

This happened in my uni year one. Tiny portal frames tested to destruction, and thus stuck in my mind thereafter that a frame needs 3 'pins' to form.

(You can see that in the photo... top, middle bottom have all rotated.)

If it had simply been 10 minutes of a lecture it wouldn't have had the same effect.

 

 

1 hour ago, ProDave said:

the momentum of the structure above 

Dead load becomes dynamic load. Also that the loading of the remaining structure becomes out of balance, and in the RP example  the floor collapses are accumulating to be ever increasing  loads.