I was walking through London when I saw...

[wakeup]

Opposite the Lloyds building in London at the moment they're demolishing 112 Leadenhall street to make way for "the Cheese Grater". But take a look at how they're doing it.

http://globalnix.blogspot.com/2007/06/demolition-of-122-leadenhall-str eet.html
http://www.flickr.com/photos/globalnix/589924997/

They're demolishing from the bottom, floor by floor, but leaving the core intact. For all those who point to the 'huge gouge' taken out of the base of WTC7, it surely can't compare to this.

[Disco_Destroyer]

You have it all wrong, no demolition the floors just Pancaked

[wakeup]

Surely they must have done; but oh damn, the core still remains

[Disco_Destroyer]

Hehe well thats the one bit they couldn't remove first

[James C]

This picture is amazing, just goes tgo show you what can be done to demolish a building.

We must be careful not to get too excited by examples such as this however since this building employs completely different constructional and structural techniques to the Twin Towers and WTC7. For a start, this building has a concrete structure; concrete core with cantilevered reinforced concrete floors. The outer walls are non-loadbearing glass and metal cladding. This is why the floors can be removed one by one. I assume that they started from the bottom and are working upwards in order to free up the ground so that preparations can start for the new building. Time being money and all that.

On the other hand, the Twin Towers and WTC7 were all steel buildings. WTC7 was a standard framed building , i.e. columns placed strategically across the whole plan. But the Twin Towers used a structure which had been used only once before and few times since whereby the inner core was structural and so were the outer walls (unlike in the example above). The (non-cantilever) lightweight floors then spanned between these elements. It certainly wouldn't have been possible to remove the lower floors and facade of the Twin Towers as it would have caused the floors and walls above to collapse. However, when the towers fell, they fell very strangely (as we all know) considering that the facade was independent of the core. For instance, if by some miracle the steel core had undergone a vertical progressive collapse, an impossibility of course, then it would have pulled the facade inwards as it fell since both structural elements were connected by the floors. This is not what was observed and the facade appeared to blow outwards as it fell showering the streets below with concrete dust. This just wouldn't have happened.

As for WTC7, if indeed a significant loss of the facade had caused structural failure, then it would have toppled over sideways towards the point of failure. Again, this did not happen and the clean vertical fall was clear evidence of structural failure across the whole plan simultaneously. Again, an impossibility by natural means.

[wakeup]

Sure, you're right.

It would be foolish to draw direct comparisons between this building and any of the WTC towers, largely for the reasons you mentioned.

Nonetheless, from a casual observer's perspective I think it's still interesting to see that superficial damage to a building does not necessarily mean that structural integrity is compromised.

As a point of interest a friend in Lloyds informs me that they started demolishing from the middle downwards, and that there are construction workers in the upper floors of the building on a daily basis (so it's still perfectly safe).

[Disco_Destroyer]

No comparisons just trying to make lite of a horrible situation. I do however dispite all thats going on maintain this Grab for World Power will fail in the long run