If I remember correctly the central core of the structure was the main support. The surrounding floors/walls etc were tied to this by triangular struts, which normally would provide a good load bearing, (think-roof trusses).
On impact a lot of these cross supports would instantly have disintergrated leaving heavy concrete floors/ceilings spanning a gap which was too wide to support their weight. The result was that these floors/ceilings then began to sag towards the centre of the building before reaching their breaking point and crashing onto the lower floors.
This combined weight would then start to bring the whole structure down like a pack of cards. Now, bearing in mind that these floors would also have a lot of heavy equipment on them from computer terminals/filing cabinets/desks and a host of other commercial equipment, not to mention electrical distribution sectors, elevators and asociated motors and control gear then you are talking about some serious weight issues.
By collapsing towards the centre this actually may have saved lives by collapsing into a relatively small footprint. Imagine how many more may have been killed if they had 'toppled' over so spreading their destructive force over a wider area and bringing down some of the surrounding buildings.
As for the emergency services going in, it is in their nature to put the lives of others over everything else. They weren't bothered about the building they were concerned with saving lives, sadly it cost a great many of them theirs.
As WOBS says, 'Such bravery by so many'.
We should all have the greatest respect for these people and utter contempt for the perpatrators.
On impact a lot of these cross supports would instantly have disintergrated leaving heavy concrete floors/ceilings spanning a gap which was too wide to support their weight. The result was that these floors/ceilings then began to sag towards the centre of the building before reaching their breaking point and crashing onto the lower floors.
This combined weight would then start to bring the whole structure down like a pack of cards. Now, bearing in mind that these floors would also have a lot of heavy equipment on them from computer terminals/filing cabinets/desks and a host of other commercial equipment, not to mention electrical distribution sectors, elevators and asociated motors and control gear then you are talking about some serious weight issues.
By collapsing towards the centre this actually may have saved lives by collapsing into a relatively small footprint. Imagine how many more may have been killed if they had 'toppled' over so spreading their destructive force over a wider area and bringing down some of the surrounding buildings.
As for the emergency services going in, it is in their nature to put the lives of others over everything else. They weren't bothered about the building they were concerned with saving lives, sadly it cost a great many of them theirs.
As WOBS says, 'Such bravery by so many'.
We should all have the greatest respect for these people and utter contempt for the perpatrators.
