[streetpreacher]

instead of bracing the buildings corner-to-corner or using internal walls, the towers were essentially hollow steel tubes surrounding a strong central core.

Why no mention of the 47 central steel columns that were the main support for each tower?

[SauronOfMordor]

Why no mention of the 47 central steel columns that were the main support for each tower?

That's the "strong central core" that was being talked about. See pic below: