Some of the lower floors (20 to 60s range) in the new tower are apparently larger than those in the twin towers, while those in the middle of the tower are comparable to the 1 acre floor area of the twin towers. The upper floors have around half an acre of floor space. We now have one 3,501,274 sq ft tower, whereas before we had two that were 4,300,000 sq ft each. Overall, the total volume of the building is comparable, due in part to the "bigger butt".
It's not bad, considering there are less floors overall due to higher ceilings in the new one. If I'm reading the floor plans correctly, this building has 47,340 sq ft on the 45th floor, meaning the floors lower than that have a bit more area than the twin towers did, since 208 ft x 208 ft is only 43,264 sq ft. Unless the floor plans are wrong, the new tower has a silhouette of at least 220 x 220 ft, and the 200 ft x 200 ft figure that we were given doesn't quite add up.
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