Mr. Fall Down Terror posted:

regarding the building, the empire state building is way "overbuilt" for what needs to be. it is made of a bunch of heavy steel and masonry, as was the style of early skyscrapers. in fact, from the period 1880-1920 skyscrapers were evolving quickly as architects learned more about how to engineer and build ever taller buildings. remember that all of this work was being done without computers, being drafted and calculated by hand, so the safety factor was a bit larger than architects use today (if we think of safety factor as extra materials, thus extra cost, you want to shave this down a bit but not too much, for safety). as tall buildings shifted from all-masonry, to masonry supported by steel, to a steel/masonry hybrid, architects were busy figuring out optimal balances of both. you can really only build about 10 stories tall with all masonry construction, before the bottom walls are too thick to have windows or doors. (10 stories is already above the practical limit of daily stair climbing, this is why poor people before elevators lived in the attic) steel lets you get a lot, lot taller, shifting the structure of the building from internal masonry supports to a steel skeleton with a masonry wrapper

the empire state building itself was also caught up in a roaring twenties race to have the tallest building. as architects got better at building bigger, then everyone wanted to have the biggest building. especially everyone in new york, it was a for real race to have the biggest dick in town. the plans for the empire state building and its immediate precursors kept getting taller and taller, so there's a bit of 'extra' in the design just in case yet another set of revisions came along trying to stack another five floors on top. while the empire state building is near the limit of practical engineering for the time, the main reason it was capped was because it was already The Tallest and also there was concern that additional floors would be increasingly difficult to rent, so they capped the whole thing off with a ridiculous zeppelin mooring mast and signed off

in comparison, the WTC is a hallmark of late international modernist design. instead of the empire state, which is basically a shitload of interlocking steel girders with a heavy masonry shell, the WTC 1 and 2 were a very tall core pillar of elevator and service tubes, around which a bunch of floorspace hung. imagine a giant concrete tree trunk, encased in a thin steel and glass truss. on neither building was the outer shell structurally supportive, but with the WTC the outer skin handled stress redistribution and wind load more than the outer skin of the empire state building, which was primarily decorative and to keep the weather out. both buildings are well designed, but the WTC 1 and 2 towers could be bigger and have more floor space relative to the cost, which is your goal when you're building an enormous tower

now, regarding the planes. the plane which hit the empire state was a ww2 vintage b-25 medium bomber. this plane had two propeller engines, had a maximum weight of 30 tons fully loaded, and a maximum speed of about 270 mph. both the WTC towers were struck by variants of the boeing 767, a modern jetliner which has a max speed roughly twice as fast, and a maximum weight roughly five times greater than the b-25, depending on configuration. the 767 is a modern, much bigger, much faster plane

the b-25 which hit the empire state building was transporting people between military bases when the pilot became disoriented in a thick fog over new york. he took a wrong turn and flew right into the side of the empire state building. the plane was not fully loaded, it had no weaponry on board and an adequate but not full load of fuel. the pilot was flying at a slow rate of speed because he was navigating in poor visibility over a city, and so he slowed down a bit to try to figure out where he was and also, to not crash into anything

in comparison, the hijacked 767s were fully loaded with fuel. the hijackers specifically targeted cross country flights because they would have more fuel, because due to the fact that lugging fuel around costs fuel and thus money, common aeronautical practice is to just put in as much fuel as you need to get to where you're going plus a bit extra to be safe. a flight going from NYC to boston will have much less gas on board than one going from NYC to LA. the hijackers then flew these fully loaded planes at maximum speed into the towers in broad daylight, for maximum damage

both buildings were completely penetrated by aircraft debris. because the empire state building had thicker walls, relatively heavier internal construction, and was struck by a smaller plane traveling at a slower speed with less explosive potential, the amount of damage done to the building was relatively lesser. the damage was mostly localized to the immediate location of the strike. on the other hand, both WTC 1 and 2 were struck by aircraft roughly five times larger, traveling roughly five times faster, and with a much larger quantity of explosive fuel on board. this damage was spread all through the building. in all cases, the aircraft strikes started fires, but because of the massive damage done to the internal core of WTC 1 and 2, fire response was unable to begin fighting the fire before the structures collapsed

the heavier masonry walls and lighter force applied meant that the damage to the empire state building was never critical. a dozenish people died, mostly due to the immediate strike, which took out two adjoining office suites on a high floor and set them on fire. the structure of the building was not compromised, and the repairs were largely cosmetic. on the other hand, both WTC towers found their internal cores completely severed due to the speed and violence of the aircraft strike, which had a number of effects

-it compromised the ability of victims to escape, and first responders to assist
-it compromised the structural integrity of the building itself
-it allowed fire to spread from the immediate site of the impact (which was itself much larger) into adjacent areas

that's about as good of a summary as i can spit out. total apples to oranges when it comes to aircraft flying into buildings and killing people