Bifalgorithm post

A few columns holding up a 30-story building. What kind of structure is that and why would anyone build it that way? When we design a residential tower, the usual approach is to drive a cluster of piles and pour a raft foundation, then erect the building right on top of it. But if that same building sits in prime real estate like New York, where the lower floors have huge commercial value, running all the sheer walls straight down to the ground would kill any chance of a large open retail space on the lower levels. And that's a massive loss of revenue. That's when the structural engineers step in with a clever move. What if we take that raft slab, lift it up in the air and support it with a few massive columns, then we build the residential tower upward from that elevated slab. Suddenly, the ground level is wide open, perfect for commercial use. But here's the catch. A design like that is top-heavy and under-supported at the base. What engineers might call the "chicken leg effect". One decent earthquake could spell disaster. However, don't forget, people upstairs still need to get down. So what if we cut an opening in that thick slab, drop the vertical circulation all the way to the ground, and thicken those sheer walls to form a huge central core? That core not only stiffens the otherwise fragile base but also handles fire safety and traffic flow. This is the thick slab transfer structure that combines premium residential space with high value commercial real estate. So when a master structural engineer gets to work they basically borrow another building out of thin air.

A few columns holding up a 30-story building. What kind of structure is that and why would anyone build it that way? When we design a residential tower, the us…