[Aktungbby]

the 58 floor building was found to be sinking and tilting, perhaps as a result from developer cost-cutting by driving piles only 80 feet deep, and not 200 feet into bedrock. An examination in 2016 showed the building had sunk 16 inches with a two inch tilt towards the north west. The TJPA says the 60-story Millennium Tower is made of concrete rather than steel, "resulting in a very heavy building. This heavy structure rests on layers of soft, compressible soil. The foundation of the Tower, however, consists only of a concrete slab supported by short piles that fail to reach the bedrock below. That foundation is inadequate to prevent settlement of a building with the weight of the Tower." Instead of steel anchored on bedrock more than 200 feet down, it's made of concrete, sitting on a slab with pilings just 80 feet into the soil.

I watched this go in just a block from my 30 floor court bldg just South on Beale Street @ Mission. Old ships are still found buried in the mud around there (two blocks in from the Bay front) but the 'bedrock' is solid. I suspect that it will not become a leaning tower of Pisa. At 10' per floor: (when it 'hits the bedrock' 120 feet below)...it will be a perfectly nice 46 floor building with 12 new basement levels! https://en.wikipedia.org/wiki/Millennium_Tower_(San_Francisco)