>Friction piles are quite normal too. I've lived in buildings in SoMa that used friction piles and none of them were tilting as much as this building.

A selling point for my old condo building in SoMa is that it's one of the few buildings there that is built on bedrock.

The piles they used for the Millennium Tower were the same length—80 feet[0]—as those they'd use for a 22-story highrise on, say, 6th St. Millennium Tower is 58 stories and right on the water.

[0] (PDF, pg. 2) https://sfdbi.org/sites/default/files/Millennium%20Tower%20S...

A few years ago, one of the theories was construction of the transbay terminal caused this, but I have no idea if that was actually the case.

You can imagine why they floated that idea but the site is surrounded by other buildings which survived intact, including a 100-year-old unreinforced brick building.

Is it normal for the size of the building + use of concrete over steel (increased load)?

In other parts of the world, far taller buildings are constructed using friction piles[1].

Again, friction piles are not unusual at all. Drilling into bedrock happens in parts of Manhattan[2] , but that's because the bedrock is generally close to the surface.

Whatever's going on with Millennium Tower, it's not "friction piles bad".

1. https://youtu.be/N5i3UsiSoYY

2. https://buildingtheskyline.org/bedrock-and-midtown-i/