It’s built on a landfill. A garbage dump. The tallest and probably the most massive building in San Francisco is built on top of a garbage dump. They built it on top of a garbage dump. I can’t get my head around it.
I’ve been to a few garbage dumps. They take truckloads of household garbage plus all sorts of junk and put it in a huge hole and drive bulldozers all over it to squash it down. I can imagine forty feet of plastic garbage bags full of dirty diapers, milk cartons, metal cans, and paper towels. Coffee grounds. Rice, bacon grease, egg shells. This stuff decays at different rates. Metal rusts away and the space inside the can fills with water. There must be at least 15% of the volume as trapped air. Then water seeps in from runoff and percolating down into the soil. Methane is a byproduct of dumps as the garbage decomposes. Wood, paper and food are all mostly cellulose which is carbohydrates. The carbohydrates decay into water and methane.
I don’t see how this could be considered stable by any stretch of the imagination. They would have had to sink pilings deep into the ground all the way through garbage and well into any bedrock below. That’s a lot of pilings to support the building and they would have to have supported the entire structure above the garbage knowing that the garbage would not support any weight.
If it doesn’t fall over it will be a miracle. If an earthquake happens before they get it fixed up they could be screwed.
They did the same with the Embarcadero center buildings (4 office towers) back in the 80s, and those have been standing for 40 years. And 1 California, the weird Hilton hotel at the end of Market St., etc.
There are quite a lot of South of Market high rise developments that are on the same soma landfill.
None were as extreme as this one though.
How appropriate. Built on a garbage dump within a much larger garbage dump of a city.
The real problem as I u defer and it is they convinced themselves that they did not need to place sufficient anchors down to bedrock but instead took a less extensive and therefore less expensive option
There are several other buildings in the area that have also been supported this method(friction pilings). Yes, it is on landfill. So, is the entire BACK BAY section of Boston. Where the 55 story Prudential Center and the 60 story John Hancock building have sat since the 1970s. The difference being in Boston that the Charles River Back Bay had SOLID ROCK underneath it.
The original ground underneath the tower in San Fran is on the land fill from the earthquake that destroyed the city in 1905.
The original ground/bedrock was 200 feet below the current street level. So, they used friction pilings. A method that had been employed by many other structures in the area.
FYI, many parts of Manhattan are also landfill. That is why the really tall buildings are at the southern tip where the Twin towers once stood and from 23rd street(Empire State Building) and up through mid town. Greenwich Village buildings are only 4 stories high because the ground underneath there was wetland back in the 1600s. It is all landfill.
LOL....”which was built atop a former landfill”...This is where I stopped reading. I wouldn’t build a garage over a landfill and I’m not an engineer. Just a guy with common sense!.