The Leaning Tower of San Francisco

#1
It's a new (2006) skyscraper filled with luxury condominiums (with extraordinary views). Some are owned by tech titans. Joe Montana, the SF retired 49ers quarterback has a condo there.

The building was built to code, but now it's copying another tower in Pisa Italy. It's currently sunk 17 inches into the earth and is tilting 14 inches sideways. The concrete in the basement areas is filled with ever-growing cracks. There's lots of concern about what might happen in a large earthquake. (I walk past this building all the time and the tilt isn't visible to the naked eye.)

Residents are behaving as San Franciscans always do when they can't blame Trump: They are suing. There are some 20 lawsuits currently, alleging that the value of the properties in the building has fallen some 50% from what the residents paid for the apartments. It hasn't been condemned and people still live there.

The building rests on landfill I believe, on piles driven into the soft soil. But the piles don't go all the way down to bedrock and appear to be sinking.

Things are complicated by the fact that the city is building an underground transit hub next door and it involves huge excavations and underground tunnels. So some of the lawsuits are the building's developers suing the city for screwing up their building's foundations. The city denies it. The developers insist that their building conforms to code and is basically the same foundation design as most of the surrounding towers have used.

But the city's most iconic new building (very close by) took the hint and assures everyone that its supporting piles do extend down to bedrock.

TV's 60 Minutes is doing a segment about the Leaning Tower of San Francisco.

https://www.cbsnews.com/news/as-san-fran...its-rises/

There were hopes that the sinking and tilting would slow down and stop, but that doesn't seem to be happening. So there are proposals to drive more piles down to bedrock (hard to do with an existing building) and that will likely cost $100-$150 million.

https://www.archdaily.com/876722/enginee...nium-tower

Otherwise they took all the precautions. The building is 58 stories high, but listed at 60 since the 13th and 44th floors were deleted for superstitious reasons (the word for the number '4' sounds like 'death' in Chinese).

But extend the piles to bedrock? No.
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#2
More and more cracks and shifts in the superstructure will occur over time due to the stresses of uneven gravity. I say sue the bldg owners for all they're worth.
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#3
The 60 Minutes segment on the Millenium Tower will be shown tonight on CBS at 7:00.
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#4
Wow...didn't go to bedrock. That story gave me vertigo just thinking about it.
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#5
(Nov 6, 2017 04:37 AM)Magical Realist Wrote: Wow...didn't go to bedrock. That story gave me vertigo just thinking about it.

The piles are just stuck down into the soft soil. The kind of soft soil that's prone to liquefaction in large earthquakes.
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#6
(Nov 7, 2017 05:35 AM)Yazata Wrote:
(Nov 6, 2017 04:37 AM)Magical Realist Wrote: Wow...didn't go to bedrock. That story gave me vertigo just thinking about it.

The piles are just stuck down into the soft soil. The kind of soft soil that's prone to liquefaction in large earthquakes.


The city was already historically infamous for its artificially extended domain and the runaway development over that fragile ground. They erected the Millennium Tower on part of the 19th-century landfill and later garbage dumps that covered the original shoreline and beyond. Which includes the remains of abandoned ships in other areas. According to one map, the Salesforce Tower is being built just barely outside the man-made terrain, which might have facilitated it reaching bedrock or the design team's claim of such.

What Parts of San Francisco are Built on Land Fill?: [...] some of the neighborhoods of San Francisco were packed together out of sand and trash by generations of human hands. In 2006 -- 100 years after the great quake of 1906 -- a USGS representative stated that if an earthquake of the same magnitude hit the city that day, it would destroy nearly 40% of the city's buildings. The geologist also noted, “All the areas built on fill, such as the Bayfront, Marina district, financial district, and SoMa [south of Market], will be very vulnerable." [...] Mission Bay was a gulf of water surrounded by uninhabitable marsh, which many used as a dump, some in hopes of drying it out into viable real estate. It hit its tipping point after the catastrophic earthquake of 1906. The quake and subsequent fire had left the city’s infrastructure in ruin, and much of the wreckage went into the bay and surrounding marshland, until there was little enough bay and marshland that the region was suitable for development.

Early San Francisco History: [...] In 1849 more than 700 vessels carrying thousands of fortune-seekers came from around the world. San Francisco Bay instantly became one of the world’s greatest seaports [...] The land mass of San Francisco itself grew as the result of landfill dumped on the carcasses of hundreds of deserted ships whose crews abandoned them to search for gold. San Francisco’s border expanded a full 7 blocks east of the natural shoreline and four blocks north.

New Map Reveals Ships Buried Below San Francisco: [...] Every day thousands of passengers on underground streetcars in San Francisco pass through the hull of a 19th-century ship without knowing it. Likewise, thousands of pedestrians walk unawares over dozens of old ships buried beneath the streets of the city’s financial district. The vessels brought eager prospectors to San Francisco during the California Gold Rush, only to be mostly abandoned and later covered up by landfill as the city grew like crazy in the late 1800s.

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