3 ms·

isn't building high-rises in SF precarious because the ground is soft, with inadequate bedrock? are there also concerns about aesthetics, if i understand?

barbazoo 4y ago
I would expect there to be a viable range of building heights (and building techniques) on the spectrum of single storey house to highrise.
jedberg 4y ago
From what I understand it's about the same as building in Tokyo. With modern technology and proper materials you can build a safe building. But the residential tower currently sinking into the ground indicates that either that isn't actually true or the rules aren't being enforced.
- mc32 4y ago
  Yeah, that one was a case of taking shortcuts. The bedrock was 200"[1] down but the studies they used said that wasn't necessary. So NOW they are taking steps to introduce new pilons that go all the way down to bedrock and will be braced to the current, faultily installed ones. [1] Not sure the exact depth, but whatever, they went like half way down to save on money.
- mullingitover 4y ago
  I think it's more likely that corners were cut with the Millennium Tower, or the engineers made an error of some kind. None of the other big buildings in SF are connected to the bedrock. None of the towers in LA have supports connected to the bedrock. Heck, the Burj Khalifa isn't connected to bedrock. They all use friction piles, and these can work fine if they're done properly.
  - aranchelk 4y ago
    > None of the other big buildings in SF are connected to the bedrock Absolutely not true. Salesforce Tower, Park Tower and 181 Fremont all being examples of tall buildings in the immediate vicinity that do go to bedrock. Whether or not friction piles are a good idea is another matter.
    - jjtheblunt 4y ago
      friction piles? (trying to look that up)
      - CydeWeys 4y ago
        The top page of Google search results for "friction pile" are all bang on.
        jjtheblunt 4y ago
        thank you
    - mullingitover 4y ago
      I stand corrected! I got my information from a soil scientist who was explaining that the bedrock wasn't anywhere close to the surface in SF and LA and misunderstood that to mean that none of the towers went all the way down. I stand by my claim that the Burj Khalifa isn't on bedrock, however.
lowdest 4y ago
In one notable case, it was decided to not bore all the way down to bedrock, resulting is a sinking building and many lawsuits. More commonly, someone complains that a planned building will cast a shadow, and after spending millions the builders are not allowed to proceed.
- grumple 4y ago
  The Millenium tower: https://www.theguardian.com/us-news/2022/jan/10/san-francisco-millennium-tower-sinking https://www.theguardian.com/us-news/2022/jan/10/san-francisc... https://www.imdb.com/title/tt8105988/ https://www.imdb.com/title/tt8105988/
mc32 4y ago
Here is someone who goes into detail about the Millennium Tower debacle: https://www.youtube.com/watch?v=ph9O9yJoeZY https://www.youtube.com/watch?v=ph9O9yJoeZY In short, shortcuts, or more charitably, miscalculations. They really thought they had enough margin to work with but obviously that wasn’t the case.
MisterBastahrd 4y ago
If that were true, there wouldn't be any building in the New Orleans area more than a couple stories high. Everything south of the lake is built on an alluvial delta.

barbazoo 4y ago

I would expect there to be a viable range of building heights (and building techniques) on the spectrum of single storey house to highrise.

jedberg 4y ago

From what I understand it's about the same as building in Tokyo. With modern technology and proper materials you can build a safe building. But the residential tower currently sinking into the ground indicates that either that isn't actually true or the rules aren't being enforced.

mc32 4y ago
Yeah, that one was a case of taking shortcuts. The bedrock was 200"[1] down but the studies they used said that wasn't necessary. So NOW they are taking steps to introduce new pilons that go all the way down to bedrock and will be braced to the current, faultily installed ones. [1] Not sure the exact depth, but whatever, they went like half way down to save on money.
mullingitover 4y ago
I think it's more likely that corners were cut with the Millennium Tower, or the engineers made an error of some kind. None of the other big buildings in SF are connected to the bedrock. None of the towers in LA have supports connected to the bedrock. Heck, the Burj Khalifa isn't connected to bedrock. They all use friction piles, and these can work fine if they're done properly.
- aranchelk 4y ago
  > None of the other big buildings in SF are connected to the bedrock Absolutely not true. Salesforce Tower, Park Tower and 181 Fremont all being examples of tall buildings in the immediate vicinity that do go to bedrock. Whether or not friction piles are a good idea is another matter.
  - jjtheblunt 4y ago
    friction piles? (trying to look that up)
    - CydeWeys 4y ago
      The top page of Google search results for "friction pile" are all bang on.
      - jjtheblunt 4y ago
        thank you
  - mullingitover 4y ago
    I stand corrected! I got my information from a soil scientist who was explaining that the bedrock wasn't anywhere close to the surface in SF and LA and misunderstood that to mean that none of the towers went all the way down. I stand by my claim that the Burj Khalifa isn't on bedrock, however.

lowdest 4y ago

In one notable case, it was decided to not bore all the way down to bedrock, resulting is a sinking building and many lawsuits. More commonly, someone complains that a planned building will cast a shadow, and after spending millions the builders are not allowed to proceed.

grumple 4y ago
The Millenium tower: https://www.theguardian.com/us-news/2022/jan/10/san-francisco-millennium-tower-sinking https://www.theguardian.com/us-news/2022/jan/10/san-francisc... https://www.imdb.com/title/tt8105988/ https://www.imdb.com/title/tt8105988/

mc32 4y ago

Here is someone who goes into detail about the Millennium Tower debacle: https://www.youtube.com/watch?v=ph9O9yJoeZY https://www.youtube.com/watch?v=ph9O9yJoeZY In short, shortcuts, or more charitably, miscalculations. They really thought they had enough margin to work with but obviously that wasn’t the case.

MisterBastahrd 4y ago

If that were true, there wouldn't be any building in the New Orleans area more than a couple stories high. Everything south of the lake is built on an alluvial delta.