3 ms·

This is good point. If you are willing to go deep enough, can you build anywhere?

ocdtrekkie 5y ago
Technically, probably yes, but the math could get ridiculous. Essentially you want to go into solid ground, and if you're in the ocean, solid ground might be miles below sea level. And reclaimed land doesn't change that. Also, if the material higher up shifts, your supports need to be able to survive the ground shifting around it, which means you need not just depth, but girth.
- rsj_hn 5y ago
  It would be very unusual for a city's headlands to be literally miles above solid ground, especially for the carribean, which is extremely shallow (hence the hurricanes). Take a look at the Florida keys, where you can find bedrock after a couple of meters. You can even go out a mile into the sea and hit bedrock after 6-8 meters: https://pubs.usgs.gov/pp/2007/1751/professional-paper/figures/bedrock-surface.html https://pubs.usgs.gov/pp/2007/1751/professional-paper/figure...
  - Someone 5y ago
    I wouldn’t know whether it’s very unusual, but https://blogs.egu.eu/divisions/ts/2019/06/17/in-search-of-the-oldest-rocks-of-a-muddy-country/ https://blogs.egu.eu/divisions/ts/2019/06/17/in-search-of-th...: “Digging down in Amsterdam, it takes about 1000 meters until we find the first solid rock”. There are more or less solid sand layers at much lower depths, though. That’s what buildings stand on. It would surprise me if other cities in the west of the Netherlands were different.
  - pdoege 5y ago
    Keep in mind that bedrock in this context is limestone and oolite. This rock is not an ideal foundation material. http://www.mgs.md.gov/geology/geohazards/engineering_problems_in_karst.html http://www.mgs.md.gov/geology/geohazards/engineering_problem... Harder rock is deep, around 1,300m. (4,000ft). https://ufdc.ufl.edu/UF00000245/00001/20x https://ufdc.ufl.edu/UF00000245/00001/20x
  - jjav 5y ago
    > especially for the carribean, which is extremely shallow (hence the hurricanes) The Caribbean is nowhere near shallow, take a look at a marine chart or just the seafloor topography on google maps. The Caribbean is thousands (often over 10K) of feet deep in most areas. Also, this has nothing to do with hurricanes, which originate off the west coast of Africa. Also, the Florida Keys are not in the Caribbean.
- wumpus 5y ago
  There are many points south of SF against the Bay where the solid ground is down far enough that they instead drive piles until they find enough resistance. Oracle's HQ is still standing. But the (East) Palo Alto 4 Seasons Hotel, whoops.
  - djmips 5y ago
    Although it was reported that it had experienced more than expected settling, didn't the 4 Seasons open? Are there still problems?
    - wumpus 5y ago
      I vaguely remember that they went back and drove more piles, somehow, until the building was stable that the exterior glass facade no longer shattered on a regular basis. However they did the work, it wasn't visible from the outside.

Technically, probably yes, but the math could get ridiculous. Essentially you want to go into solid ground, and if you're in the ocean, solid ground might be miles below sea level. And reclaimed land doesn't change that. Also, if the material higher up shifts, your supports need to be able to survive the ground shifting around it, which means you need not just depth, but girth.

rsj_hn 5y ago
It would be very unusual for a city's headlands to be literally miles above solid ground, especially for the carribean, which is extremely shallow (hence the hurricanes). Take a look at the Florida keys, where you can find bedrock after a couple of meters. You can even go out a mile into the sea and hit bedrock after 6-8 meters: https://pubs.usgs.gov/pp/2007/1751/professional-paper/figures/bedrock-surface.html https://pubs.usgs.gov/pp/2007/1751/professional-paper/figure...
- Someone 5y ago
  I wouldn’t know whether it’s very unusual, but https://blogs.egu.eu/divisions/ts/2019/06/17/in-search-of-the-oldest-rocks-of-a-muddy-country/ https://blogs.egu.eu/divisions/ts/2019/06/17/in-search-of-th...: “Digging down in Amsterdam, it takes about 1000 meters until we find the first solid rock”. There are more or less solid sand layers at much lower depths, though. That’s what buildings stand on. It would surprise me if other cities in the west of the Netherlands were different.
- pdoege 5y ago
  Keep in mind that bedrock in this context is limestone and oolite. This rock is not an ideal foundation material. http://www.mgs.md.gov/geology/geohazards/engineering_problems_in_karst.html http://www.mgs.md.gov/geology/geohazards/engineering_problem... Harder rock is deep, around 1,300m. (4,000ft). https://ufdc.ufl.edu/UF00000245/00001/20x https://ufdc.ufl.edu/UF00000245/00001/20x
- jjav 5y ago
  > especially for the carribean, which is extremely shallow (hence the hurricanes) The Caribbean is nowhere near shallow, take a look at a marine chart or just the seafloor topography on google maps. The Caribbean is thousands (often over 10K) of feet deep in most areas. Also, this has nothing to do with hurricanes, which originate off the west coast of Africa. Also, the Florida Keys are not in the Caribbean.
wumpus 5y ago
There are many points south of SF against the Bay where the solid ground is down far enough that they instead drive piles until they find enough resistance. Oracle's HQ is still standing. But the (East) Palo Alto 4 Seasons Hotel, whoops.
- djmips 5y ago
  Although it was reported that it had experienced more than expected settling, didn't the 4 Seasons open? Are there still problems?
  - wumpus 5y ago
    I vaguely remember that they went back and drove more piles, somehow, until the building was stable that the exterior glass facade no longer shattered on a regular basis. However they did the work, it wasn't visible from the outside.