I'm working on a project in which part of the story takes place on a planet that is mostly ocean. There is a small continent with some manufacturing and refinery structures, but the rest of the planet's inhabitable area is composed of "floorscrapers." These are like high-rise buildings, but they are tethered together by bridges and float on the ocean surface. Each floorscraper rises only a few feet out of the water, with the building's entire "height" submerged in the water. The buildings have buoys around their top surfaces, and ballasts in the bottom-most sections.

In my story, these floorscrapers are the occupied space on this planet, and contain housing, recreation areas, commercial areas -- everything except the potentially toxic and polluting industrial business that takes place on the natural ground. As it stands, the lower down in a floorscraper a person lives, the lower their status.

I'm not familiar with construction and the effects of water pressure -- what facts of architecture would be different say, 90 or 100 feet deep into the ocean, within a tower-like structure? The inhabitants of this planet are humans with typical abilities, with similar mechanical advances to our own.

UPDATE: Following some very insightful questions, I think it makes sense to have all manufacturing, public utilities, and "functional" aspects of the civilization exist on the land mass, with the floorscrapers serving as hybrid living and commercial areas. The planet is a popular trade port, and little-to-no agriculture or industry outside of raw materials processing takes place on the planet.

  • $\begingroup$ Welcome to Worldbuilding! We're glad you could join us! When you have a moment, please click here to learn more about our culture and take our tour. SE's Q&A model is one-specific-question/one-best-answer. I'd like to invite you to break this question into two posts - you'll get better answers. Most notably, because the question about lifestyle might be too primarily opinion-based to remain open, while the physics question should be pretty good. $\endgroup$ – JBH Jun 25 '19 at 18:03
  • $\begingroup$ And "what is the effect of X on society?" is always too broad. $\endgroup$ – L.Dutch - Reinstate Monica Jun 25 '19 at 18:07
  • $\begingroup$ Is the air in these structures contained or is it open to the atmosphere? $\endgroup$ – Bilbo Baggins Jun 25 '19 at 18:10
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    $\begingroup$ How do you suggest the food will be produced? Inside the buildings, or there will be some ocean farms outside? Also, "rises only a few feet out of the water" - is this a design requirement? There would be a few issues if we force buildings to sit that low. $\endgroup$ – Alexander Jun 25 '19 at 19:41
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    $\begingroup$ Hmmm. I disagree with broad. Wes isn't asking for construction specifications, only implications. 90% of the questions asked on this site could be thought of as too broad if you want to consider everything. I'd like to see more answers. I'm tempted even to post a bounty in a couple of days. Voting to leave open. $\endgroup$ – JBH Jun 25 '19 at 22:55

This may sound a little disappointing, but I think what you are looking for looks a lot like ships. (Possibly anchored, and with less powerful engines, if at all.)

  1. The problem with water is that pressure builds very quickly with depth. (Compare $10\,m$ of water to all of Earth atmosphere). That's why dams need to be thicker the deeper they go (see picture), and that's why it took two-hundred years (arguably) from the first real (military) submarines to get to the deepest point in the sea.

    enter image description here source: wikipedia/user: Captain

    So building "deep" would probably be more expensive than it is to build "tall" on land. Besides, a sea world means plenty of (land?) area to build on.

  2. Anchoring. Though the name floorscraper could suggest touching the seafloor (or even being built on it,) I'd advice against touching it directly, just like ships. (See a couple of reasons below.) Of course you want to have a more or less fixed access to land, but flexible anchors and bridges should be enough.

  3. Currents and tides are —coeteris paribus— a lot stronger than wind (because water is denser than air, which means more kinetic energy.) If you have ever seen the foundations for docks and can compare them to those for a similar structure on land, you'll get what I say. If you want your floorscrapers to be fixed to the seafloor, it means a lot more problems. The easiest solution is to let go, and restricting the movement through either anchorage and/or engines.

  4. Height above sea level. You need some to stay afloat, and it's cheaper to build. Not too much, to keep the building stable, not too little, to keep it floating. Even if buildings are submarine-like (in the sense that water does not enter easily over the top), a good buoyancy gives time in case of an emergency.


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