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I sometimes get an idea and think "why haven't we done that?"... and perhaps we have. Venice is built on wooden stilts that are sunk into clay so tightly that

by buro9 3y ago

I sometimes get an idea and think "why haven't we done that?"... and perhaps we have. Venice is built on wooden stilts that are sunk into clay so tightly that the clay is essentially reinforced by the stilts and this allows them to support the stone structures on top. The clay also protects the wood from rot in a long-term way, which provides the longevity that Venetians obviously needed. Given that reinforcing clay with wood produces such qualities, why not produce taller organic structures where instead of concrete reinforced with rebar we have clay reinforced with wood? Is this something that has ever been tried above ground for tall buildings? (i.e. not driving stilts down, but lifting clay up and boxing it in before driving stilts into the box).

supermatt 3y ago
https://en.wikipedia.org/wiki/Wattle_and_daub https://en.wikipedia.org/wiki/Wattle_and_daub
- buro9 3y ago
  Not quite the same thing, and I meant for tall buildings. Venice is built entirely on a clay swamp, the wooden piles support the full weight of absolutely massive stone structures including St Marks Square, the tower and cathedral. https://sites.google.com/site/engineeringvenice/ https://sites.google.com/site/engineeringvenice/ Given that the relatively short wooden piles combined with clay produce such strength... what's stopping very tall wooden buildings existing?
  - deleted 3y ago
    [deleted]
  - masklinn 3y ago
    > what's stopping very tall wooden buildings existing? Buildings are generally valued for the space they create internally. Filling the inside with clay and piles is rather less convenient, you might as well put those in the ground. Which is exactly what we do.
  - supermatt 3y ago
    > the wooden piles support the full weight You kind of answered your own question. The clay is just supporting those piles, and the clay is supported by the substrate surrounding it, etc. Aside from the wattle and daub examples (of which I have seen 4-story examples) there are many large structures built with clay (in the form of bricks for load bearing walls, pillars, etc) and timber framing. Also, consider the density with which those piles are packed in venice - you would essentially end up with a building with no interior space - just piles.
    - jaclaz 3y ago
      Bricks are cooked clay. Venice substrate is wet clay.
      - supermatt 3y ago
        I don’t think that required clarification, but yes that is almost correct, in the sense that bricks don’t need to be cooked (the term used is “fired”) as they can also be left to dry naturally.
        jaclaz 3y ago
        Sure, though the fired ones are much more resistant than naturally dried ones. The note was more about the fact that clay in different states (wet/fired/dried) has very different properties and that the parent comment was ignoring that. BTW the way a foundation may work (wooden piles in a wet clay substrate) is very different from how a vertical structure (pillar/wall) or a horizontal one (beam/deck/slab) behaves. In the case of the foundation, the wooden piles distribute the vertical forces through lateral adherence (as opposed to applying it directly to the top surface) over all the inserted length, and in the particular case of the tight grid used in old Venice buildings, the wooden poles act also as containment, they are also called "friction piles".
masklinn 3y ago
> Is this something that has ever been tried above ground for tall buildings? (i.e. not driving stilts down, but lifting clay up and boxing it in before driving stilts into the box). I’m not sure it’d work for actually tall buildings as clay is quite heavy. But timbered and half-timbered commonly have wattle-and-daub, clay, or unfired brick infill (adobe, mudbrick). Though actual brick, stone, plaster, … are also common. As well as the infill changing as the building goes up (e.g. stone or brick on the low floors, with wattle or plaster on higher floors.

by buro9 3y ago

supermatt 3y ago

https://en.wikipedia.org/wiki/Wattle_and_daub https://en.wikipedia.org/wiki/Wattle_and_daub

buro9 3y ago
Not quite the same thing, and I meant for tall buildings. Venice is built entirely on a clay swamp, the wooden piles support the full weight of absolutely massive stone structures including St Marks Square, the tower and cathedral. https://sites.google.com/site/engineeringvenice/ https://sites.google.com/site/engineeringvenice/ Given that the relatively short wooden piles combined with clay produce such strength... what's stopping very tall wooden buildings existing?
- deleted 3y ago
  [deleted]
- masklinn 3y ago
  > what's stopping very tall wooden buildings existing? Buildings are generally valued for the space they create internally. Filling the inside with clay and piles is rather less convenient, you might as well put those in the ground. Which is exactly what we do.
- supermatt 3y ago
  > the wooden piles support the full weight You kind of answered your own question. The clay is just supporting those piles, and the clay is supported by the substrate surrounding it, etc. Aside from the wattle and daub examples (of which I have seen 4-story examples) there are many large structures built with clay (in the form of bricks for load bearing walls, pillars, etc) and timber framing. Also, consider the density with which those piles are packed in venice - you would essentially end up with a building with no interior space - just piles.
  - jaclaz 3y ago
    Bricks are cooked clay. Venice substrate is wet clay.
    - supermatt 3y ago
      I don’t think that required clarification, but yes that is almost correct, in the sense that bricks don’t need to be cooked (the term used is “fired”) as they can also be left to dry naturally.
      - jaclaz 3y ago
        Sure, though the fired ones are much more resistant than naturally dried ones. The note was more about the fact that clay in different states (wet/fired/dried) has very different properties and that the parent comment was ignoring that. BTW the way a foundation may work (wooden piles in a wet clay substrate) is very different from how a vertical structure (pillar/wall) or a horizontal one (beam/deck/slab) behaves. In the case of the foundation, the wooden piles distribute the vertical forces through lateral adherence (as opposed to applying it directly to the top surface) over all the inserted length, and in the particular case of the tight grid used in old Venice buildings, the wooden poles act also as containment, they are also called "friction piles".

masklinn 3y ago

> Is this something that has ever been tried above ground for tall buildings? (i.e. not driving stilts down, but lifting clay up and boxing it in before driving stilts into the box). I’m not sure it’d work for actually tall buildings as clay is quite heavy. But timbered and half-timbered commonly have wattle-and-daub, clay, or unfired brick infill (adobe, mudbrick). Though actual brick, stone, plaster, … are also common. As well as the infill changing as the building goes up (e.g. stone or brick on the low floors, with wattle or plaster on higher floors.