7 ms·
Having made a few dry stone walls I can attest to the merit of this achievement. Judging where rocks are to be placed, and in what orientation is a zen art. An
by Daub 3y ago
Having made a few dry stone walls I can attest to the merit of this achievement. Judging where rocks are to be placed, and in what orientation is a zen art.
Anecdotally... I once tried to get wild flowers to grow on a stone wall. Every year we would seed the wall, only for the seeds to fall out or be eaten by birds. On inspiration, my boss filled a few shotgun cartridges up with seeds and fired them at the wall. Perfect result! The following year it was covered in flowers.
- 93po 3y agoNow this is gardening I can get behind
- chaboud 3y agoWell please don’t stand in front of it…
- schiffern 3y agoNot only is this a technical marvel, but it has potential construction physics implications. In simple terms, currently we expend energy to fragment rock, and then we expend additional energy (as concrete) to glue it back together. We do all this to re-arrange rocks into a shape (and strength) we want, and most importantly to do it cheap. Suddenly, an alternative just got a lot cheaper. Clearly this isn't fully baked yet (and it's hardly a drop-in replacement for reinforced/pretensioned/cantilevered/etc) but for things like heavy infrastructure and civil engineering this might offer a way to achieve fundamental thermodynamic improvements. Excited to see where this technology goes.
- samtho 3y agoThe problem with dry stone construction is that you cannot determine the performance characteristics required for, say, a building foundation. Not all boulders are created equal, but a professional concrete pour, mixed and installed to the manufacturer’s specification is going to have a guaranteed maximum strength- something random boulders will not have. What we can do is create our own concrete mix using Portland cement (the “glue”) and locally sourced materials to bulk it up such as gravel, aggregates, sand, etc.
- schiffern 3y agoSo the question becomes, how do existing concrete manufacturers determine whether locally sourced materials ("random rocks") are suitable? In traditional dry stone construction, strength of each rock is determined by sound and by sight. It seems crazy, but nowadays this should be feasible with a neural net. If you want to get fancy (or achieve high reliability) add ultrasound in the grippers or other sensor modalities. Or... you target a market other than building foundations? :) I suspect different groups could pursue both paths.
- beambot 3y ago> how do existing concrete manufacturers determine whether locally sourced materials ("random rocks") are suitable? They test individual samples from each pour on a calibrated press. For large buildings and critical pours, they'll keep & test multiple samples that undergo accelerated aging to make sure they're up to spec for the anticipated lifetime of the building (or until the concrete fully stabilizes over a few months / years).
- diroussel 3y agoSo could catagorization of local stone based on acoustic and visual indicators, combined with random sampling and strength testing provide the assurance needed that a wall will have the required structural properties?
- crotchfire 3y agoThe point is that the concrete manufacturers pulverize and homogenize the aggregate. This makes random sampling acceptable. If you haven't pulverized and mixed the inputs, a random sample is merely a random sample. It isn't meaningful unless it comes from a high-entropy source.
- diroussel 3y agoSo are you saying we couldn’t estimate the structural properties of autonomous built dry walls from local stone? Or that the error bars would be unacceptably large? Or just that this approach would only work with certain stone in certain locations?
- ReptileMan 3y agoTensile strength will be a problem. Compression will be solved eventually, the tetris part also. But if there are to be tensile or twisting loads - there will be trouble.
- londons_explore 3y agoAdd steel/fiberglass tension rods and you can trade off compressive for tensile strength.
- klyrs 3y agoSo... reinforced concrete.
- rewmie 3y ago> Not only is this a technical marvel, but it has potential construction physics implications. I don't think this is true. Gabion walls are already widely used, particularly in geotechnical structures, and masonry structures have been around for literally thousands of years. The reason modern building technologies such as concrete/steel/composite structures replaced these techniques is that they are far safer, easier to maintain, far more space-efficient and and impose far fewer architectural constraints. Automating this process helps drive down the cost, but cost is one of many factors and not a critical one. > Suddenly, an alternative just got a lot cheaper. Not really. This article just showcases a way to automate the construction of a particular wall type. This by no means implies these walls are now competitive. Other than aesthetics, I don't see how it's possible to even conceive standard techniques such as gabion walls being replaced by dry-stone walls. The cost of building a gabion wall is literally the cost of a metal mesh and filling it with rocks. Gabion walls are even used by armed forces as rapid-deployment defensive walls in the form of Hesco bastions. https://en.wikipedia.org/wiki/Hesco_bastion https://en.wikipedia.org/wiki/Hesco_bastion
- DigiDigiorno 3y agoI'm surprised the seeds would survive the heat and pressure of a shotgun cartridge blast that contained enough gun powder to embed them in a wall
- adammarples 3y agoIt sounds like judging where rocks are to be placed is a simple optimization algorithm
- Obscurity4340 3y agoDidn't they do that in The Grinch?
- ascorbic 3y agoFor future walls, try a Cornish hedge. Despite the name, these are actually dry stone walls with an earth core. Mature ones are normally covered in wildflowers. Here's how they're made. http://www.cornishhedges.co.uk/PDF/building.pdf http://www.cornishhedges.co.uk/PDF/building.pdf
- lapsed_pacifist 3y agoThis isn't really a proper wall though, it's a single thickness stack. I don't think it could handle any lateral force at all without toppling. If this machine could build a double skin wall with batter, wall heads, and hearting throughout the center, I'd be really impressed!
- londons_explore 3y agoI suspect all those things are just fairly minor software changes...
- Matumio 3y agoThis is the way you use a gun. What a flowery blossoming place this world would be. Reminds me of https://en.wikipedia.org/wiki/Swords_to_ploughshares https://en.wikipedia.org/wiki/Swords_to_ploughshares
- m463 3y ago> my boss filled a few shotgun cartridges up with seeds and fired them at the wall. A friend of mind had a hill in his yard, and hired a guy that knew the local seed mix to hydroseed it. It went well. https://en.wikipedia.org/wiki/Hydroseeding https://en.wikipedia.org/wiki/Hydroseeding Can't figure a good word would be for what your boss did. It's not quite pyroseeding...