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A circular 3D-printed concrete bridge
- IshKebab 3y agoNeat design. More than one tiny photo would have been nice! I guess the difficulty with 3D printed concrete is adding reinforcement, and it sounds from this like they haven't solved that, they've just used a geometry that is entirely in compression?
- chrisshroba 3y agoHere's a few more! https://www.holcim.com/who-we-are/our-stories/striatus-bridge https://www.holcim.com/who-we-are/our-stories/striatus-bridg...
- i_am_jl 3y agoThat's Striatus, a predecessor to this construction called Phoenix. https://www.holcim.com/who-we-are/our-stories/phoenix-bridge https://www.holcim.com/who-we-are/our-stories/phoenix-bridge
- htk 3y agoLove the mix of organic and industrial design.
- qwertox 3y agoThis would be a better link: https://www.designboom.com/technology/holcim-3d-prints-phoenix-reinforcement-free-concrete-bridge-12-14-2023/ https://www.designboom.com/technology/holcim-3d-prints-phoen... The components were printed off-site and then assembled on-site. While I like the structure a lot, I think it could benefit safety-wise from a proper floor layer, as the small ridges could cause someone to stumble, specially running kids.
- chrisweekly 3y agoYes! Lots of pictures vs just one.
- rossdavidh 3y agoI wonder, if there were no small ridges, how the water would behave during rain. Do the small ridges break it up so that it's not a complete sheet of easy-to-slip-on-it water? (or ice) (well, I don't know that Phoenix has that much ice) IANAA (I am not an architect)
- calamari4065 3y agoThe ridges would give better grip when wet, but the bridge would get covered in ice much easier
- toast0 3y agoPhoenix is the name of the bridge, not where it has been installed. Also not an architect, but I suspect this wouldn't get installed in Phoenix as shown, I don't think it meets US ADA accessibility requirements: the slope looks a bit high, there's no level landing at the top, and the concave surface of the ramp seems problematic as well.
- wongarsu 3y agoProvided there are enough other crossings of those paths, does it have to meet ADA requirements? It's not really providing any function besides connecting paths, and if the same function is also provided a stone's throw away this structure isn't a big bother. Not that we should dot our landscape with such things
- toast0 3y agoFor new construction, the standard is roughly "In new construction, all areas must be fully accessible, including multiple spaces of the same type, unless otherwise specified." [1] I don't think a useless bridge on a roughly flat site (as depicted in the installation images) qualifies for exceptions, IMHO. There's no reason it would be impractical to make it accessible, so it must be made accessible. [1] https://www.access-board.gov/ada/guides/chapter-2-new-construction/ https://www.access-board.gov/ada/guides/chapter-2-new-constr...
- chrisweekly 3y agoLove that it's using recycled materials.
- MeteorMarc 3y agoThat is what the title means with circular.
- bradly 3y agoAccording to the article "circular" references the way the concrete blocks fit together like a mansonry arch. This allows for much less reinforcement that way a typical concrete bridge requires.
- i_am_jl 3y agoThis is very cool, and gorgeous, but being the pedant I am I feel I need to ask, "Is it really a bridge if it doesn't cross over an obstacle?"
- jawns 3y agoI understand that this is more of a proof of concept than a bridge built to solve a practical problem ... but it feels like this structure was engineered NOT to solve a problem. Normally bridges allow you to cross over something that you could not otherwise easily cross, such as a stream, a gully, or a competing transport path. But this bridge basically sits over some flat paths that are easy to traverse as-is, and it makes them harder to traverse, because now you need to go up and down the bridge. Indeed, because of the bumpiness of the structure, I would not be surprised if it is inaccessible for wheelchairs and bicycles, where a flat path would have been adequate. So as a technical feat, I guess it achieves its desired purpose, but it has negative practical value.
- bradly 3y ago> but it feels like this structure was engineered NOT to solve a problem. The problem they are trying to solve is how to quickly and efficiently build bridges. They built something to facilitate learning how to do that in the most practical means for them.
- shmichael 3y agoCan't wait to read your review of the Wright Brothers' first (utterly "useless" and dangerous) flight. :)
- idiotsecant 3y agoBridges are a somewhat solved problem at this point. Novelty for the sake of novelty when the end product is worse is not good engineering.
- Aurornis 3y agoThe bridge is just a demo piece for the manufacturing technology. I can’t believe this has to be said, but they’re not trying to invent bridges that go over flat land. It’s a demo piece. This is like when someone gets a 3D printer and prints a 3D Benchy boat. Making toy boats is a solved problem, but that’s not the point of the 3D printer.
- dtgriscom 3y agoInteresting things from the assembly video: - The printer prints variable-thickness layers in order to have the joint faces be non-parallel - There are no additional beams inside; it's just the concrete pieces - They make a wooden form to support it while being assembled, and then remove it when the structure is complete - It's unclear what the black joining material is, and whether it's adhesive
- sbierwagen 3y agoBetween the wooden framework and the crane needed to lift the segments into position, it just sounds like a more complicated way to do precast construction. They note that 3d printing means the segments can have voids in them, but Spancrete has been selling hollowcore concrete panels for 70 years.
- Aurornis 3y ago> it just sounds like a more complicated way to do precast construction. Precast requires a mold. Molds are expensive. If someone was making 100 or 1000 identical bridges of the same dimensions, precast would be the way to go. That’s missing the point of this technology, which would allow one-off designs to be produced without molds.
- sbierwagen 3y agoHow often are one-off designs actually required? Quirky, unique concrete structures seem like a market limited to the high end only.
- IshKebab 3y agoBridges are almost always one-offs aren't they? (If you exclude things like motorway crossing bridges, but that's clearly not the target here.)
- jdblair 3y agoI can't tell if this is circular because of the shape, or circular as in "circular economics."
- pcl 3y agoLooks like it's circular as in "circular economics". But that's a pretty tenuous claim -- it also looks like there is no re-use, which seems like it should be an important part of the concept. Presumably they're just latching onto the buzzword to get some grant funding or qualify for some project requirements or something?
- ddkto 3y agoCircular economics: The Phoenix bridge: Improving circularity of 3D-concrete-printed unreinforced masonry structures - https://block.arch.ethz.ch/brg/publications/1310 https://block.arch.ethz.ch/brg/publications/1310 (Edit : link format)
- KevinMS 3y agoI'm a 3D printing enthusiast, but I have to admit I don't see any problem this is actually solving.
- strainer 3y agoIt enables more precise and complex concrete structures, reducing the amounts of concrete required.
- KevinMS 3y agoagain, there is no problem this is solving
- recursive 3y ago"Too much concrete is being used".
- KevinMS 3y agoyou really think a little more concrete is a problem? its the most abundant construction material in the world.
- recursive 3y agoMe personally? I don't have an opinion, but I guess concrete production represents 4-8% of global co2 emissions. Not sure where "little" is coming from. Concrete is ubiquitous. If a more resource-efficient process is available, it might be often applicable. https://www.theguardian.com/cities/2019/feb/25/concrete-the-most-destructive-material-on-earth https://www.theguardian.com/cities/2019/feb/25/concrete-the-...
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- beebeepka 3y ago[flagged]
- tedunangst 3y ago> Phoenix stands solely through compression without reinforcement, with blocks that can be easily disassembled and recycled. Would love to see some time lapse. How does it stay up while you're assembling it?
- kwhitefoot 3y agoTraditionally you erect scaffolding to support it until the keystone is in place
- the__alchemist 3y agoI'm almost through playing The Talos Principle 2. It has an element I so adore in Sci-Fi: The "Could we do this?" thought. And... in this particular case, I am quite interested in automatically and cheaply creating concrete structures of semi-arbitrary designs. (And, I concur: GO to qwertox's link; not the one in the article) The segmented construction of this design is very interesting; build the pieces separately using a smaller print area, then assemble using a crane etc. The most surprising aspect was lack of rebar.
- shermantanktop 3y agoThe problem with truly “semi-arbitrary” designs is not the ability to build them cheaply or easily. It’s the ability to ensure that they are safe, sturdy, durable and low-impact. Dr. Seuss can draw crazy bridges with a stroke of the pen…while I love the visual interest and creativity they represent, practical structures tend to look “normal” because of practical reasons. Yes, there are zoning codes, traditions, regulations, etc., but that’s not why we don’t have 30 foot concrete arches over suburban homes. I do think this could provide cheaper ways to create small variations in design, and those small variations are crucial to making a built landscape look human.
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- GeoAtreides 3y agoAll these comments about bridges being a "solved problem" or having "negative practical value" or how it doesn't cross anything... It's a tech proof of concept. That's what it is. It says what they're testing right there in the article: - improvements in the robustness of the digital design tools, - closer alignment with the numerous structural design and circularity-related improvements, - tighter integration with robotic concrete printing parameters - extensive calibration to improve efficiency of production of almost double the number of blocks in less printing time - after two years and in its second iteration, Phoenix adds a largely reduced carbon footprint and permanence according to building codes along with many other further improvements So, to put it in tech terms, this is the second iteration of a prototype technology, that is now safe enough to be released as an alpha build (in the form of a small public work of art in a kids' playground). They will now iterate again and in the future try for something bigger, presumably. Not everything can be on a grand scale from the get go, more so unproved new infrastructure technology. Like, you wouldn't have used Docker ver 0.1 alpha in production, right?
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- kazinator 3y ago> Circular by design, Phoenix stands solely through compression without reinforcement, with blocks that can be easily disassembled and recycled. Wow, if the Romans had known about this, they could have had a much better way to build arches than all that rebar.
- GeoAtreides 3y agoFunny enough, the Romans didn't know about this and also had a better way to build arches without rebar, as they didn't use rebar at all
- jqpabc123 3y agoLikely only viable for novelty structures carrying light loads. If you look at this from a strict engineering perspective, a set of steps resting on the hill in the background could have achieved the same result at a fraction of the cost.
- IshKebab 3y agoWhy light loads? Concrete arches should be able to carry extremely heavy loads. I don't understand what you mean about a set of steps achieving the same result. That wouldn't be a bridge.
- usrusr 3y agoDepends on how close "concrete ink" made from random torn down buildings comes to the performance characteristics of concrete from well known sources that is cast in place. Even that has a super wide range of performance characteristics. Chances are the printed blocks are much weaker, perhaps like particle board vs proper wood.
- jqpabc123 3y agoConcrete arches should be able to carry extremely heavy loads. Monolithic concrete structures, yes. Concrete pieced together, not so sure. That wouldn't be a bridge. No, it wouldn't. In this particular cases, there is nothing being bridged. The only place this "bridge" goes is up a small incline in the background.
- usrusr 3y agoTraditional masonry, but instead of subtractively carving precision stone shapes from larger units of source material they create custom shapes in an additive process. Given the reactions here I'm not sure that a "bright to nowhere" was a good idea as a demonstration project, but I guess their target audience are architecture professionals who will easily see the process begins the demo. I wonder how much of the recycled material really is concrete: the writing seems to carefully tread around any specifics, trying to distract with absolute quantities. Could it be that this "concrete ink" is basically a composite of recycled plastic and ground concrete? I'd imagine that this could achieve limestone-like performance while pretend-solving disposal.
- Valgrim 3y agoThe structure is purely a demonstration. It appears to be built on the company's ground, so there's a lot less red tape and they can show it off to potential buyers easily. Also the area is flat and has no natural obstacles like a river, with a low population density (it's actually near Lyon's main airport) so it's less likely that vandalism or accidents could cause damage to the structure.
- usrusr 3y agoAnd the nonsensical "organic" bridge shape actually does serve a function, demonstrating how different the elements are shaped. If expect trained architects to understand without much explanation.
- ribs 3y agoI like this quote: “Concrete is an artificial stone, and like stone, it does not want to be a straight beam, it wants to be a masonry arch.”
- simonebrunozzi 3y agoI saw this bridge in person ~2 years ago in Venice, during the 2021 architecture Biennale. It is not as impressive as it looks like.