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Note: this question uses a third-party world and species to illustrate the point of, and help lay out the thought process leading to, the question, but it is not in any way about them; therefore, this question is not off-topic.

So I was rereading There Is No Antimemetics Division, and this tidbit1 stuck in my mind:

[...] It's a phenomenon Dr. Bartholomew Hughes and his team spent years figuring out how to replicate. They've got it, now. They can synthesise C. gigantes bone, extruding it in prefabricated pieces from steel grids. They can bolt the plates together to make hermetically sealed boxes. [...]

[There Is No Antimemetics Division, chapter "Wild Light"; emphasis added.]

Sometime later on, I was idly musing about the structure and properties of bone, and those couple sentences about building things out of engineered bone came to mind again. Cortical bone, after all, is quite strong, considerably outperforming concrete in both compressive (100-170 MPa [with about half of that variation coming from differences between male and female bone], whereas concrete tops out at 70 MPa) and tensile strength (yield strength 100-120 MPa and ultimate strength around 135; while this isn't great [even infamously-weak-in-tension cast iron outperforms bone here], it's still much better than concrete's low-single-digits-of-MPa tensile strength) while also being somewhat lighter (bone: 1.6-2 g/cm3; concrete: 2.2-2.5 g/cm3).

How useful would engineered bone (human or animal) - whether grown as a single monolithic framework, as separate structural members to be joined to each other during construction, or as many individual bone bricks and slabs to be stacked together - be as a load-bearing structural material (either unreinforced or grown onto a reinforcing metal framework for extra tensile strength)? (Assume that the technology is available to grow arbitrarily-shaped pieces of cortical bone on an industrial scale, and to tailor the bone's structure to resist loads along whatever directions its position in a structure requires.)

(Not a dupe of this question, which is about the utility of large numbers of animal bones in their naturally-occurring forms as building material, rather than bone specifically grown as the structural framework of a structure.)

1: (Among many others.)

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  • $\begingroup$ Hi. I'm getting "C. gigantes" as referring to a Puerto-Rican basketball team. Not to worry, I can imagine what you might mean. Could you tell us about your worldbuilding project, what you intend to use it for, else the question will likely get closed as about a third-party world and off-topic. $\endgroup$ Commented yesterday
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    $\begingroup$ Cryptomorpha gigantes referenced in the wiki you link to would seem to refer to a real-life beetle, i.e. no bone. Perhaps edit that bit out altogether and just state the worldbuilding question. $\endgroup$ Commented yesterday
  • $\begingroup$ @Escapeddentalpatient.: The mentioned passage was merely my inspiration for asking the question; my question is about the structural utility of engineered bone generally. $\endgroup$ Commented yesterday
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    $\begingroup$ You've not told us about your project, just asked an open-ended question: "How useful would engineered bone (human or animal) - whether grown as a single monolithic framework, as separate structural members to be joined to each other during construction, or as many individual bone bricks and slabs to be stacked together - be as a structural material ". Can you narrow it down, and add details about your individual use-case else it's going to be way too broad. $\endgroup$ Commented yesterday
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    $\begingroup$ Dang nabit. I really don't want to vote to close your question, but open-ended questions are specifically prohibited in the help center. How useful is iron? sand? a lollipop? Everything you can possibly imagine is useful for something. What metric will you use to judge a best answer? What kind of answer are you even looking for? Remember the tour, we are not a discussion forum. Can I build a treehouse out of bone? Yes! A skyscraper? probably not. When are we supposed to stop answering? Argh! VTC:Needs More Focus. $\endgroup$ Commented yesterday

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They would be rather useful.

Bones have been already used by our ancestors as structural material for building shelters, see here an example

picture of a hut made with mammoth bones

The discovery of a prehistoric hut made from mammoth bones in Mezherich, Ukraine, remains one of the most significant archaeological finds of the 20th century. This site, dating back approximately 15,000 years, offers a rare glimpse into the lives of our ancient ancestors and their remarkable ingenuity in building early shelters. These huts, found in the village of Mezherich, provide not only evidence of early architecture but also deep insights into the culture, social organization, and survival strategies of prehistoric human communities.

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    $\begingroup$ Not to say these definitely aren't huts, much less that bones couldn't be used as such, but there has been recent disagreement about interpreting the mammoth bone structures as dwellings. There's various reasons, but two that stood out: 1) Many (most?) of them don't feature a hearth or other heat source, and 2) Often the bones are arranged in patterns, and with small items carefully interspersed between large bones, that would be very unlikely to happen if these are collapsed dwellings. Stefan Milo did an interesting video on it last year $\endgroup$ Commented 15 hours ago
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On the given data, it would seem that bone could replace brick or stone provided you could get enough material that you can trust. Wood is still one of the best materials for making aircraft, but it warps and rots, and has knotholes. If you had a supply of bone blocks you could probably build anything that you could build out of stone. However, a good stone quarry may have layers tens or hundreds of metres thick of solid stone that can be sawn into blocks, ready to bear loads. Your bone supply would have to equal that at the same price. The real argument against bone is probably an economic one.

However, bone is not done yet. Consider living bone. This has internal voids bridged by a web of slender columns. These columns are continuously being broken and regrown. This is a dynamic equilibrium which makes the bones exactly as strong as they need to be in the right places. If we are old, do not exercise, or we are weightless, our bones become weaker.

Leonardo da Vinci proposed a bridge over the Golden Horn for Sultan Bayezid II. This would have been made from stone with a span of 220 metres. This design was considered unsafe back then, in part because the supporting columns looked too thin. The design would be considered unsafe these days because Istanbul lies on the boundary of the Eurasian and Anatolian tectonic plates, and the bridge would be on the gap between the two.

Leonardo's arch had large internal voids to give it a stiff but light structure. This is somewhat bone-like. Suppose we had a bridge with a bone-like structure that could repair itself like bone does. If the tectonic plates move slightly, some internal struts would carry extra stress, while others might carry less. If the bridge could transfer the strength to where it is now needed.

A living bridge is a fun idea. Gaudi would have loved it, but I don't think this is practical. But it may be sensible to have a bridge with voids spanned by struts that are continuously adjusted and remodelled as bone is. Leonardo could have done this with stone, but this would mean wedging open a gap to insert a fresh course of blocks. If you can make a bone strut stronger and thicker in situ, we may be onto something.

Bone only wins if it does something that stone can't. You could have stone struts with piston-like voids filled with sand. If you inspect it and the sand level has dropped, the ends of the strut are moving apart and it is taking less stress. We can put in a screw-jack to move the ends apart, and add more sand or an extra course of blocks if there is a lot of movement. We could remove sand from the neighbours if they may be over-stressed. This would be enough for routine maintenance, and we could build whole new struts as necessary.

IMHO: bone has some advantage over stone as a building material, but not enough to open up new possible structures.

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The collagen that gives bones their strength decomposes

The mineral structure of bones is, by itself extremely fragile and brittle - old bones crumble. It’s the collagen in the bones that gives them strength and, unfortunately for long term structures, this decomposes. That’s why fossils are rare and we don’t spend our lives walking on the skeletons of those who went before us.

Now, if you could make your structures out of living bones …

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A grown and evolutionary optimized material to withstand a pressure in a downwards direction and reused as a building material?
Have you considered to search for what you can do with wood?
Wood falls into the same category and is heavily used to build houses, you can even build complete skyscrappers out of wood, see the Mjøstårnet with a height of 85.4 m (280 ft).

A quick search revealed that bone can withstand higher pressures than wood (almost 3 times). I found no relyable sources about the comparison of a stability-to-weight ratio, but I (and google AI) expect bone to have a better ratio than wood.

So yes, if you need stable but also light materials, then bones would be a great material to use, especially if you can grow it however you need it.

For reference: Trees are cut into pieces and often layed down horizontally. That is definitely not the evolutionary intended usage of the tree's wood (trees evolved to stand upright). I am pretty sure this is not the best possible way to withstand big forces, but still this is very stable.
Now with that in mind, consider that you should get even better results when you could grow it in the shape it is really needed. If you can do the same with bones it should be even better.

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You could use it for small, independent, specific structures, but for large spans you would still need concrete and steel

Bones have evolved specifically for being strong over small distances, using calcium phosphate and organic material to create an ideal balance of effective compression and tensile strength in a complex closed cell structure.

However, biological evolution doesn't really need to support live and dynamic building loads, deal with earthquake or fire ratings, nor incorporate economics, logistics and practicality in bones. You need to deal with all these issues regarding an ideal support structure for buildings:

  • Heavy Loads - if you think of all items in a building (equipment, plant rooms, A/C units, people, glazing) these all add up in weight and would likely exceed any tolerance bones would have to compression - not just over one floor but multiple floors. Steel and concrete on the other hand are ideal materials for compression. Not only 'dead' loads (weight of building itself) but 'live' loads (weight of wind, people, furniture)
  • Spanning - steel is ideal to span long distances with minimal increase in profile. I would imagine bones would have a large increase in profile depth as you extend past 1m distances. There would be a certain maximum spanning distance before the cross-profile gets so large it becomes impractical.
  • Connections - Unfortunately I cannot think of an ideal way to connect bones to other building elements (such as connections to foundations, roof structures, or incorporate glazing and lintels)
  • Fire - all structures require fire-rating (in the modern world) to withstand heat. Although bones are fairly resistive, concrete still holds the advantage.
  • Economics - growing bone I could imagine would take a long time, and also would be difficult to assess grade - unlike steel and concrete. For example each piece of structural bone member would need to be grown specifically for its purpose due to the honeycomb nature of bone, but in todays industrial world a certain profile of steel can be any length and fit for multiple purposes - assisting logistics and practicality.

So I would imagine bone can be used in small buildings up to perhaps 3m, single storey and with no expectations of modern building usage. Beyond that, you would need to use more massed produced, higher strength generic materials.

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  • $\begingroup$ "Steel and concrete on the other hand are ideal materials for compression." Concrete is weaker than bone in compression (as I pointed out in the question), so, if concrete's an ideal material in this regard, bone must be even more ideal (by about a factor of 2). "Connections - Unfortunately I cannot think of an ideal way to connect bones to other building elements (such as connections to foundations, roof structures, or incorporate glazing and lintels)" Presumably the same ways concrete (or masonry in general) structural members're connected to other building elements. $\endgroup$ Commented yesterday
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    $\begingroup$ @Vikki Compressive strength is not a simple number - it depends on direction/anisotropy, material fatigue, density and geometry. Also loads come in broad and point-form, constant and dynamic. A concrete slab-on-ground spreads load very effectively on footings - and can take hundreds of tonnes load, a concrete reinforced beam is readily used in bridges, with different actions in the beam operating differently, omnidirectional, in both live and dead load fashion. Bone is set-up specifically, with few types of action catered for. One direction of load, one type of force. It is precisely designed. $\endgroup$ Commented yesterday
  • $\begingroup$ Joining two pieces of steel together (for instance, Steel Roof purlin to Steel Column) can be rigid with a joining plate, and penetrating bolts. Or more commonly a welded connection. Joining bones is completely different - penetrating bone would likely affect the honeycomb structure, with unable to weld. Another example: Fixing roof sheets to steel you can use self-tapping screws to tap into flange of steel purlin, but for bone I'm pretty sure a self tapping roofing screw would shatter it. Bone is not solid - it is hollow and once broken I'm sure it's structural strength is greatly reduced. $\endgroup$ Commented yesterday
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    $\begingroup$ "Bone is set-up specifically, with few types of action catered for. One direction of load, one type of force." Natural bone, yes, because natural bone is generally loaded mostly in one direction, and, consequently, grows to resist force in that one direction. Engineered bone, on the other hand, could be grown to resist and carry loads in all the directions its particular place in a building's skeleton calls for it to carry loads in - which could actually make it better at carrying multidirectional loads than concrete, since its anisotropy could be tailored to fit its exact use case. $\endgroup$ Commented yesterday
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    $\begingroup$ "Bone is not solid - it is hollow and once broken I'm sure it's structural strength is greatly reduced." Natural bone, with a marrow cavity, is hollow. Engineered bone would presumably be grown as a solid block or bar of cortical bone, without a central cavity. (Also, the concerns you raise about joining something as brittle as bone would also apply with greater force still to joining concrete, which is even more brittle than bone - and yet...) $\endgroup$ Commented yesterday

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