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Cusquenian Concrete

Cyclopean Polygonal Concrete Moulds
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The great thing about Incan architecture is that the masonry work was so well constructed, and so expertly implemented, that many of their grandest structures survive today, despite being subjected to multiple earthquakes, and other forces that level lesser constructions within a matter of generations (Apparently, during earthquakes, the stones making up these buildings have been seen to "dance" only to settle back in their correct positions once things calm down)

The most exciting part of this construction technique was their use of interlocking irregular shaped stones to form some of the most spectacular dry-stone walling anywhere in the world.

Sadly, the skills that built these magnificent structures are all but lost to us today, but we can recreate some of the splendour of their works using carefully moulded concrete blocks.

First, the external, load bearing walls of a building are described to a computer programme, which tests various parameters and structural formulae for standuppability and nonfallingdowningness. It may be that walls angled slightly inwards as they get taller, prove most stable, and that style would certainly fit into the general Incan/MesoAmerican theme. Then, using maths, a tessellating pattern of cracks is calculated such that the monolithic design is broken down into pieces of a more manageable size - perhaps with such additional sophistications as having a notional gradient applied where larger sections tend towards the bottom of the structure.

Finally, each virtual piece is given a unique number, and a precise model made (let's say, from wax - I'm sure there's a better alternative, but everyone knows the lost-wax technique) around which a mould can be formed. The mould is then shipped to the construction site, where it can be filled with concrete (or, for a cheaper, possibly greener alternative, an aggregate of reclaimed building materials and concrete, or even a mud/straw/lie mixture) vibratified (a technique used for creating especially hard-wearing concrete) and allowed to cure. Once complete, the block is released from the mould, and can be craned into place (oh, I forgot to mention the integral crane mountings set into the moulding) for fitting.

The result is that the tricky part of moulding and shaping the stone is done back at the architect's/mould factory - leaving the relatively cheap task of assembly to the site team.

Furthermore, the resulting large-component structures (I'm thinking a 4 bedroom country house would be quite nice) ought to be exceptionally sturdy and long-lasting buildings. Careful planning and adoption of passive solar building design techniques may assist in the structure's green credentials.

zen_tom, Nov 04 2008

Imhotep http://en.wikipedia.org/wiki/Imhotep
Engineer, architect, physician and all round clever bloke. [DrBob, Nov 05 2008]

Maths http://www.dailymot...und-you-1-maths_fun
Please ensure you have your copybook at hand. It stands for
Mathematical
Anti
Telharsic
Harfatum
Septomin [theleopard, Nov 05 2008]

Dry Stone Walling http://www.newgroun.../portal/view/412167
To be honest, not much to do with it, but damn cool. [Loris, Nov 05 2008]

Verot Oaks Concrete Blocks http://VOBB.com
Just one of many examples that are evolving to meet building codes. Thusfar, what I've seen are prohibitively to ridiculously expensive and require specialist consultation to order and implement. [reensure, Nov 06 2008, last modified Nov 10 2008]

Incan architecture closeup http://en.wikipedia...ka_mauern_cuzco.jpg
[Voice, Apr 29 2010]

[link]






       Definately. The more building work that can be done off site and out of mud/rain the better.
MadnessInMyMethod, Nov 04 2008
  

       I have a question however. Again, using maths, if we discover what the inward camber of an Incan wall is and multiply it by the time it takes to mould the concrete, given that the structural integrity is such that the structure is left-mid of 12, how tall is Imhotep?
theleopard, Nov 04 2008
  

       //how tall is Imhotep?// Using maths, I'd say about 1/Millsy?   

       I was also wondering whether other materials might be better suited to this construction method - insulation type foam comes to mind - but I'm not sure how strong it would be. I do like the option of using reclaimed materials to form the new stone blocks though.   

       Roofs are trickier to engineer, but since there's likely to be a natural camber in these constructions, I suppose you could engineer a sort of domed solution.
zen_tom, Nov 04 2008
  

       You don't explicitly say what the starting point for the software actually is... Is it an otherwise complete design for a superstructure to be converted into a tesselated dry-stone version, or is it a more base set of parameters?   

       I would guess that if you just gave it height as a starting point it would always design a regular dome (á la Igloo).
Jinbish, Nov 05 2008
  

       //how tall is Imhotep?//

Although you are mixing up your ancient civilisations Mr theleopard (Imhotep was Egyptian not South American) the reference is, bizarrely, not inappropriate. Cyclopean architecture was one of his specialities! (linky).
DrBob, Nov 05 2008
  

       [Jinbish] I was imagining a primitive, monolithic prototype model being entered into the system (possibly minus internal elements such as floors and partition walls) and then having this broken down into interlocking pieces.   

       [DrBob] I believe the Imhotep thing is in reference to the BBC educational spoof "Look Around You" - I'd post a YouTube link (the 1st series was particularly funny) but can't access it from my current location.
zen_tom, Nov 05 2008
  

       dance? InCanCan!
po, Nov 05 2008
  

       Ah. So this is what getting old feels like.
DrBob, Nov 05 2008
  

       concrete cast by moulding is common. called precast, is done of site as this improves efficiency, shapes are modulated to suit transportation as well as erection.   

       using precast pieces as load bearing. quite common for engineering structures, such as bridges, using post tensioning as concrete performs very well in compression. not so much for buildings, it is more cost effective to cast load bearing structure in place if concrete, or assemble the support structure made up of fire rated steel, from which the precast is hung as cladding.   

       dry stone wall is assembling blocks without mortar. There is no way a load bearing dry stone wall could be approved under modern building codes, it would be flimsy and unstable, does not inculate, or prevent moisture or vermin egress. dry stone walls don't perform better in earthquake, modern buildings are designed with structural dampening accounting for building harmonics which reduce or remove the impact of earthquake shock.   

       the remaining idea is incan style dry stone walling for housing. dry stone walls would not be moisture or vermin proof. the internal would have to be lined with moisture proof plasterboard. roof elements would not be able to load to walls due to building code restrictions. this can be done more cost effectively with spraycrete over structural mesh or similar.
williamsmatt, Nov 06 2008
  

       Prefabrication? Is that really an invention? Last i checked the Inca (plur,sing, nom,poss{?}) quarried the stone off site and moved it to the construction. You are proposing that we prefab concrete off site in large, non uniform, rectanguloids and stack them for massive (both ways) construction projects? Please, this is taking ancient worship a wee to far for my tastes. A perfect dry stacked wall is strong and stable but very limited in the shapes it can form which is why the ancient world was so obsessed with pyramids: other shapes were weak. Some things have gotten WAY BETTER. Construction is definitely one of them.
WcW, Nov 06 2008
  

       //spraycrete over structural mesh or similar// I've looked at spraycrete in the building of monolithic domes - a domed balloon is inflated, stacked with rebar and then spraycreted from the inside, to impressive results. The problem with large, poured-(or sprayed)in-place concrete is managing expansion, and putting off decay caused by corroding reinforcement bars (I'm thinking of the sad future for Frank Lloyd Wright's Fallingwater here). By having large, but separate sections of concrete that's been cast jigsaw-like in order to key into its surrounding stone, you gain strength while continuing to allow for expansion. Some of the blocks I'm envisioning here would be about the size of a small-to-medium sized car. The walls of such a building would naturally be very thick.   

       I challenge the permeable to vermin/building regs thing - yes, traditional drystone walling is full of holes - but the idea here is not so much for drystone walling (although a good way to describe the concept) it might be better described as a mortarless system - preferable since mortar (like the rebar in reinforced concrete) is prone to decay over time without periodic maintenance.   

       As for building harmonics, by using more material, you dampen the harmonics in the simplest way possible. Think of it more as computer enhanced earthworks implementable by anyone with enough ambition and a crane. (i.e. Building codes - schmilding codes)   

       And the idea that a building's configuration is a function of whether it uses mortar or not is nonsense. An arch for example, is held in place by the configuration of the component stones (the keystone and others having been cut to fit), not by the mortar 'sticking' the bricks together. The mortar is there to serve as a means of negating imperfections in the intersecting surfaces, I'm suggesting that we may be in a position now to create the surfaces of building materials with such fine tolerances, that we may not need mortar anymore.   

       As it happens, over time (I would imagine) a natural mortar would accumulate in any gaps as they collect dust, residue and the occasional vegetable. And for dressing the inside, stone buildings have had internal cladding for years (think timber panelling in those big old country houses) but that's up to the inhabitants.   

       [edit] I mentioned Fallingwater earlier on, and concede that there are some shapes that this method of building wouldn't be able to successfully accomplish - big cantilevered sections like that would be impractical - but then, aren't they always?
zen_tom, Nov 06 2008
  

       WcW - you do realise that modern construction isn't built to last? Buildings may be taller, but they'd collapse in just a few years without maintenance.   

       Perhaps the Incan buildings which wern't capable of dancing in earthquakes fell down ages ago? If so, the surviving structures may have further useful clues.   

       I'd like the system to be capable of incorporating any large boulders you already had to hand, or liked the look of.
Even better, you'd show it what natural stone you had and it would carve the pieces to fit with minimal wastage. The Inca apparently got good joins by trying the bits together then smashing off the non-complementary bumps with other rocks. An automated system of laser-scanning and machine-controlled cutting could be much more efficient.
Loris, Nov 06 2008
  

       Natural rock boulders are probably more expensive than concrete before you even begin carving. But it is much more aesthetically pleasing. Since there are systems which will laser-scan a statue then automatically carve a block of stone to match, it's obviously possible. I'm not particularly against using cast concrete - maybe you could use different types of concrete in neighbouring blocks? This would help emphasise them and prevent the building becoming the generic grey mass most concrete buildings are.   

       Plus, tell me more of this vibratifying technique. Google provides precisely one relevant hit : this page.
Loris, Nov 07 2008
  

       Ahh, vibratification - a common enough technique wherin once the concrete has been introduced to its mould, a great big vibratificationiser is introduced into it and switched on. The resulting vibratifications cause the gloopy material to find and settle into any gaps and crevices, resulting in an overall denser aggregate than that resulting from an unvibratified stratum.
zen_tom, Nov 10 2008
  
      
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