### <center>Catenary arch</center>

>A catenary arch is a type of architectural pointed arch that follows an inverted catenary curve. It is very common in nature, cathedrals and in Gothic arches used in Gothic architecture.*It is not a parabolic arch*.

<center>![landscape-arch-utah9730b.jpg](https://steemimg.com/images/2016/09/10/landscape-arch-utah9730b.jpg)</center>
<center>[Image credit](https://speakzeasy.wordpress.com/2015/06)</center>

**A natural bridge retaining a catenary  profile after several million years of erosion by water and wind, optimally fitting itself to the strongest curve possible**.

A sustainable construction  method making use of the centenary arch/curve known as Timbrel vaulting or *Catalan vaulting* or *Gusatavino vaulting* in the USA, was refined in the 14th century around the Mediterranean, although its precise origins are unknown people have been building in this technique for thousands of years in upper Egypt. 

###  <center> Early geomimicry in Africa</center>

<center>![Screenshot_1f1892.jpg](https://steemimg.com/images/2016/09/10/Screenshot_1f1892.jpg)</center>
<center>[Image source](http://www.lavoutenubienne.org/en/nv-technique)</center>

###  <center> Further refinements in Africa</center>

<center>![75fe70f9f780931bd8f5b6ce0a96ca3ab0e82.jpg](https://steemimg.com/images/2016/09/10/75fe70f9f780931bd8f5b6ce0a96ca3ab0e82.jpg)
[Image source](https://www.pinterest.com/pin/432556739181517579)</center>

>The resulting vault does not rely on gravity but on the adhesion of several layers of overlapping terracotta tiles which are woven together with *fast-setting* mortar, hence is self-supporting apart from some temporarily required light form-work. Adding two or three layers makes the resulting laminated shell almost as strong as reinforced concrete.

###  <center> Golden times in Europe; 1600s'</center>
<center>![llotja_valencia24882.jpg](https://steemimg.com/images/2016/09/10/llotja_valencia24882.jpg)</center>

###  <center> Guastavino; the satoshi of thin vaults, pictured standing on a vault below Introduced Catalan vault to America</center>

<center><img src="https://steemimg.com/images/2016/09/10/guastavino_1de073.gif" alt="guastavino_1de073.gif" border="0"></center>
<center>[Image soure top & bottom](http://www.lowtechmagazine.com/2008/11/tiles-vaults.html)</center>

### <center>Convincing the public in USA; 1900s'</center>

 <center>![6a00e0099229e88833010535eef8dc970c-800wi9b829.jpg](https://steemimg.com/images/2016/09/10/6a00e0099229e88833010535eef8dc970c-800wi9b829.jpg) </center>

>The result defies common sense, because a timbrel vault is very thin compared to a Roman vault, while at the same time it is capable of bearing much higher loads. This of course enables wider spans and gentler curves.

###  <center> New Era begins, Guastavino builds thin vaults in USA; 1900s'</center>

<center>![Grand-Central-Oyster-Bare42ab.jpg](https://steemimg.com/images/2016/09/10/Grand-Central-Oyster-Bare42ab.jpg)</center>
<center>[Image Source](http://moneyinc.com/top-five-power-lunches-new-york-city)</center>

###  <center> New Era begins again, The millenium and beyond; computers push the limits of the thin arch; 2000s'</center>

<center>![timbrel-photo47350.png](https://steemimg.com/images/2016/09/10/timbrel-photo47350.png)</center>
<center>[Image source](http://www.treehugger.com/green-architecture/classic-timbrel-vaults-built-computers-and-3d-routers-reinventing-minimalist-technology.html)</center>

### References

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

http://www.block.arch.ethz.ch/brg/project/free-form-catalan-thin-tile-vault

http://www.lowtechmagazine.com/2008/11/tiles-vaults.html

http://www.treehugger.com/green-architecture/classic-timbrel-vaults-built-computers-and-3d-routers-reinventing-minimalist-technology.html