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We have been building brick walls and brick domes for years. Recently we made our first groined vault ceiling.

I need help on the "cornors".
I am not sure about how the "cornors" are to be cut as I have only seen pictures of groined vaults. Did we do it right?

Here is putting in the first brick on a new arch. We cut out the TOP of the springer brick it is springing off of so that it is touching only on the intrados like the other bricks. Note the first time we cut it all wrong but left it.
S771.jpg
Comments?

Belows is the finished product.

S805.jpg

Before putting a slab on top we put 300Kgs (660lbs) on a square meter.
We are really excited about this skill as for us it is cheaper than a wood floor. And of course it is unbelievably attractive.

We built without formwork but used hooks to hold the brick until a arch was completed. Mortar is mud/sand.

Second question is why does the arch bow out when me make a arch on its end?

Please excuse the rough walls, this is to be my workshop / garage.
 

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The downward force of the arch is deflected outward. If the walls are not strong enough to hold the lateral stress it will collapse. You either need enough mass to hold the lateral force or buttresses to deflect it back into a vertical direction.
 

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Hopefully that project was overseen by a structural engineer. :blink:
 

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Discussion Starter #7
Could you explain more how you supported the brick without forms?
I use mud/sand mortar in same ratio as making bricks (we manufacture). Mud is the trick, sand stops cracking.
You build with only slightly damp brick (only 2 seconds in the water), or even dry. (jury is still out on this, but it should not be anywhere near as wet as if you are building a wall with cement lime mortar). The mud mortar (sometimes with a little cement) acts like glue and the capillary action of the water being sucked into the brick will hold it in place.

We also have a 8mm rebar hook , it holds the brick by a light string pulled back. with plain vaults we dont use the hooks, dont need them as much and it slows you down.

I learned alot from the website of Auroville,

I cant post a url until i post 13 more posts.

like this page-
www earth-auroville dot com /?nav=menu&pg=vault&id1=4
remove the spaces and replace dot with .


Also search on Nubian Vault. Middle east built like this for like 4 thousand years.

I can also post some more pics where you see in between steps.

if it is a steeper catenary curve it is easier. This one we wanted to push the limit on lowest rise, as it is ceiling floor.
 

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Discussion Starter #8
I have a proper ring beam and columns. My question is how to cut the brick when you start a new row. Your example is for a simple vault. I am talking about a groined vault. my forces are only in the cornors.
 

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Discussion Starter #10
This shows how we build without formwork.
I think this shows the hooks, although you can build without. This is a plain vault and rise is about 1/10 of span.

S722.jpg
 

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Fundi, where are you located? This method of vaulting is very interesting. I have studied Catalan vaulting, which also uses no centering. Are you familiar with this? I think the answer to your groin vault question would lie in the use of ribs underneath the groin to hide that joint. The problem would be that you would need centering to build the ribs. It should make it much easier to build the webs in between though...
 

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Fundi, typically on a groin vault the masonry runs perpendicular to the outside walls and not parrallel such as your example. If you do not have ribs to butt your masonry into, then you would need to have compound miter cuts which would not be easy. I posted some examples of what I mean. Is the brick you are using a typical Bovedas brick? Thanks for posting your work and explaining your methods of hooks. Good idea!
 

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Hey thanks for sharing fundi...you have more pics? I didn't see the rebar hooks you used in the last one.

If/when I ever build a home it will have one brick ceiling...to me they are the absolute best look going.

Thanks for posting.
 

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Discussion Starter #14
Fundi, where are you located? This method of vaulting is very interesting. I have studied Catalan vaulting, which also uses no centering. Are you familiar with this? I think the answer to your groin vault question would lie in the use of ribs underneath the groin to hide that joint. The problem would be that you would need centering to build the ribs. It should make it much easier to build the webs in between though...
I am in Arusha Tanzania.

Thanks for bringing up Catalan vaulting. I had seen pics before but only now do I realize it is different than what I am doing. Just spent hours searching on it, and I will try on a staircase it will fit in nice.

I dont see how they get bricks to stay up while building without centering with catalan vaulting. I guess i could try hooks. With nubian method the large surface adheres well, with catalan it appears more difficult. Have you seen pics in process without centering?

I don't necessarily want to hide the joint, but i do want to avoid centering as wood is relatively expensive here. I was more asking in terms of strength. I think we have it right, but thought someone might have a trick for us.
 

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Discussion Starter #15
Fundi, typically on a groin vault the masonry runs perpendicular to the outside walls and not parrallel such as your example. If you do not have ribs to butt your masonry into, then you would need to have compound miter cuts which would not be easy. I posted some examples of what I mean. Is the brick you are using a typical Bovedas brick? Thanks for posting your work and explaining your methods of hooks. Good idea!
in your first pic did you use centering during construction or?

I use same brick that I use on walls. It is 240x115x72 mm. any suggestions on changing the size for vaults appreciated.

I ran parallel so as not to use centring. I just looked back and i think i like the look parallel
 

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in your first pic did you use centering during construction or?

I use same brick that I use on walls. It is 240x115x72 mm. any suggestions on changing the size for vaults appreciated.

I ran parallel so as not to use centring. I just looked back and i think i like the look parallel

Fundi, it is impossible to lay the brick parallel and have the brick come together nicely. Here are some more pics of ways you can do it. If you are good at math I can send you some sites that deal with laying out a groin arch. I hope the pictures are helpful. The pictures were downloaded from www.anton-groell.de/english/vault.html
 

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Fundi, it is impossible to lay the brick parallel and have the brick come together nicely. Here are some more pics of ways you can do it. If you are good at math I can send you some sites that deal with laying out a groin arch. I hope the pictures are helpful. The pictures were downloaded from
thanks Denver,

Thanks for the pics, always trolling for pics like that. (actually have that site bookmarked)

Yes please send the sites with laying out a groin arch. I am okay with math.

I cant send links yet until i post more.
these guys at earth-auroville.com then on pages

VAULTED STRUCTURES
* * *

EQUILATERAL GROINED VAULT
you will find some pictures including these.
image44.jpeg
image45.jpeg

They do it parallel but now is see they use a thicker brick for the groin and alternating the way they lie.

I would go perpendicular but then i cant do without centering, at least I dont know how right now.
 

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Here are a couple of pics i have been saving of vaulted brick ceilings. I have shared them before here but thought that I would throw them into this thread again.



 

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thanks Denver,

Thanks for the pics, always trolling for pics like that. (actually have that site bookmarked)

Yes please send the sites with laying out a groin arch. I am okay with math.

I cant send links yet until i post more.
these guys at earth-auroville.com then on pages

VAULTED STRUCTURES
* * *
EQUILATERAL GROINED VAULT
you will find some pictures including these.
View attachment 15063
View attachment 15062

They do it parallel but now is see they use a thicker brick for the groin and alternating the way they lie.

I would go perpendicular but then i cant do without centering, at least I dont know how right now.

Fundi,

Look closely at the pics you sent me and you can tell they are not laying the bricks parallel to the outside walls, but on a 45 degree like the second pics I sent. Also Joe Bartok is a construction math genius, of which I'm far from and I am sending you a site which might be helpful. It is http://ca.geocities.com/web_sketches/
 
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