Roman Architecture and various questions.

[Freeman]

I have a few questions:

1) Are there any equations for architecture, i.e. a dome can withstand x joules of force, etc.

2) How do I make a dome??? I know its an arc turned 360 degrees, but how do I make one???

 

How do I make a perfect arc?

What is Roman cement made out of?

[atinymonkey]

1) Probably, but I have no idea. It's based around the weight of the dome pushing in, the circumference, the force of gravity plus the weight of materials. An architect could tell you.

 

2) Practically? The blocks are placed in concentric circles around a pre-constructed circular base and inclined inwards and then a keystone is placed in the top. The blocks are shaped once they have been put in place; the only masonry skill that’s important is putting the correct angle on the edges before placing in the circle.

 

3) Carefully.

 

4) Limestone ground to a powder and alluvial clay. They mixed in volcanic rock to form the more expensive cement. It was only used in foundations really.

[JoeSF35]

Remember that the angle and the shape of the individual blocks in the arcs of old were such that every member was in compression and held together with much friction. Because the concrete and cement were very weak in tension.

In a dome there will be tension in the lower portion.

 

Here is a good pdf with some mechanics and statics formulas

http://www.bath.ac.uk/~absdfda/DayalaIIIsemfinal.PDF