The keystone
Compression
You have to support the structure (the actual arch) using a wooden form up to the point where you insert the keystone, after which the arch will be self supporting.
Metal and Steel ANSWER B: The majority of arch type bridges and viaducts were made from brick or stone. Concrete has also been used.
The key stone is the stone placed at the apex of the arch, and prevents the two sides of the arch falling in and collapsing.
It can be made out of any material but the has to have beams on it for obvious reasons. Hope this helped!
How did the indians build the arch
the key stone is the stone that is at the top of an arch. It is this stone that absorbs the majority of the forces stabilizing the arch formed
The arch of what?
Hankins Stone Arch Bridge was created in 1905.
Lalino Stone Arch Bridge was created in 1870.
Tusten Stone Arch Bridge was created in 1896.
Pithole Stone Arch Bridge was created in 1899.