The Roman Arch

AQUEDUCT

TRIUMPHAL ARCH

VILLA

TEMPLE

Constructing the ArchThe arch solved the problem of finding a way to construct large buildings which had to support heavy weights. The arch was not a Roman invention but an Etruscan one.

The arch can bear huge weights and stand firm unless the stone of the arch collapses under the load. Each stone supports the one beside it and the stress of the weights goes down into the ground.

To build the arch the Romans used a wooden framework, called ‘centering’, between two walls and around it built up the arch using wedge-shaped block. When the keystone was fitted the wooden frame was removed.

Roman Concrete

Opus caementicium = Roman concrete was used extensively in the construction of Roman architecture.

Making Concrete

Quicklime was made by burning limestone (slaking), and adding water to produce calcium hydroxide, sand was then mixed in. The mix hardened forming calcium carbonate which bonded to the rough surface of the rocks.

How was it used?

Concrete was always laid between boxing to give it shape. To make concrete fill a layer of small chunks of rock (caementa) was laid between the boxing. Lime mortar was mixed and poured over the top of the rocks.

Types of Concrete …..

Opus incertum = a wall with small chunks of stone laid over the concrete core.

Opus reticulatum = a facing of small square blocks laid in a regular pattern in diagonal lines.

Opus testaceum = a facing of bricks laid in horizontal rows.

Draw an arch noting: keystone, trapezoidal, piers.ALSO, make notes on the uses of arches and how they are constructed.

P. 6 of Artus