Constructions Techniques of Roman Vaults

Opus caementicium represented a revolution in the history of construction since it allowed Roman vaults to span large areas thanks to the use of innovative structural solutions.

A significant example is the vault covering the Octagonal Hall of the Domus Aurea: the lower part starts as a domical vault, while the upper part is a hemispherical calotte ending at the oculus. What is unusual is that the Octagonal Hall is characterized by empty spaces where other rotundae are supported by full walls, and has radial rooms full of light where other rotundae are dark. The aim of this paper is to analyse, illustrate and discuss the construction techniques used to build the octagonal dome of the Domus Aurea, focusing on the innovatory used in combining the various elements in a way that guaranteed mechanical behaviour resistant to compression.