Geometric Proportions in the Structure of Mazey Arches in the Sasanian Period Vaults

Abstract

The Sasanian period of architecture is regarded as one of the most brilliant artistic and engineering construction periods in pre-Islamic Iranian history. This era, which began in the 3rd cen- tury CE, not only inherited the engineering knowledge of its predecessors, such as the Achaemenids and Parthians, but also introduced significant innovations in spatial and structural design. One of the most prominent architectural features of the Sasanian period is the use of massive and tall vaulted arches with semi circular arches, allowing architects to create vast spaces without columns. The design of these arches, especially in large iwans and massive domes, required mastery of geometric and mathematical principles. The main objective of this research is to identify the arches used in Sasanian-period vaults to uncover the hidden geometry in the design and construction of these structures. This study employs a descriptive-analytical method with an emphasis on the application of geometry in architecture to examine the arches used in buildings from this period. The results indicate that the arches employed during this period are of the “mazey” type, utilizing geometric ratios of 2:1, 3:2, and 4:3 in their plan designs. Additionally, circular geometry and geometric curvature principles were applied in the design of these arches to optimize load distribution. Therefore, these structures are not only regarded as a technical achievement but also demonstrate a visual representation of order, symmetry, and balance through the use of precise geometric proportions. Ultimately, it can be stated that Sasanian period architecture extensively utilized geometry in the design and construction of buildings, particularly concerning ratios, scales, and complex structures, with engineers and architects possessing complete mastery of geometric principles to achieve stability and beauty in their constructions.