The Typology of Transition Zones with Shouldered Arches in Iranian Seljuk Structures

Squinches have been historically employed to facilitate the smooth transition from a square base to a circular dome in the transition zone beneath a dome. Their origin dates back to ancient Iranian architecture, and they were invented to address the challenge of supporting a dome on a square base. The shouldered arch style of squinch was initially used in Sasanian architecture. Over time, in Iranian-Islamic architecture, the transition zone with shouldered arches evolved, with Seljuk buildings representing the epitome of this development. The architectural style that emerged during the Seljuk dynasty (1037-1194) in Iran is referred to as Seljuk architecture. This study focused on the transition zones of Seljuk structures with the shouldered arch style of the squinch, examining their typology. The features of the transition zones of eleven case studies were converted into matrices, and the MATLAB programming platform was used for analysis. The findings of this research identified six types of transition zones that are composed of shouldered arches in Iranian Seljuk structures.