The analyze of the historical construction system of the Iranian Architecture, Transition zone of the Dome, case study: Nizam-al- Molk dome in Iran

This thesis investigates the historical construction system and structural logic of Iranian architecture. then, by analyzing dome transition systems in Iranian architecture through a detailed case study of the Nizam al-Mulk Dome in the Jameh Mosque of Isfahan. It explores how Iranian builders achieved stability and enormous spaces without centering frameworks, relying instead on geometric precision, material intelligence, and modular construction principles. The research begins with a historiography of construction history in Iran, from the ancient civilizations in Iran through the contemporary era highlighting key figures, historical descriptions, institutions, and international collaborations. in the next step, the study examines the characteristics and evolution of Iranian architecture in different eras especially typologies of arches, vaults, and domes, analyzing their geometric configurations and structural performance across time. Particular attention is given to the squinch system, which played a crucial role in transitioning from square bases to circular domes and later evolved into complex compositions. The Nizam al-Mulk Dome serves as a pivotal example, represents the technical and symbolic culmination of Iranian architecture, where mathematical reasoning and craftsmanship converge to produce a stable, enormous and enduring structure. This dome was selected as the central case study of the thesis because its construction technique particularly in the transition zone is complicated, innovative and rich in different especial Iranian styles in the construction and structure solutions. Combining architectural analysis, structural behavior and historical sources, this research aims to reconstruct the underlying logic of Iranian dome construction, contributing to a deeper understanding of Iran architectural heritage within global construction history.