Geometric pattern and spatial structure of Iranian plain caravanserais, with emphasis on Khorasan plain caravanserais

This study investigates the suburban caravanserais on the plateaus of Iran in terms of geometry and spatial structure in the three periods of Seljuk, Safavid and Qajar, which are the most active Islamic periods in the construction of such buildings. The present study also attempts to find the position of Khorasan plain caravanserais in this area. The process in this study includes the selection of caravanserais and characteristics, their classification and analysis, and achieving a conclusion. In this research, researchers, utilizing library studies and existing documents including specific sources and general histories, travelogues and recent research on caravanserais based on argument and using purposeful sampling method (non-probable), examined more than fifty samples of caravanserais. After reviewing the caravanserais and classifying them in terms of the historical period, geographical location, geometry and dimensions, the caravanserais were compared and analyzed. Examining the suburban caravanserais geometrically, it is clear that most of them have a square or rectangular plan, and some of them have taken on octagonal or circular shapes due to the provision of solutions. Meanwhile, Khorasan caravanserais such as Robat Sharaf, Robat Mahi and Robat Zafaranieh have often used quadrilateral geometries and four-porch patterns. The results demonstrated that the spatial structure of the caravanserais is sometimes mixed with non-service functions, and this issue can be clearly viewed in Robat Sharaf Khorasan, which has two prayer halls and two courtyards. The results also showed that over time and with the development of roads, caravanserais became more spacious, and in this regard, Sabzevar Zafaranieh Caravanserai, which had a reservoir on its southwest side, is an appropriate example.