Investigation of The Architectural System and Geometric Proportions of the Central Courtyard and Its Walls in The Historical Houses of Kashan (Case Study: Ten Historical Houses of the Qajar Period in Kashan)

The use of pavilions and geometric principles in the design and construction of buildings in Iran is one of its architectural principles, so that in most buildings from the past to the present it is well considered and buildings that lack it are considered worthless. The house is one of the most important man-made structures that meets various human needs. In the architecture of the center of the Iranian plateau, the house is composed of various components, the most important of which is the central courtyard as a small garden in the heart of the house. The central courtyard, while connecting all the spaces, meets a variety of needs as well. The city of Kashan is several thousand years old and has a rich historical context with valuable houses. According to research, it is likely that these houses have been formed with their beautiful and coherent architecture with special geometric thinking and systems, and geometric principles have been used to build them. Now the main issue of this research is what geometric proportions and architectural systems have been used in the design and implementation of the central courtyard and its walls. The purpose of this study is to extract the architectural systems and geometric proportions used in the design of the central courtyard of the Qajar period houses in Kashan and to investigate the frequency of each of them. This research is based on the method of analysis of architectural systems and geometric proportions of the courtyard and its walls in ten houses of the Qajar period in Kashan in order to extract the architectural systems and its geometric proportions. The statistical population has been selected based on the index of the building and the existence of sufficient data related to the research objectives. Also, in selecting the houses, an attempt was made to consider different scales of houses, from large-scale to small-scale in different parts of the historical area of the city. In terms of time, the studied samples are limited to the Qajar period. First, by examining the architectural systems and geometric proportions, three architectural systems, four, five, six and three geometric proportions √2, √3 and √4, were selected as the index geometric principles. Then, according to these principles, the map of the central courtyard of ten historical houses in Kashan was analyzed. The results of this study indicate that the entire yard is built with the previous design and follows the above architectural systems and geometric proportions. These systems and proportions can be seen in part and in general in the plans and wall constructions around the yard. Of course, this does not mean that all houses have all these six architectural systems and geometric proportions, but in some houses, some of these proportions and architectural systems have not been used. Architectural systems four and six with a frequency of 15 and proportion √3 with a frequency of 9 have been the most used and the courtyard of the Abbasid house with 14 architectural systems and geometric proportions is the richest house in terms of applying geometric principles.