Analysis of Traditional Architects' Mastery in Technology and Final Form of Persian Lilipoush vaults

Barrel vaults are one of the component elements of curved roofs in Iran. They play a significant role in creating geometric forms and spatial quality. Among a variety of barrel vaults which are most widely used, annular ones have different construction methods. These annular vaults have various types of brick bonding. Among them, the brick bonding of Lilipoush vaults is very different. The use of limited materials in this type of brick bonding made it suitable for rural areas. An exploration into the formative structures and construction methods of Lilipoush vaults will lead to a better state of preservation and restoration of such vaults. This will also helpful in understanding the mastery of Iranian architects in applying geometry to architecture. This paper strongly believes that the buttress size and height of vaults, the availability of materials, and the mastery and creativity of traditional architects were all effective on the construction technology and brick bonding of Lilipoush vaults. The absence of this belief causes many previous studies to have a shallow understanding of the vaults and the type of brick bonding and geometric qualities they have. This paper tried to identify the geometry of annular vaults and the type of brick bonding used in Lilipoush vaults. The fundamental question of this paper is: How effective were the mastery and creativity of traditional architects at the construction method and final form of Lilipoush vaults? To answer this question, this paper adopted an applied research methodology with deductive reasoning. Data were collected based on library and field studies, observation and semi-structured interviews with traditional architects. The results indicated that the special brick bonding of Lilipoush vaults was an outstanding achievement in building annular vaults. In fact, the limited availability of materials and the mastery of traditional architects eliminated the need for wood supports and counterforts in this type of vaults. This can be partly because of the dry climate of the central villages of Iran which had limited resources of timber. Moreover, the simplicity of these vaults, and the fact that their construction needed almost no skills, made them popular among villagers who had not much skills and resources. Nonetheless, it should be noted that Lilipoush vaults are the fruit of architectural creativity and technical know-how of different master architects obtained within a long period of time. Given the elongation of the space (the proportion of the length to the width of the plan), architects applied different methods in building these vaults. These methods included unilateral and bilateral implementation as well as implementation with tiercerons. The thick rectangular space created by bilateral transverse walls has let the architects to rest the first courses of the roof on the corners without needing tier cons. By placing the brick parts under the roof courses, the roof gradually inclines inward covering the space. Here, the horizontal and vertical direction of the brick courses are combined with each other to incline toward the center and make the function of roofing possible.