Configuration processing and construction of large-span karbandi vaults: a case of the karbandi vaulting of Haj-Mohammad-Qoli Timche in Tabriz Historic Bazaar

Abstract

PurposeThis paper aims at discovering the traditional techniques of Persian architecture for covering large-span spaces with a kind of ribbed vault titled “Karbandi”. This structure is generated by intersecting several arches with a harmonic stellar geometry. Preliminary studies show that span factor affects the structural form of karbandi and large-span cases, despite similar architectural forms, have different structural systems and specific construction methods. The main focus of this paper is how karbandi has been designed and built on large-spans. To answer this question, the configuration and construction of a large-span karbandi in Tabriz Bazaar were recognized.Design/methodology/approachData collection of the research was initially done in three parallel directions through the archival study of restoration documents, direct observation of the corpus of the vaultings and interviews with the master mason of the Haj-Mohammad-Qoli Timche restoration team. Then by cross-referencing the gathered data, the construction process of the karbandi was simulated in Rhino 6 and Grasshoppers software and its BIM-M models were created in three levels of development: LOD300, LOD350 and LOD400. In the next step, the preliminary BIM-M models of the karbandi were presented to the interviewed mason and revised and completed based on his comments.FindingsAnalyzing the BIM models by reverse engineering, resulted in (1) Discovering a unique self-supporting masonry construction method applied for the erection of karbandi vaulting on large-spans. (2) Finding the effect of scale factor on the architectural and structural form of the karbandi vault. (3) Discovering the connection types of the karbandi vault based on the construction details.Originality/valueDespite the wide applications of karbandi vaults throughout history, very little information of their construction techniques is available. The techniques have mostly been experientially and orally passed down from masters to apprentices and rarely been documented. The quest to design and construct a karbandi vault is therefore like solving a puzzle whose most important guide is historical cases. Due to the geometric complexity of karbandi and its ability to cover large-span spaces, solving the puzzle can lead to achieving some technical ideas for masonry cross-ribbed vaulting. A great riddle of the karbandi vaults is how to design and build them on a large span.

Application-based principles of islamic geometric patterns; state-of-the-art, and future trends in computer science/technologies: a review

“…Master Lorzadeh , one of the last of his generation with a link to eighteenth-century traditions of master builders, believed in the drawing of karbandi based on the division of semicircle by the radiuses from the center of the span and its extension on the rectangular surface [22]. Other scholars believe that "the plan of an n-sided karbandi is on the basis of dividing a circle into n equal sectors and drawing intersecting equal chords between the dividing points [97][98][99]. Then, the final pattern is formed based on the funicular transforming of any lines of initial patterns, producing lattice structure or ribbed vaults [100].…”