Abstract :
Little has been written about the structural behavior of conical shells, while conical shells construction techniques due to the high rise and small span has always required special attention throughout the history of Islamic architecture. This paper aims to examine how conical shells bear weight loads and resist against bending through a qualitative analysis. After proving that rise/span ratio strongly affects weight loads and bending in external shells, the main question of the paper is what construction techniques architects adopted to carry weight loads, and how these techniques differed in domes with various rise/span ratios. To find out about paperʹs main question, a qualitative approach for structural analysis has been adopted. First, architectural maps and dimensions of six cases were documented, and then, according to the documentation, some ratios and parameters have been defined to find their probable correlation with rise/span ratio. Results show that to restrain weight loads in external shell, design of stiffeners and thickness of the conical shell play a crucial role to keep structure balanced. According to the results, rise/span ratio has a positive correlation with thickness/span, height of stiffeners/span, stiffeners sectional area/span, gradual decrease of thickness and number of stiffeners/ number of flat planes. In contrast, Rise/span ratio does not have any meaningful relationship with stiffeners end point and struts end point, and has a negative correlation with the number of flat plains.
