Polygonal Shallow Intersection Shell


This form is suitable for a dome of large span which must be nearly circular in plan. If more than six sides are used, the rib formed by the shell gets rather shallow so a rib is added above the shell surface. Columns are shown in this sketch at the center of each panel rather than at the ribs. This would be suitable only for a small structure since it produces additional bending in the lowest part of the shell. As in other types of domes, a skylight may be placed at the crown of the dome. A thrust ring must be added to take the forces in the ribs. Windows may be placed in the shell except at the lowest points.