INTERSECTION SHELL - CROSS FORM
Four cylindrical barrels intersect to form a central dome. The structure is supported by four columns at the corners of the intersection so that part of the barrel cantilevers from the central dome. Provision must be made for thrusts from the barrels and the central dome at the column. There are several alternates: 1) the columns may be made very heavy, 2) short lengths of walls in an angle shape may be used at the corners instead of individual columns, 3) diagonal members may be placed in each of the walls, or 4) ties may be place between tops of columns. The latter solution might be unsightly if the interior of the building should be clear.
Shell thicknesses for this structure should correspond to those used for barrel shells. The cantilever span of the barrels should not be made too large to take the bending forces.
The architectural advantage of this structure is that it appears to float in the air. Therefore, windows should be located so that this illusion is preserved.