Types and Forms of Shell Structures

DOMES - SQUARE IN PLAN

This structure is a spherical dome with portions sliced off to form a square or rectangle. Most areas to be covered are rectangular so a circular dome is not always a good solution to the planning requirements.

This dome is supported by four rigid frames and would only be suitable for small spans because the frames would get quire large. For long spans, it is necessary to place a tie between the knees of the frame. These ties can be made a part of the window mullions if it is desirable to conceal them.

Stresses in the shell are direct compression (membrane) stresses except across the corner where there are direct tensile forces due to the outward spread of the forces. The arches, or rigid frames, pick up the shell forces by shears parallel to the arches which are zero at the top and maximum at the bottom. There is no component of force in the shell perpendicular to the arches.