Types and Forms of Shell Structures

HYPERBOLIC PARABOLOID - GABLED EDGE MEMBERS

Four rectangular units of the surface are used with this structure and are supported by gabled rigid frames at the outside edges. The ridges at the top, formed by the intersection of the surfaces, are also edge members of the individual panels. These ribs may require additional area which may be either on the top of the shell or may be placed below by constructing the form with a drop.

The stresses in this shell, if the rise of the shell is low in comparison to the span, are direct tension across the diagonals which sag, and direct compression across diagonals which are arched. The shell delivers forces to the ribs that are parallel to the rib.

A tie is shown connecting the knees of the rigid frame. The thrusts are quite high on the edge members. The member sizes must be quite large if the tie is omitted. The open space in the gables may be used for windows. The structure may be built continuously with units side by side to cover a large area.