Domed membrane structure and method of erecting it

Abstract

A membrane structure having a frame constructed of radial supports that extend outward and downward from a common apex to the base. These support members are usually curved semi-arches or have a curved bight, are indirectly attached to each other at the apex and are normally secured directly to the base to oppose outward thrust of the lower ends and to anchor the structure. Outward thrust can also be opposed by an auxiliary circumferential tension member near the base. These supports can be precurved before erection or formed by "bowling" straight members during assembly and/or erection. The membrane cover supported by the frame is fabricated to curve inwardly between, at least, the curved bights of the supports to decrease membrane vibration, enable it to carry heavy external loads, oppose deflection of the supports and thus add stability to the structure. Strong membranes having deep inward curvature between curved semiarch bights act as structural members to oppose semi-arch deflection and buckling permitting the use of semi-arches with lesser strength which can reduce semi-arch size, weight, cross-section and cost. For some applications flexability can be safely increased to better absorb uneven wind forces. One erection procedure includes the folding of pre-curved supports into parallel planes in a prone position, lifting them to a vertical position, unfolding the supports to their erected position and erecting additional supports, if any. The membrane can be attached to the supports before they are lifted or after the frame is erected. Another erection procedure includes attaching non-curved support members to an apex assembly, lifting the assembly progressively as the support members are "bowed" to a configuration desired, the membrane installed and the structure secured to the base with or without a circumferential tension member at the base. The membrane can be tensioned by pulling it downward over the arches in an "over-bowed" state, by moving arches apart and/or outward. In some cases, an adjustable section between supports may be required.

Dependencies are inferred from the claim text.