Membrane structure

A membrane structure comprising:

• an airtight pressure-resistant gasbag including a plurality of spindle-shaped gores of an airtight membrane material, adjacent gores joined together at edges, and a plurality of reinforcing ropes attached to joined sections of the edges, the reinforcing ropes extending along the edges, respectively;
• and
• a shape maintaining mechanism which maintains the gasbag in a predetermined shape when the gasbag is in a fully inflated state;
• each of the gores outwardly protruding between two adjacent reinforcing ropes extending along the edges of the gore, respectively, without elongation of the airtight membrane material, when the gasbag is in the fully inflated state;
• each protruding gore having a radius of curvature in a direction intersecting the two adjacent reinforcing ropes, the radius of curvature being smaller than a radius of the gasbag;
• each protruding gore being subject to a tensile force which is directed in the direction intersecting the two adjacent reinforcing ropes.