Abstract: An auditorium has a domed roof formed by a first part spherical portion covering, without intermediate support, most of an amphitheatre accommodating an audience, and a second part spherical portion covering a stage adjacent the amphitheatre, the first portion being supported only at its periphery, and the second portion consisting of segmental leaves which can open about a common pivot supported by the first portion to uncover the stage, the common pivot being at a vertical axis of the second portion of the roof and above the amphitheatre and the vertical axis of the first portion being above the stage. Wall panels behind the stage can be moved apart to open the rear of the stage to the exterior.

Abstract: A structure is provided having two opposing nested pairs of outwardly convex roof arches mounted for rotation about a generally horizontal axis. Each pair of nested roof arches can be rotated about its axis from a lowered nested condition to a raised condition where the inner portion of one arch partially overlaps the other arch of the nested pair. In a preferred arrangement the arches extend between supports on diametrically opposing sides of a stadium building, which has an upper opening. The arches in their raised condition cover the stadium opening and in their lowered condition maintain the stadium substantially open to the elements. The turning moment exerted by the arches is sustained through struts by floats within liquid contained in caissons forming a foundation of the structure. The floats are shaped and guided to follow a path within the liquid as the associated arch rotates such as to substantially balance the turning moment of the latter as they move.

Abstract: A structure is provided having two opposing nested pairs of outwardly convex roof arches mounted for rotation about a generally horizontal axis. Each pair of nested roof arches can be rotated about its axis from a lowered nested condition to a raised condition where the inner portion of one arch partially overlaps the other arch of the nested pair. In a preferred arrangemnt the arches extend between supports on diametrically opposing sides of a stadium building, which has an upper opening. The arches in their raised condition cover the stadium opening and in their lowered condition maintain the stadium substantially open to the elements. The turning moment exerted by the arches is sustained through struts by floats within liquid contained in caissons forming a foundation of the structure. The floats are shaped and guided to follow a path within the liquid as the associated arch rotates such as to substantially balance the turning moment of the latter as they move.