Abstract: The invention is concerned with a stiff flat girder which basically consists of a top- and a bottom chord (4a, 3b), compression members (ab) between and diagonal bracings (1a, 3a, 2b, 4b) in the spacings (a, b), in which both chords and all diagonal bracings are made of flexible cable/rope. It is preferred to let the main cables (1a, 1b; 2a, 2b; 3a, 3b; 4a, 4b) continue uninterrupted from one end (L) to the other (R) between the fixed supporting mountings (Lp, Rp; Lq, Rq), whereby the main cables (1, 2, 3, 4) at least once follow the direction of a diagonal bracing (1a, 3a, 4b, 2b). Furthermore it is preferred to have one cable of the top chord continue endlessly in one cable of the bottom chord, the cable circuit (4a, 4b, 34R, 3b, 3a, 34L; 1a, 1b, 12 R, 2b, 2a, 12L)formed being guided round the fixed mountings with controlled friction. A stiff, intrinsically safe, light girder structure is formed, allowing a great variety of architectural shapes, applicable for small up to the largest spans.

Abstract: A suspended roof is described, which mainly consists of a cable rope structure (20-27; 31-33, 35-37; 39, 40) coverable with a stiff weatherproof material. By the special way according to which the cables are led, passing over fixed mountings (8, 9, 10, 11) and/or other points-of-change-of-direction (8, 9, 10, 11; 28, 30, 37, 38), equalizing the tension in different cable parts (20, 21; etc.), together with the use of a minimum of stiff compression members (31; 43; 47) to form stiff girders after having tensioned the cable ropes to the design tension, a suspended roof is obtainable which is as stiff as a conventional stiff-girder-roof-structure. As a result a classic stiff roof covering may be applied to it. The ground plan coverable may have any shape, and need not be symmetrical.The described roof structure is stiff in contrast to the generally adopted tent-type suspended roof structure built from cable rope which is basically flexible.