GB746009A - Arch beam - Google Patents

Abstract

746,009. Concrete beam, or arch. BILLNER VACUUM CONCRETE SOC. ANON. May 24, 1954, No. 15193/54. Class 20(4). A beam, or arch, differs from conventional structures which have their intrados and extrados defined by dissimilar curves and are either of uniform thickness, or have progressively increased thickness from their apices towards their spring lines, in that the intrados and extrados are of identical curvature so that the thickest portion of the arch is at the apex from which it progressively decreases in thickness to the springing lines. An arch 10, Fig . 1, has its lower surface, or intrados, 12 identical in curvature with its outer surface, or extrados, 14 which serves as a form for the next adjacent arch 16 whose intrados complements the extrados 14. An arch 20 is cast into the arch 16 so that its intrados complements the extrados of the arch 16. Reinforcements 22 are provided near the springing lines. Arched beams 10, 16, 20 are arranged side-by-side to form a floor or roof structure, Fig. 2, and are supported by a surface 28, the joints between the arches, filled with concrete 30, which in the case of roofs serve as gutters, having reinforcements 32. This structure may be covered either internally or externally or both. An arch can be cast in sections with reinforcements projecting therefrom, the sections being united by casting narrow strips of concrete around the reinforcing members.