Patent GB-743159-A (GB)
Title: Improvements in or relating to building constructions
Inventor: GODENIR ALBERT
IPC: E04C5/12
Filed: 1953-10-21
Abstract: 743,159. Silos; girders; roofs; walls; reinforced concrete. CEMENTATION CO., Ltd. Oct. 19, 1954 [Oct. 21, 1953], No. 29067/53. Classes 20(1) and (20(4). A prestressed concrete building construction comprises at least two beams formed from a series of coplanar concrete blocks placed end to end, the beams lying in intersecting planes being connected together by a knuckle block device round which passes loops of two tensioning cables one of which encloses and prestresses each of the beams, the loops being arranged to intersect and means being provided to maintain the loops apart after the cables have been tensioned. Walls 1, 2, 3 of a silo are formed from concrete beams connected edgewise to form corrugations. The beams of each wall are joined edgewise in pairs, e.g. 11, 12 and 15, 16, in walls 1 and 2 respectively which are joined endwise by knuckle joints 5 to form a half arch. Pairs of half arches are joined by articulations 4 and these arches are placed side by side to the required length and then walls 3 fill in the ends. The beams are made up of prestressed concrete blocks 20, reinforced concrete blocks 21 and metal mesh.reinforced glass windows 22 which fit into rebates in blocks 20, 21. Each block 20 is cast with protruberances 25 and preferably blocks 21 are cast between the blocks 20 in their final position in the assembly so that dimples 28 are formed to correspond with the protruberances 25. If the arrangement of protruberances 25 is different on each block 20, the blocks 20, 21 may only be assembled in the positions in which they were cast and the fit will be sufficiently accurate to make mortar jointing unnecessary. The prestressing wires 24 and reinforcing bars 29 of blocks 20, 21 respectively project at the sides of the composite beam. This beam 31 with an adjacent beam 32 forms a composite V-section twin beam which is placed in a former at an angle to a further pair of beams 33, 34 forming a second twin beam so that the knuckle joint may be formed. A knuckle block 35 is applied to the upper end of beam 31 and is thickened to form face 35A lying in the plane bisecting the angle between beams 31, 33. Below face 35A, there are projections 37, 38 separated by window 39. Lower faces 37A, 38A of protrusions 37, 38 lie in a plane perpendicular to the longitudinal axis of the beam 33. A similar knuckle block 33A fits on the end of beam 33. A block 42 is placed at the lower end of beam 31 and a block 43 is placed at the upper end so as to overlie block 33A. High tension steel wire 44 is wound round the periphery of beam 31 and blocks 42, 43 between the protruding prestressing andreinforcment wires and bars 24, 29 and the grooves in blocks 42, 43. Similarly, tension wires 46 are wound round beam 33 whose lower terminating rod 45 overlies block 35. One or more hydraulic jacks J force blocks 43, 45 apart and key stones K are inserted as shown to maintain cables 44, 46 under tension. Similarly, beams 32 and 34 are joined by a knuckle joint. As blocks 42 are semi-elliptical the resultant of the compressive forces produced by the wire 44 acts through the foci of the ellipse and these foci are arranged to be where blocks 21 contact block 42 and not where windows 22 contact block 42. Beams 31, 32 are joined edgewise by twisting together reinforcing or prestressing wires as at 70, Fig. 15, or twisting together the wires 73 in adjacent beams, Fig. 16, to locate tensioning cables 44, 44A and applying concrete 71 with reinforcing bars 72. Prestressed concrete ties 74, Fig. 1, have their prestressing wires incorporated in these junctions. Blocks 35, 36 contain prestressing wires and are joined edgewise similarly; The lower edges of the walls are connected to the foundation by articulations. Conveyers are provided for introducing material to and removing material from the silo. In a modification, Fig. 18, the knuckle block is cast in one piece with integral portions 90, 91 aligned with beams 31, 33 and an integral ear 92 with protrusions 93, 94. A block 43 is laid on ear 92 with the cable 46 in position, the cable is tensioned by a jack and blocks 96 are inserted and the jack removed. Cable 46 of beam 33 extends round a D-piece 98 and may be tensioned by a further knuckle at its other end.