GB744756A - Improvements in or relating to prestressed concrete floor, roof and like structures - Google Patents

Abstract

744,756. Floors, roofs and beams. GILBERT-ASH, Ltd., and PRE-STRESSED CONCRETE CO., Ltd. Aug. 24, 1953 [Aug. 28, 1952], No. 21656/52. Class 20(4). A method of assembling a prestressed concrete grillage for a floor or roof comprises erecting prestressed primary beams in parallel relation. ship and thereafter fitting between the primary beams and at right angles thereto, aligned elements 2, Fig. 1, which coact with parts of the primary beams to form secondary beams, the latter being prestressed after being placed in position. Each primary beam comprises a number of elements 1 with end units 3, each element 1 having an upper boom 5, a lower boom 6 and spacing members such as 7, 9. The lower boom 6 has channels 10, 11 to receive high tensile wires which are stretched and anchored at their ends. Each secondary beam element 2 comprises an upper boom section 12, a lower boom section 13 and spacing members 14, 15, 16, the boom section 13 having channels 17, 18, to receive high tensile wires which pass through apertures in the primary boom sections 6. Each secondary beam has end units 4. When the grid has been assembled, thin square deck elements 20, Fig. 7, are supported on the upper boom sections 5, 12, the elements 20 having a plane upper surface and a slightly domed undersurface 21. A finishing screed may be applied on the deck elements.