GB720313A - Improvements in or relating to reinforced concrete beams - Google Patents

Abstract

720,313. Beams; floors. UDALLS PRESTRESSED CONCRETE, Ltd. March 26, 1953 [March 26, 1952], No. 7768/52. Class 20 (4). A reinforced concrete beam is made by arranging reinforcements in a channel-shaped member, or more than one aligned channelshaped sections, the reinforcements being tensioned, against the compression reaction of the sections, before the in situ concrete is filled into, and above, the channel. As shown in Fig. 1, the sections 11 are open at one end and closed by a wall 13 at the other end, the wall having passages 15 for the reinforcements 17. The sections are aligned with grouting between them, with the wall 13 of each section against the open end of the adjacent section, except in the middle of the beam where two walls 13 abut. The reinforcements are tensioned, by any suitable means, and are retained by being embedded in concrete in the end sections. When the assembly so formed is in position in the building, the channels in the sections 11 are filled in with concrete which extends above the side walls of the channels and may be integral with in situ concrete extending laterally from the beams to form a floor. Some of the reinforcement rods may be tensioned after the setting of the in situ concrete to post-tension the same, and in some cases, the reinforcements may rise at their ends out of the general plane of the reinforcements. The sections 11 may have orificed walls 13 at both ends, and the concrete may be filled into the channels before the assembly is in position in the building. A number of beams may be laid side by side to form a continuous support for the concrete forming the floor which is post-tensioned by reinforcements running transversely to the beams. The depth of the beam may be increased as shown in Fig. 6 by side slabs 23 which may be retained in the permanent structure. The slabs 23 preferably have a corrugated or toothed lower edge to fit correspondingly formed edges of the sections 11. The sections 11 may each be in the form of a cross, Fig. 10, so that a grid-like structure may be built up, the reinforcements passing through holes in the walls 34 or through clearance spaces 35 beneath the walls.