GB979836A - Improvements in or relating to prestressed composite steel and reinforced concrete structures - Google Patents

Abstract

979,836. Steel and reinforced concrete structures; bridges A. BIRGUER. Feb. 7, 1961 [Feb. 15, 1960; Dec. 5, 1960], No. 4487/61. Headings E1G and E1V. A composite steel and reinforced concrete structure comprises a reinforced concrete bedplate 5, Fig. 1, the reinforcement 10 of which is given an initial tension, after which the bedplate 5 is united to the metal part 1 of the structure by means of high tensile bolts 9, the reinforcement 10 then being further tensioned. The bed-plate 5 can be formed separately from the metal part 1, or can be cast in situ thereon. In the floor construction shown in Fig. 1, the bed-plates 5 rest upon the lower flanges of an I-sectioned steel girder 1. Concrete plates 2 are secured to the upper flanges of the girder 1 by high tensile bolts 3 and are formed with embedded tubes 4 of plastics for the passage of cables 14 for transversely prestressing the cast concrete floor decking 11. The cables 14 are partially tensioned one or two days after casting the concrete 11 and are fully tensioned ten to twelve days later. The floor is covered with flooring 15. In a bridge structure, shown in transverse section in Fig. 6, the reinforced concrete bed plates 19 are mounted internally on the bottom of channel shaped sections 18 which extend longitudinally of the bridge. The upper slab 16 of the bridge is prestressed by transverse reinforcements 17. The sections 18 are reinforced by internal struts and are connected by concrete partitions 24 which are prestressed by rods or cables 24. The composite structure forming the bridge rests at its ends on armoured concrete gantries 28, 29, Fig. 4.