1413561 Prestressed composite beams R LIPSKI 4 Jan 1973 [10 Jan 1972] 551/73 Heading E1W A prestressed composite beam comprises a rigid elongate reinforcement element 1 having at least one flange e.g. 2, which element is longitudinally tensioned before concrete e.g. 6 is cast around at least part of it. The reinforcement element may be a steel girder or a composite steel and concrete girder, and in order to allow the tension to be applied nearer the neutral axis of the element, it may be augmented with an applied bending moment, as shown in Fig. 17. The tension may be applied on a small or a larger length or area of the element and other reinforcing members 13-15, prestressed or otherwise, may be added to the element or the beam. The method allows the use of a smaller upper flange than lower flange on the reinforcement element.
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