Prestressed Tee-beams constructed by the split-beam method were tested to failure in flexure to study the behavior and ultimate strength of these beams and to compare their flexural characteristics with those of prestressed beams of conventional construction. The compressive portion of the cross section of the split-beam is cast after the web of the beam has been formed and prestressed. The variables in the study included the percentage of prestressing steel, strength of concrete in the compressive element of the composite split-beams, manner of prestressing and web reinforcement. Results showed that the composite split-beams behaved similarly to the monolithically constructed beams on the basis of flexural response and ultimate load. The strength of the concrete for the compressive element can be reduced within limits from that required for the prestressed element without sacrificing ultimate load capacity. The required percentage of reinforcing steel is less for the split-beam compared with conventional beams.
The rigidity and strength of two precast girders with welded splices of two different designs were determined in tests of the girders as beams continuous over three supports. The girders consisted of three reinforced concrete box sections welded and grouted together to form a beam 1-by 2-ft in cross section and 2 $ ft long.The splices located at points of inflection were formed by lap welding suitable lengths and amounts of positive and negative reinforcement projecting from the ends of adjoining sections and then grouting the pockets . The designs of the splices of the two girders were identical, except that girder No. 2 contained an additional amount of reinforcement consisting of three inclined stirrups of No, I 4 . bars on each side of the splice. The addition of the inclined stirrups resulted in an Increase of 6? percent in load carrying capacity of girder No. 2 as compared with girder No. 1, 1.
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