Development of Continuity Between Precast-Prestressed Concrete Beams Utilizing Post-Tensioning

摘要

The study presented utilized draped post-tensioned tendons, coupled over the interior support, as well as conventional bar and special prestressed reinforcement in the cast-in-place slab, to establish the continuity between the precast-prestressed beams. The results indicate that post-tensioned and prestressed reinforcement tend to restrain the formation of cracks and to close them when the load is removed. When the maximum negative moment is reached, moment redistribution takes place prior to collapse of the specimen. It was also determined that the actual positive moments are always greater than those predicted by elastic theory and conversely, the actual negative moments are always less than the elastic moments. The ultimate strength theory using the rectangular stress block was found to be safe for use in the design of the continuity connections. For the two-span beam tested redistribution of moments did occur allowing the member to carry the full ultimate load which would be predicted using limit analysis.