EXPERIMENTAL STATIC BEHAVIOR OF INTELLIGENT PSC BEAM GIRDER USING UNBONDED COMPRESSIVE PRE-STRESSING

PSC hollow box beam girder with H-type steel as compression reinforcements is developed for bridge with a single span of more than 50 m [164.04 ft]. The developed PSC girder is equipped with unbonded compressive prestressing at H-type compression reinforcements. The purpose of unbonded prestressing is to recover plastic deflection of PSC girder after long term service by releasing the prestressing. A quasi-static 3-point bending test procedure with 4 different loading steps is performed to verify safety and plastic deflection recovery of the girder. The experimental results showed that the maximum applied load exceeded the design maximum load and most of the plastic deflection was recovered when the prestressing was released. The study results and analysis are discussed in detail. By using prestressed H-type steel as compression reinforcements in the upper part of cross section, repair and rehabilitation quality and cost of PSC girders should be greatly improved and significantly decreased, respectively.