Effect of strand debonding on the shear strength of existing pretensioned PC hollow slab

Pretensioned PC (prestressed concrete) beams experience strand debonding failure at the ultimate loading stage, which leads to bond-loss failure of the beams. To study the effect of strand debonding on the shear strength of pretensioned PC hollow slabs, the existing PC hollow slabs of 19 specimens with spans of 10, 13, 16 and 20 m used in Chinese expressway bridges were loaded to bond-loss failure. The strand slip, bond- loss failure mode and shear strength of 19 specimens and 31 shear tests were analyzed. The test results showed that the angles of the failure diagonal cracks were not consistent with the Ross model. Therefore, a refined model to predict the shear strength subjected to pretensioned PC hollow slabs was developed. Other factors were also considered in the refined shear strength model, including the dowel action of longitudinal reinforcements, the prestressed strand development length and the compression zone height. Compared with the shear failure controlled by strand yielding, the shear strength controlled by strand debonding was decreased by approximately 27 %. The test results showed that the debonding induced bond-loss failure could be described as follows: after the formation of the failure diagonal crack, the strand will clearly slip, and concrete parts on both sides of the failure diagonal crack rotate around the crack tip. Due to the debonding induced bond-loss failure of the pretensioned PC hollow slab, the shear strength could not be improved even by increasing the concrete strength of the compression zone. Finally, the validity of the refined model was verified by 23 test specimens.


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  • Accession Number: 01887939
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 19 2023 9:38AM