Full-Scale Testing of Pretensioned High-Strength Concrete Girders with Debonded Strands

The flexural and shear behavior of three full-scale pretensioned high-strength concrete (HSC) bridge girders, which were designed to a modified bulb tee (BT) section according to AASHTO specifications, were investigated experimentally to evaluate the applicability of high-strength concrete and a higher percentage of debonding ratio to pretensioned bridge girders. The test results indicated that performance in terms of load-carrying capacities, ductility, and crack patterns was improved by using high-strength concrete compared to predictions of AASHTO specifications. In addition, the prestressed concrete (PSC) specimen, in which higher percentages of debonded strands were used, showed superior load-carrying capacities, stiffness, and ductility compared to the specimen in which the number of partially debonded strands did not exceed 25% of the total number of strands. A parametric study on the relationship between concrete strength, debonding ratio, and maximum girder length was conducted. Cracking angle analysis was carried out and compared with the AASHTO specifications and RESPONSE 2000 program.