Evaluation of crack control methods for end zone cracking in prestressed concrete bridge girders

Abstract

Prestressed bridge girder end cracks present problems in girder design and manufacturing. Large cracks, in particular, can impact durability, and cracks near strands may be particularly harmful due to chloride ion penetration. This paper studies various crack control methods and their impact on the tensile strains that lead to cracks at the girder end. The methods studied include varying the order in which strands were cut, changing the draped strand pattern, modifying the end-zone reinforcement pattern, debonding strands, and changing the locations of lifting hoops. Girder end behavior is simulated using finite element modeling. Vertical Y cracks are deemed the most serious cracks at the end of the bridge girders, while horizontal web cracks and inclined cracks along draped strands are found to be less serious. The authors also offer recommendations for controlling girder end cracks.