Proposed evaluation and repair procedures for precast, prestressed concrete girders with end-zone cracking

摘要

>Precast, prestressed concrete bridge girders are widely used in the United States. Longitudinal web cracks, often called end-zone cracks, at the ends of pretensioned concrete girders are commonly observed at the timeof strand detensioning. End-zone cracks differ from flexural cracks in conventionally reinforced beams and slabs and from tensile cracks in water storage structures. In practice, there is no consistent understanding of the effect of end-zone cracking on the strength and durability of the girders. Thus, the decisions made by bridge owners vary from doing nothing to total rejection of the girders. There is no consensus among owners as to acceptable crack widths. This paper gives a user’s manual for acceptance and repair of web end cracking and details of end-zone reinforcement that will minimize the number and width of end-zone cracks. The user’s manual and reinforcement details were developed in the NCHRP 18-14 report 654.