Memorandum

TO:	All Design Section Staff
FROM:	J. Kapur
DATE:	June 18, 2001
SUBJECT:	Pretensioned Anchorage Zones

The vertical reinforcement for the bursting resistance of the anchorage zones in the end of pretensioned girders as specified in the AASHTO-LRFD Bridge Design Specifications article 5.10.10.1 shall be uniformly distributed within the distance h/4 from end of the girder, where “h” is the overall depth of precast member.

Background:

The distribution length of h/5 for the vertical in the end of pretensioned girders as specified in the AASHTO-LRFD article 5.10.10.1 is overly conservative and results in impractical spacing of vertical reinforcing at the end of pretensioned girders, particularly for longer spans prestressed girders where higher prestressing forces are required. The distribution zone of h/4 in accordance with the AASHTO Standard Specifications Article 9.22.1 has been successfully used for many years. The AASHTO Subcommittee on Concrete Bridges in their May 2001 meeting in Seattle approved the above modification to the AASHTO-LRFD Bridge Design Specifications article 5.10.10.1.

If you have any questions regarding this design issue, please contact Bijan Khaleghi at 705-7181.

JK:dsb

             cc:        J. A. Weigel, Bridge and Structures - 47340
                        E. H. Henley, Bridge and Structures - 47340
                        H. L. Coffman, Bridge Preservation - 47341
                        F. Higgins, Bridge and Structures - 47340
                        R. Lewis, Construction - 47354
                        Z. Fahoum, Bridge and Structures – 47340