Allowable Tensile Stress for Service 1 for Temporary Strand Removal

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Allowable Tensile Stress for Service 1 for Temporary Strand Removal

In the 'Stress Check for SErvice I for Temp. Strand Removal (5.9.4.2.2)' section of the output report, the only allowable tensile stress considered is for a severe corrosive environment, i.e. allowable tension stress = 0.0948 sqrt(f'c). I've verified that the 'normal exposure' option is selected in both the 'Bridge Description Environmental Tab' and the 'Project' pull-down environment window. However, I don't ever see where it uses an allowable tensile stress of 0.19sqrt(f'c) as allowed by AASHTO 5.9.4.2.2-1. I was able to verify that the 0.19sqrt(f'c) is the limit indicated in the 'Project Criteria Library', but the program seems to ignore this higher limit.

Rick Brice
The exposure condition

The exposure condition doesn't have anything to do with the allowable stress at the time of temporary strand removal. The LRFD limits girder stresses at release before losses and at service after all losses. However, some bridge owners want to limit stresses during intermediate construction stages.

PGSuper supports these additional stress limitations and permits the engineer to define the allowable stress limits. In the project criteria library, on the Bridge Site 1 tab, you'll find stress limitations in the box titled "Allowable Concrete Stresses - Temporary Strand Removal Stage". These are the stress limits that will be used to evaluate the subject case.

I have confirmed, using the WSDOT WF74G project template, that the allowable tensile stress at temporary strand removal is coded to be 0.19sqrt(f'c) in the project criteria and in fact uses this stress limit is used when evaluating the stresses as evidenced in the Spec Check Report.

If you are getting a different result, please post your project file for further review.

Best regards,
Rick

Richard Brice, PE
Software Applications Engineer
WSDOT Bridge and Structures Office

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