Usable tensile strength in undeveloped reinforcement

[Enginerdad]

I need to analyze an existing bridge deck overhang to determine its moment capacity. However, the tension bars are not hooked at the deck edge and the overhang width is too short to allow the full AASHTO required development length for the bar size. How much of the tensile capacity of the bars can I rely on in this situation? I know that according to AASHTO LRFD Eq. 5.10.8.2.1c-4, if I provide more reinforcement than required for a given moment demand, I can reduce the require development length by the ratio (Required As / Provided As). This seems to imply that tensile capacity varies linearly with development length, so I'm wondering if I have say, 75% of the development length, can I use 75% of the bar's tensile capacity?

 

[Lomarandil]

This is commonly accepted, with exceptions for certain reinforcement (shear friction is one) which specifically require full development.

Hopefully some of the other users can help me remember the other exceptions

 

[1.392DL]

That's what I do in the building world, but only down to 12". Anything less than 12" I'd use ACI 318 chapter 17 and calc the bond strength based on anchorage calcs and take the worst case of either scenario.

 

[Enginerdad]

My cantilever length is just over 2 ft, so I think I should be fine. Thanks for the input!