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LRFD limits for max reinforcement dropped??

LRFD limits for max reinforcement dropped??

LRFD limits for max reinforcement dropped??

(OP)
I have a prestressed flat slab design that exceeds the older c/d limits.  

In the latest edition of the AASHTO LRFD Bridge Design specs, the check for "c/d < 0.42" has been dropped [§5.7.3.3].  The code appears to address this by applying a reduction to the phi factor when the section is over-reinforced [§5.5.4.2].

This implies the moment capacity should be reduced when the section becomes over-reinforced.

Am I interpreting this correctly?  It just seems too easy to say "forget-about-it" and skip this check.

Thanks!   RAF

RE: LRFD limits for max reinforcement dropped??

If your facts are accurate, then my conclusion is ...

OK Mr. Engineer, if you think putting this much reinforcement is the right way to go, then your going to pay a penalty since you no longer have a ductile failure mechanism.

If in your opinion, increasing the thickness and maintaining a ductile failure mode are acceptable, then by all means go ahead.

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