Slab Overhang design

[everestking]

I am designing slab overhang for negative moment due to vehicle collision for post and beam railings using LRFD. For the design Case 1, I calculated the moment and thrust on the base of the post using value from LRFD Table A13.2-1, for TL-4 for transverse force. Now the problem is it requires big amount of reinforcement which is ridiculously large and does not seem practical. Am I doing something wrong?

Any help appreciated.
Thanks

 

[miecz]

That moment is a problem. I've only resisted it with concrete barriers with a fairly wide distribution. I can't imagine resisting that moment from a post. Can you switch to a solid barrier?

 

[everestking]

Client want to use the post and beam railings so I guess just design it using high reinforcing is the only alternative.

 

[crossframe]

Are you using the plastic moment capacity of a single post, per AASHTO LRFD Eq. A13.4.3.1-1? Spread out over the design section shown in Fig. A13.4.3.1-1?

With 8" nominal decks (slightly thicker on overhang due to haunch) we typically end up with #6 @ 6" for reinforcing, adding additional overhang bars as necessary.