AASHTO LRFD DECK OVERHANG VEHICLE COLLISION

[structeng24]

I am working on a bridge deck design and considering the vehicle collision for the deck overhang. The railing is post and beam and the plastic moment from the post transfered to the deck is fairly large.

I am wondering if anyone has any experience/information regarding this. I can't seem to find much or any information about post and beam railings with the collision(just parapets). Any help would be appreciated. The answer may be that additional reinforcement/deck thickness is needed compared to past designs or deck designs using parapets.

Thanks for any help.

 

[BridgeEI]

From my experience, post & beams require more reinforcement in the overhangs to get the required capacity than a parapet would. I know theres a couple of examples from a DOT but would have to get to my work computer to post a link to them.

 

[structeng24]

That would be much appreciated. I have scoured the internet and can't seem to find anything. This is also a fascia mounted rail post, which may complicate things.

 

[Qshake]

Kansas DOT does a lot of what is called corral rail which is concrete post and beam. They are also a very early proponent of LRFD. Check out their website and look for the bridge manual for examples.

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

 

[BridgeEI]

The example I have isn't quite what I thought it was and haven't been able to find the others at the moment. The second part is a post & beam but it uses adhesive anchors to attach to the bridge deck. Have you tried looking at AASHTO A13.4.2?

 

[structeng24]

Yea, Actually I've seen that example, that looked like it had to do with the anchors. I'm looking at the deck to resist the transferred moment. I've looked in AASHTO A13.4.3, although I'd like to see an example to illustrate it (I figured other people must have done this before). Also, I'm looking at a fascia mounted post instead of deck mounted, like AASHTO shows. Thanks for the help though.