impact barrier loading

[Skicat]

I'm trying to find within the 2,000+ pages of the easy to read 4th edition of the AASHTO LRFD Bridge Design Specifications, where to find the design procedure for vehicular impact loading for a bridge impact barrier (to protect an abutment). Thank you.

 

[bridgebuster]

Can you put up a guardrail?

If it's a concrete abutment nothing is going to happen to it if it's hit. Could you be more specific what you want to do?

 

[Qshake]

Many times you are required to place a barrier (read deflector) in front of a hazard such as wall type abutment near the roadway (especially with inadequate shoulders).

I've seen many single face jersey barriers used for this.

Guard rail is better when the hazard is further away.

Regards,
Qshake

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

 

[Skicat]

We are designing a barrier wall (42" tall approximately) to protect the connection of the main bridge beams to the abutment. I agree that an abutment could withstand an impact, but it's the connection of the beam to the abutment that we need to protect. So, I'm trying to find info on impact loading to design my wall. Thanks for your help.

 

[miecz]

Back in the 3rd edition (my latest), this info was contained in the Appendix to Section 13: Railings. Is that Appendix no longer there?

 

[bridgebuster]

Are you designing a cheek wall at the ends of the bridge seat? I'm trying to visualize how a vehicle could hit the bridgeseat.

 

[Qshake]

The old AASHTO vehicle collision load was 10K. This was in the very first or second chapter which describes overall features and railing requirements.

It may even be in a footnote.

It's in an odd place no matter what. It's not with the loads.


Regards,
Qshake

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

 

[Skicat]

I found it in chapter 13. It is considered a railing and they have various impact loads based on vehicle speed, etc. Thanks for pointing me in the right direction.

 

[71corvette]

Not entirely sure what you're trying to protect here, but if you're putting a line of barrier in front of a bridge abutment be sure to place the barrer far enough away from the element to account for vehicle roll. If a tractor trailer truck hits the barrier, the truck will 'lean' in toward the back side of the barrier and could potentially clip the abutment with the top corner of the truck.

Just food for thought.
Tim