Guardrail load on top of retaining wall

[3Fan]

Hi, I am doing a retaining wall design that is retaining a parking lot of a resturant. The wall will have guardrail monuted to the top of the wall to stop cars that are parking from driving over the edge of the wall. I cannot seem to find any information on what the horizonatal load is that I would apply to the wall for this situation. When we do highway guardrail design , we use a 10K load applied at the top of the rail. That of course is for vehicles traveling at highway speeds. This design load I assume would be mush less since the vehicle is barely moving.

Any help is appreciated.

Thanks!

 

[oldrunner]

I would design the guardrail as conservative as possible. People do drive at high speeds in parking areas. Assume the rail is stop someone from committing suicide.

Just a week ago a woman apparently trying to commit suicide drove through a guard rail at Echo Summit on Highway 50 near Lake Tahoe and crashed down the slope for four or five hundred feet. It was dramatic to watch the rescue on the noon news. I understand that the lady lived.

Old people slamming on the brake but missing and slamming the accelerator.

Check with your insurance company also.

 

[Panars]

Another thing to keep in mind is that the 10 kip load is for a vehicle hitting the guardrail at an angle. The load in the parking load would be a head on impact.

 

[3Fan]

By adding that 10 K load to the wall it makes the overturning moment HUGE. Doesn't exactly help with the sliding either.

Any suggestions on how to help take that moment out of the wall? Tieback with a deadman? Move the barrier onto a sleeper slab?

Thanks,
Greg

 

[blueoak]

Are you woried about the retaining wall? This isn't a load applied across the entire length of wall.

 

[3Fan]

Was worried about the retaining wall but forgot about the railing distribution factor in AASHTO. So the 10K load will be distributed across the railing 0.8X + 5. I also feel comfortable taking that distributed load with a 2:1 distribution down to the footing level.

I think I got it under control now.

 

[BurgoEng]

What is the "X" value? thickness of wall? spacing of posts?

 

[3Fan]

X = to the point from the center of the railing to the point under investigaiton. AASHTO 3.24.5.2

 

[PEinc]

3Fan,

You didn't say what type of retaining wall you are designing. The answer to your question may depend on the wall type. CIP cantilevered wall? SRW/MSE wall? Soldier beam wall? Gabion wall? Sheet pile wall? Tiedback wall? etc.

 

[3Fan]

CIP Cantilevered. Sorry.