Crash Wall Loading

[2jdevine]

I have been tasked with designing a wall to prevent a tanker truck from sliding off the back of a unloading pad. The pad and the wall will be separate structures.
The design criteria is for a 80k truck going 10 mph and losing control due to icy conditions.
I was looking at using AASHTO table a13.2-1 for the impact force, however this is based on a 80k truck moving at 50mph.
My first thought is I could conservatively scale the 175k load by 1/5 (knowing that the actual force should be based on the velocity squared and not linear).
Is this a reasonable approach? or does anyone more familiar with the AASHTO code know of a better approach?
Thanks for any input.
-JD

 

[LOKSTR]

You need to calculate your loading for barrier based on vehicle speed and mass, if you are not able to use any of test level barriers (TL-1 to TL-6) as per AASHTO.

Following attached article may be helpful.

 

[LOKSTR]

Attached file

http://files.engineering.com/getfil...f4-a8881e5626d1&file=vehiclebarrierdesign.pdf

 

[2jdevine]

Thanks for the reply and the article.
I actually calculated the force based on the mass and deceleration. However, this lead to a excessively large force, i.e. more than what AASHTO has for the 50 mph case.
I am sure this due to the physics equations not accounting for the large amounts of energy removed from the system due to crushing of the bumper, cracking the concrete etc.
Any other thoughts?

 

[ztengguy]

Can you design for the AASHTO loading and see what you get....Im sure a 12" wall would work, and thats not too difficult/expensive to build.

 

[LOKSTR]

2jdevine,

See the attached article for calculating the impact force on a parking garage barrier. You can use the same method for your case of truck weight and speed considering zero deflection of your barrier after impact.