Earth Berm for Traffic Control? Temporary TL-5 Barrier?

[Riversidean]

Currently I have been asked to look into possibly using a earth constructed berm instead of a traffic barrier on the oustide edge of a outward turning road which is at the hinge to a fairly steep slope. Researching the subject on my own I am concerned about the berm merely becoming a truck ramp for the TL-5 (Test Level 5) tractor-van trailers (based on NCHRP 350) going on the turn and the amount of space it may require to build such a berm.Does anyone know of any design standards for earthen berms used as traffic barriers? I have seen discussion of earthen berms used in mining operation manuals, but other then that everything seems to be made of casted concrete for traffic barrier devices. Is there any temporary TL-5 barrier in existence?


Suggestions Welcomed.


Thanks,
Riversidean

 

[Debaser]

The only times I've seen earth berms used to stop vehicles is at the end of run-off areas (gravel traps) where the force of impact could be expected to be relatively low, and there's space to provide a considerable mass of earth. (And where that earth berm may not be particularly compacted, i.e. it's not as 'solid' as it could be).

Placing one on the side of the carriageway (particularly on the outside of a bend) I think I'd be worried about durability, even with fairly minor strikes to the side slope.

However, there may be some earth reinforcement technology which could help in that regard. Have you sought advice from any geotechnical types?

 

[mpennengr]

Riversidean

Your situation suggests the hinge is to close to the shoulder and your last sentence suggests this would be a temporary setup. If so you may consider sacrificing shoulder width to set temporary (mechanically linked) concrete barrier backed by earth/gravel fill. A real solution is lost in the absence of the road characteristics of traffic volume, truck types and splits, lane(s) and shoulder width, cross slope or super elevation, speed. The viable solutions will differ greatly based on the aforementioned. Do not discount situations where the temporary state morphs to semi permanent.