Jersey Barrier Anchoring Advantage 1

[Claudia_C]

Good Morning All,

I am working on a project to place jersey barriers around our above ground pipeline sites to mitigate any risk of impact due to traffic. Most of our sites are located on the side of roads in easements.
I have been doing some research and it appears that to anchor a barrier you have to anchor it to asphalt or concrete.
Has anyone ever anchored a jersey barrier to soil? How was this done and is there any advantages to doing so?

Thank you

 

[Claudia_C]

This is the key for sure. So each location needs a different solution. There are quite a few threads on this site over the years on how to build a barrier to stop everything from cars at 10 mph glancing blows to trucks travelling at 50 mph in a head on collision.

I think its AACE or maybe the different DOTs who have good standards on road barriers so no need to reinvent the wheel here.

Ok thanks! I'll check Txdot since we will be looking at our houston area sites first.

 

[BridgeSmith]

Right. I was going to assume a mid to large size SUV so about 6000lbs, travelling at 60mph, and hitting the barrier at a 30 degree angle. Typically.

A pin going into dirt won't do much against an impact that large. I'll have to look at my AASHTO Bridge Design spec to see what Test Level (TL-x) that would correspond to. The linked barrier sections might absorb that impact within the 5-7 ft deflection limit, but I don't remember off the top of my head.

 

[LittleInch]

Right. I was going to assume a mid to large size SUV so about 6000lbs, travelling at 60mph, and hitting the barrier at a 30 degree angle. Typically.

Be careful about something like that as that is a significant force / energy to absorb and deflect. Whilst some of your systems may need this level of protection, others may not or given the road layout that sort of collision verges into the impossible or extremely unlikely.

Protection for something like that will need solid pile type protection with maybe 4 to 6 ft burial in concrete. Jersey barriers almost certainly won't work, nor standard traffic barriers which are designed for glancing blows and deflect cars back onto the carriageway.

I kind of sense this whole protection issue has not been fully thought through, but given to you as a "simple" we need some protection from traffic idea, maybe as a result of that Houston fire?

 

[LittleWheels]

30 degrees is a really steep approach angle for most vehicle barriers alongside a road. Is it practical for a vehicle to approach your pipeline at 30 degrees at full speed (outside of a curve = probably, inside of a curve = unlikely)?

There are national and other codes/ guides available that assess the likelihood and consequences of vehicle impact on various infrastructure to allow engineers to select appropriate traffic barriers. The UK and Australia have done good work in this field. No doubt there are similar guides elsewhere in the world.

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/567213/Guide_to_the_RRRAP_Issue_1_rev_2.pdf

AustRoads Guide to road design Part 6 has good information on protecting critical infrastructure, as does Queensland Rail's Specification - Civil - Design and Selection of Road/Rail Interface Barriers.

 

[BridgeSmith]

Per Table 13.7.2-1 of the AASHTO LRFD Bridge Design spec., a 4500 lb pickup going 60 mph and impacting the railing at a 25 degree angle requires at least a TL-3 railing. You should refer AASHTO's NCHRP Report 350 or Manual for Assessing Safety Hardware (MASH) for criteria and configurations of barriers/railings that will meet the requirements.

I can tell you that TL-3 is what most of our highway bridge rails and temporary traffic barriers have to meet, and as I mentioned before, the deflection distance for unpinned linked barriers we have to allow is 9 feet. Pinned barriers are pinned directly into concrete. Barriers pinned into soil would be considered as unpinned.