Jersey Barrier Anchoring Advantage 1

LittleInch said:

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.

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

Claudia_C said:

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.

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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.

Claudia_C said:

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.

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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?

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.


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.

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.

LittleInch said:

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?

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Yes! Correct! This project resulted after the Houston Are (La Porte) fire on the Energy Transfer site.
ETC simple placed 4 jersey barriers around their site now.
I wanted to look further into what barriers to use, which would be most cost effective and which would inflict less damage to the driver. I don't know. I didn't want to simply say ok jersey barriers fine. I wanted to back up my decision I guess. I might be over thinking it.

LittleWheels said:

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.

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Will definitely look into this.

IRstuff said:

You've not said, but much depends on whether the collisions are intentional or accidental

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If you are looking at light loadings (accident, glancing) Jersey barriers will work OK without being anchored. If a little more than that, a cast 'footing' with anchors will work (just remove the organic soil and put on a gravel bed). If intentional, an actual barricade should be designed or actual designed bollards. You have to know the level of attack required.

Claudia_C said:

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.

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That's a pretty substantial load and Jersey barriers will not likely work. You have to design a barricade or bollards for specific protection. Can you check with a guardrail (highway) manufacturer/suppler?

dik said:

If you are looking at light loadings (accident, glancing) Jersey barriers will work OK without being anchored. If a little more than that, a cast 'footing' with anchors will work (just remove the organic soil and put on a gravel bed). If intentional, an actual barricade should be designed or actual designed bollards. You have to know the level of attack required.

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Actually, I might have been overestimating the impact load. I am looking at accidents, not intentional. I am posting a design done for one of our previous sites. They did not cast a footing on a gravel bed, but did pour concrete inside 4in pvc pipes. The pvc pipe goes 8ft into the ground. My initial question about anchoring came about because I wanted to do away with anchoring at all. To same money and labor time I guess. Thank you for your input.

Thank you everyone for the valuable input. I am attaching a drawing that shows the barrier that we placed at one of our sites.
The 4in PVC were embedded down into the ground about 8ft and filled with concrete, to anchor the barrier.

Claudia_C said:

The 4in PVC were embedded down into the ground about 8ft and filled with concrete,

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That won't resist much horizontal load, and even less if there is a moment. The 25M vertical will help a little.

Claudia_C said:

The 4in PVC were embedded down into the ground about 8ft and filled with concrete, to anchor the barrier.

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If you'd skipped the concrete and dropped a 3" XS steel pipe into it, you might have something that would provide at least some decent amount of resistance. As it is, the shear capacity isn't enough to significantly increase the resistance of a free barrier.

Claudia_C said:

Yes! Correct! This project resulted after the Houston Are (La Porte) fire on the Energy Transfer site.
ETC simple placed 4 jersey barriers around their site now.
I wanted to look further into what barriers to use, which would be most cost effective and which would inflict less damage to the driver. I don't know. I didn't want to simply say ok jersey barriers fine. I wanted to back up my decision I guess. I might be over thinking it.

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To be honest, that Laporte fire was not something which any normal risk assessment would have flagged as being particularly hazardous. You can't protect sites from everything and someone driving an SUV at 60 mph + across an open area of ground from the parking lot on the other side was a bit of a freak occurrence.

So that's why I've been saying you really don't want to be jumping to solutions when I don't think you've really looked at and understood what the problem is you're trying to solve. Hence you can't say its cost effective and any solid barrier is likely to do severe damage to a vehicle and occupant if you actually have anything other than a glancing collision.

Now maybe what you could do is a bit of both. Have some low level barrier - be it metal armco type or even simple jersey barriers, then around the really sensitive equipment install a bit further back some heavy duty bollards. 10" or 12" pipe 4 -6 ft into the ground filled with concrete at something like 4ft center to center spacing

Even those plastic water filled interlocking barriers would probably stop 90% of collisions / accidental wandering. They would definitely reduce any chance of injury or damage to vehicles.

But figure out your requirement first.

Like this

The utility I work for has lots of electric substations that are subject to vehicle "incursions". Some are at the edge of parking lots, some are next to highways, or on city streets. They employ everything from bollards to guardrails to cable barriers ( https://protogetic.com/our-products/vehicle-barriers/cable-barriers/ ). It all depends on the risk assessment as Littleinch noted above. The utility found out that jersey barriers weren't really a long term solution and got lots of complaints that they were ugly.

The O&M Dept seems to like the cable barriers the best as they can be temporarily removed for special access. The Engineering group also likes that the design of locating the posts is somewhat flexible when trying to avoid the underground facilities.

The risk assessments I've been involved in look at the particular location and then there is a bit of a group session where you agree is an incursion, likely, unlikely, very unlikely, not happened before or physically impossible. Then you look at consequences and rank the resulting risk accordingly.

I get that after that collision and fire at La Porte, there has been a sudden realisation that even "very unlikely" is not "never going to happen" and the consequence, especially for that unholy mix of liquified gases that were being transported, was a lot higher than maybe people understood. So then you're into the "do something now" mode and also at the same time trying not to spend any money or kill the person who accidentally drives into these barriers. but you still need to go through the process and yes, those jersey blocks of concrete would probably do the job, but are ugly, difficult to move when you need to get access and may not actually be required.

LittleInch said:

The risk assessments I've been involved in look at the particular location and then there is a bit of a group session where you agree is an incursion, likely, unlikely, very unlikely, not happened before or physically impossible. Then you look at consequences and rank the resulting risk accordingly.

I get that after that collision and fire at La Porte, there has been a sudden realisation that even "very unlikely" is not "never going to happen" and the consequence, especially for that unholy mix of liquified gases that were being transported, was a lot higher than maybe people understood. So then you're into the "do something now" mode and also at the same time trying not to spend any money or kill the person who accidentally drives into these barriers. but you still need to go through the process and yes, those jersey blocks of concrete would probably do the job, but are ugly, difficult to move when you need to get access and may not actually be required.

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I have done some "risk ranking" on my end. We have approximately over 200 above ground sites and I was able to narrow down 20 potential high-risk sites. I looked at proximity to the roadway, AADT, speed limits, population density around the sites to rank each location.
Now I'm trying to figure out what barrier system would work best. When I received the drawing of the jersey barrier with the pvc and concrete of what was previously done at one if the sites. I didn't think the concrete filled pvc would add any protection. So why even spend extra money and time doing that.
I agree I need to continue doing my research before implementing.