bollard design

[ajk1]

Need to design a couple of bollards to replace existing corroded away bollards that are at the roll-up doors of a police station. They are on an existing concrete slab. Is there anywhere that I can find a standard bollard design detail for this, or do I have to design it myself? There must be someone who has seen a well thought out typical detail.
I would think that would comprise a 42" high minimum (60" if visibility is a concern), minimum 6.5" O.D. minimum schedule 40 steel pipe, galvanized, filled with 35 MPa concrete, base plate of appropriate thickness welded with appropriate weld size, and 4 Hilti galvanized or s/s adhesive anchors of appropriate diameter. Painted yellow (after treating the galvanized surface appropriately so paint will adhere) for best visibility. Any detail that anyone can refer me too?

 

[TehMightyEngineer]

The real issue is whether you need these to prevent entry or to be reusable after an impact. Otherwise, if it's simply a barrier to prevent a vehicle from damaging a more expensive finish or to protect pedestrians then I'd use a steel pipe embedded in a mass of concrete, fill the pipe with concrete, and paint it to prevent corrosion. Protective covers can be purchased that have architectural detailing or to provide reflective bands around the top for high visibility. These will stop pretty much any moderate sized impact and are easy to make.

If you must use a baseplate with post installed anchor bolts then that would be the area to design. I'd use something like a 20 kip impact or the force to cause yielding in the concrete filled pipe, whichever was lower, and size your anchor bolts to resist that moment and shear. I'd size the bolts so steel yielding controlled that way you can dissipate the impact forces using inelastic distortion. But, I'd only do this if for some reason digging into the ground wasn't permitted. I'd use a precast bollard before I'd try to anchor it using post installed anchor bolts.

Professional and Structural Engineer (ME, NH)
American Concrete Industries

http://www.americanconcrete.com

 

[Debaser]

I don't want to derail the thread, but I often see US engineers designing from scratch what would (certainly in the UK and I assume Europe) be stock items of street furniture (bollards, sign posts, etc.). Is there a reason off the shelf items appear to be less well used?

E.g. example of anti ram-raid bollards.

http://www.industrialsuppliesco.co.uk/details/Bollard-G

http://www.barriersdirect.co.uk/bol...bollard-219-273mm-diameter-anti-ram-raid-p608

 

[TehMightyEngineer]

Debaser: My guess is it's the contractors pressuring to build items in-house or find cheaper alternatives to a manufactured item. For example, our precast steel pipe bollards are about $400 for a standard bollard + $80 for a plastic high visibility sleeve + delivery. If you need a bunch of them or need them quickly then we'll be the place to go. That said, if an engineer called out our bollards and the contractor had some steel pipe laying around I'm sure they could save some money making it themselves and then all the money goes to their workers instead of us.

Just a guess, though. I personally try to specify off-the-shelf items whenever I can assuming it's not a huge cost difference.

Professional and Structural Engineer (ME, NH)
American Concrete Industries

http://www.americanconcrete.com

 

[JedClampett]

Most public entities have standard desings for this type item. For example, doing a Google search on "bollard Design public works" hit

http://tillamookor.gov/wp-content/u...k-Public-Works-Design-Standards-Dec-2014.pdf.

On sheet 238 there's a removable bollard and on sheet 295 there's a permanent, and pretty beefy, one.

 

[KootK]

I would think that would comprise a 42" high minimum (60" if visibility is a concern), minimum 6.5" O.D. minimum schedule 40 steel pipe, galvanized, filled with 35 MPa concrete, base plate of appropriate thickness welded with appropriate weld size, and 4 Hilti galvanized or s/s adhesive anchors of appropriate diameter. Painted yellow (after treating the galvanized surface appropriately so paint will adhere) for best visibility. Any detail that anyone can refer me too?

Found this bad boy kicking around the digital archives. Almost verbatim. I had nothing to do with this detail's creation.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[MikeHalloran]

<tangent>
There's often a similar structure on a boat, also called a bollard.
It usually has a crossbar, less often a rounded flange, to keep a hawser from slipping off the top.

On tugboats, they're made of really big steel tubing or pipe with really thick walls, and securely welded to the boat's structure from deck to keel.

My guys down at the marine exhaust shop designed and sold a really pretty one to a yacht captain, with a 3" dia barrel and a 1-1/2" dia cross bar, both made from our best stainless steel tube, #12 gage, beautifully welded to a nice square flange and mirror polished.

After it was shipped and installed, they asked me to give it a load rating.
I figured the tubing would fold at 3 kips or so,
and asked them not to sell any more bollards.

It should do well holding the dinghy painter...
</tangent>

Mike Halloran
Pembroke Pines, FL, USA

 

[BUGGAR]

Breakaway bollards are required in some jurisdictions for safety reasons.