Ballasted fence post

[ChangeOrder]

I am creating a fence post concrete foundation that sits on grade. Fence is chainlink with 6ft height and 10 ft post spacing around a construction site. Fence is permanent, but no excavation is allowed (landfill). I have applied a wind load and a 200 lbs point load at top of post. Questions:
1) What loads should i apply to the fence post?
2) should the fence posts be bolted or grouted into foundation?
3) Any advise is appreciated.
4) What reinforcement should be used?
5) Is there a precast option?

Through my analysis, i am getting a 2.5x2.5x1.5 foundation. I am using IBC 2018 and asce 7-16.

 

[dik]

I haven't checked this recently, but it may help... just revised the cover page to bring it up to date. Whenever I access an old SMath, I bring the cover up to current template. The next time I use it, I'll do a detailed check.

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1667356141/tips/Chainlink_Fence_o5ocbn.pdf[/url]

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/raw/upload/v1667356142/tips/Chainlink_Fence_lnkjud.sm[/url]

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1667356373/tips/CLFMI-Product-Manual-revised-March-2017-1_zt8qww.pdf[/url]

That's the one referenced in the SMath program; I'll add the document to the reference documents in the program. A 2'x3' pad may be better, or maybe 1'-6x 3' will work.

https://chainlinkinfo.org/clfmi-product-manual-2017-editions/

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[XR250]

Is 200lb a legit load? I thought that only applied to guardrails.

 

[Enginerdad]

The wind design load on chain link fence prescribed by AASHTO is 15 psf, and it's not applied concurrently with the live load. As you mentioned, 200 lb point load is the guard rail requirement, but a security fence doesn't necessarily need to to meet guardrail requirements. Additionally, again in AASHTO, the maximum height the post load needs to be applied at is 5 ft, regardless of whether the barrier is higher than that. It would be conservatively safe to use the guardrail load requirements, but I think maybe overkill. Perhaps just using the wind load would be reasonable

 

[XR250]

If the spacing of the 200lb load is 10 ft, wind load should control.

 

[hokie66]

Detailing will be different than usual. With the footing sitting at ground level, how does the chainlink work at the bottom for that 18" gap?

 

[bridgebuster]

The gap could be closed by cutting the fabric around the footings, although the cutting could mess up the fabric. I've seen it done to close short gaps ~2". Add a bottom tension wire and tie it to eye bolts grouted into the footing. Another way, to avoid the cut outs is to put the tension bars in line with the edges of the footing, then add fabric across the post to close the gap, but it also requires custom made tension bands.