Fence Posts and Guardrail Embedded In Concrete

Schedule 40 pipe comes in standard lengths of 21 feet. That implies a one foot embed in the concrete, not even close to enough.

Current design around here is multiple 3/4" (or so) threaded rod poured in a concrete pile. The pipe would then be attached to a flange, suspended and sandwiched on the rod with heavy nuts. This allows for future leveling if needed.

This fence...

Horizontal members are tensioned wire, welded (maybe more pipe), or some combination? Something else; wood or woven wire maybe?

Are these posts in a straight line, or an arc/curved shape? What size pipe?

WJMFIRE has a valid observation: one foot of embed seems insufficient.

20' tall fence? Are you in Jurassic Park? What is the diameter of the posts? On a 20' post height you want 30% in ground, that would be 7'....The width of the hole for an 8" fence post would be about 40"..

Thanks for the responses. Its a 20'-0" chainlink fence with 8" Schedule 40 posts and 2" schedule forty horizontal bars. If it was built as shown on the drawings, there is 2'-0" embed into the concrete footings.

You could use a pipe sleeve embedded in the concrete foundation. Since you have 8-inch dia. Sch. 40 steel pipe uprights (O.D.=8.625"), you would need at least a 10-inch dia. Sch. 140 steel pipe sleeve. That's pretty massive, and most likely not readably available.

You're better served with a fully welded steel baseplate featuring steel gusset plates to provide fixity at the base of the uprights. Anchor bolt size and embedment length requirements pursuant to structural design calculations: shear and tensile (prying) forces are involved.......but you have not provided any information in that regard how this high fence is loaded.

A VERY BIG CONCERN: Some initial concerns of mine......Why is the concrete "significantly understrength"? And what is your actual role in this fence construction? Owner, Engineer of Record, or Contractor? Is construction under contract? And why isn't this deficiency being corrected pursuant to any Contract Documents if they exist? Is this project Bonded?

We also need more information in regard to the concrete foundation and soil conditions: it's overall dimensions, reinforcement if any, concrete compressive strengths (test method?), method of construction, in-situ soil conditions & groundwater info, and backfill conditions....and soil compaction test results and methodology used.

Agreed...

... or some more pertinent information.

I like this design...

Its pretty simple really. Fence and footing already exist at a baseball field. The primary purpose is to keep baseballs and teenagers away from a water treatment plant. The 28 day test for the footings came in under strength. The civil engineer who designed the thing no longer works for my company but it looks as though they threw together some standard fence details. I'm not the engineer of record just the guy who got stuck fixing it.

Its a pretty typical installation. The Fence post is embedded 2'-6" into a concrete footing. I'm just looking for some way to figure out if the post make break out of the concrete other than, "this is the way we've always done it" which seem to be how they are typically designed.

So, the concrete failed the compression test. It needs to be replaced.

You have an opportunity to improve on the design. Around these parts, stickin' a pipe into the wet concrete is suitable for a backyard fence at your house, but for this application I would give the advice from CaptMoosie in #5 some serious thought.

There is a reason nobody wants to simply give you the answer to your original question: "...a good design guide for installations of structural members embedded directly into concrete instead of a base plate..." is not good practice, even if "this is the way we've always done it".

I found this paper using Google showing some test results of embedded hollow sections performed in Munich, Germany. Don't know if it will be of much help.

It seems to me the columns are a bit on the limber side for a 20' high fence but that is not the question you asked. The concrete footing would have to be appropriately reinforced to prevent failure of the concrete from the prying action.

Incidentally, I have a question unrelated to the problem. Why is this particular thread stretched out over two pages in width? Is anyone else experiencing the same thing?

Yeah, when SolarEagle pasted in the dinosaur pic he didn't manually resize it.

The display screen adjusts for these oversize images. I think a mod can fix it... don't know why they haven't.

Thanks, Doorman. Looks like someone did fix it. All is normal now.