Best concrete mix for HEAVY gate posts?

[Nimonic]

I'm putting in a wrought iron gate to contain a damn dog. Yes, wife and kids got a pup and now it's my job to contain it.

So I'm building a pretty ambitious gate, with 4"x4"x0.120 wall steel posts. Going about 3.5' deep. Total length may be around 10ft (3 in ground, 7 out). Historically, for wooden fence posts, I've used a couple of Quickcrete bags mixed in a wheel barrel. Kinda thinking I may need a higher PSI material given the bending moment with the heavy gate. Any recommendations from the local gurus on mixes and methods?

Thanks,
Molloy

 

[Majordisorder]

I would use 5-1/2 sack.

 

[dladcock]

I don't know if this would work, but the theory is impressive. I have seen this same type of system used to set post for decks.


http://www.smooth-on.com/a144/New-Application-Video---Setting-Posts-With-Foam/article_info.html

dla

 

[Nimonic]

Have you ever heard of lining the bottom of the post hole with 6" of concrete or rocks?

 

[Toolfool]

It doesn't hurt to put crushed rock in the bottom of the hole. You can use quikrete and add a coffee cup of portland cement to each bag as you mix. A wider footing will give your post more support.

 

[Nimonic]

I bought some 5500 psi mix. The holes are dug down to solid rock (via jack hammer) so I see no need for gravel in the bottom. I'll probably just drop it in next to the string line, get it level and call it good.

 

[rancherbill]

PSI really doesn't matter.

If you are concerned with the post moving sideways make the concrete bigger. For example a post in a 6" hole might wiggle with the side loads more than a post in a 12" hole filled with concrete. There is a lot more area on the larger piece of concrete. It is also important to have concrete at the top of the hole for side loads.

 

[Leaflessshadetree]

For a heavy gate run a tensioned member or guy-wire along the fence, to the base of the next post.

 

[Bondo]

PSI really doesn't matter.

If you are concerned with the post moving sideways make the concrete bigger. For example a post in a 6" hole might wiggle with the side loads more than a post in a 12" hole filled with concrete. There is a lot more area on the larger piece of concrete. It is also important to have concrete at the top of the hole for side loads.

Ayuh,.... Exactly, ya need mass for ballast, not strength for tension,...

 

[Woody610nb]

I feel bad for the dog.

 

[SteveCh]

I feel bad for the dog.

Definitely.

 

[Nimonic]

I feel bad for the dog.

Definitely.

Why, because I won't let it run out into the street to get hit or because I used (gasp) mean words in my post?.

BTW, for the helpful posts, the holes are ~18" wide. Lots of concrete. Soil is caliche rock and clay. Pretty hard stuff. Had to use a jack hammer after getting through my 6" of top soil.

 

[Woody610nb]

A relationship between two different species, dog and man, can be one of the most rewarding experiences in life. Both, being able to show love, respect, admiration and loyalty without words takes your spirit to a higher level. I often feel sorry for people that never experience this. Your dog only wants love and comfort for you and could probably teach you some thing about sharing.

 

[Nimonic]

A relationship between two different species, dog and man, can be one of the most rewarding experiences in life. Both, being able to show love, respect, admiration and loyalty without words takes your spirit to a higher level. I often feel sorry for people that never experience this. Your dog only wants love and comfort for you and could probably teach you some thing about sharing.

You know absolutely nothing about how many dogs, cats, ferrets, flying squirrels, and other pets I have had in my nearly 50 yrs of life, nor do you know anything about how I treat them. All of my pets seem to love me, so...there is your answer. The original post was a reflection of justified frustration that my wife and kids brought home a puppy and I was stuck with with the containment issue (Hi honey, you need to build a gate and fence, now). Maybe I should have said my damned wife? Then I'd be on the hook for spouse abuse right?

If I had no compassion, or no love for animals, as you seem to infer, I would not be building a gate/fence to keep the pup out of the street.

 

[csp]

This site seems to have a knack for assuming the worst about any situation.

 

[musgofasta]

Drive some pieces of rebar into the surrounding ground from your post hole before you pour the concrete for some added leverage against the gate.

 

[theoldwizard1]

The lateral force that a post can take without deflecting is not only a function of the post's strength but also a function of the soil's strength surrounding the concrete. If the soil is soft than a bigger hole with more concrete for ballast is needed. The tendency for the unit (post + concrete) to rock or deflect may also be overcome by digging a bell shaped (bigger at bottom than at top) hole.

Finally someone has it right !

These are called Bigfoot concrete footing forms.

Make sure the "bell" is below the frost/freeze level in your area, which means you might need a longer piece of steel.

You don't say how big or how heavy the gate will be. If we are talking the size of a single car driveway, I would use 3/16 wall minimum and consider running a couple piece of rebar down the inside of the steel and then filling that with concrete.

 

[GCncsuHD]

Make sure the "bell" is below the frost/freeze level in your area, which means you might need a longer piece of steel.

He's in Austin, Tx, so I'm guessing that is what, 1/2"?

 

[texaspyro21]

He's in Austin, Tx, so I'm guessing that is what, 1/2"?

The dog's water bowl probably wouldn't freeze thicker than 1/2".

I'm a big fan of belling out the bottom after seeing how easy it was to jack out normal concrete fence pilings.

 

[Milton Shaw]

Make sure you prime/paint the post where they enter the concrete. That is where all the posts, railings that I have seen have failed. Also Inside the post unless you are capping it to keep if from filling with water and rusting out from the inside. Also a post full of water will freeze and swell up as the water has no where to go.

 

[theoldwizard1]

Make sure the "bell" is below the frost/freeze level in your area, which means you might need a longer piece of steel.

He's in Austin, Tx, so I'm guessing that is what, 1/2"?

OOppss !! I guess the original 3' depth is adequate, but that makes a "bell" even more important.

 

[rancherbill]

These are called Bigfoot concrete footing forms.

The guys problem is LATERAL load not vertical load.