Gate post help

[FenceWelder]

Good evening all. I'm going to be setting posts for my driveway gate and need some help.

The gate will be 16' that I'm planning on less than 500#. Built out of 3x3x0.25 for the hinge support 2x2x0.85 everywhere else.

The soil is eastern fresno county heavy black clay that swells in the winter and gets 1" cracks in the summer.

The post will be 6x6x0.25. I'm stuck on how deep the post should go. I'm thinking 30" hole 6'deep set in concrete. Would this work?

Thank you for the help.

[zipzit]

Built out of 3x3x0.25 for the hinge support 2x2x0.85 everywhere else.

Something odd on that 0.85 gauge. That's nearly solid 2" bar stock.

[FenceWelder]

Mistyped 0.085

[Country Metals]

I use to be a member of NOMMA like 10 years ago when I was doing a lot of wrought iron railings. Gate posts was a huge topic on their forums.

If your building a 16'long single leaf gate, that's a long load. It will need a much bigger support base. I would dig a big 4'x 4' hole 3' deep and put a 6" I beam in an X formation and bury it in a foot thick of concrete. This doesn't include your 6x6 30" deep either. The common thing everyone use to say was concrete was cheap insurance.

A 30" deep sonotube will not be enough to hold up to opening and closing and people hanging on it possibly and snow and rain and soft soil and freeze heave etc...

As a side note, you want the hinge tube the strongest, but the bottom tube takes all the horizontal load so it needs to be almost as strong as the hinge tube. 3x2 x 1/8 or 3/16 is a common bottom tube. Your design must also include some type of strap from the top of the hinge tube to the bottom corner of the opposite corner. It doesn't have to be an ugly bar but it needs the support of one.

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[lotechman]

I had a situation where I needed the fence post right on the property line and part of the neighbor fence. That limited depth and size of concrete for anchor. What I decided to do was weld up sort of a spider below ground level. The post had a tube running out across the driveway a foot below ground and another running parallel to the fence line also a foot underground. Just like the gate cantilevered out into the air I had arms cantilevered out underground.

[FenceWelder]

Thanks for the help. I think I am going to change my plan after doing more research and reading what you guys said.

First I'm going to change this to biparting 10' gates. This will give me wider opening and less stress on each post.

Additionally I am going to do a grade beam along with an overhead beam at 14' high. To support the gates in the open position I will add 5' outriggers parallel to the open position.

My goal is with the dynamic nature of my clay soil that this thing never moves.

Pretty cool website I found www.gateinfo.org

Thanks for the help

[William McCormick]

Good evening all. I'm going to be setting posts for my driveway gate and need some help.

The gate will be 16' that I'm planning on less than 500#. Built out of 3x3x0.25 for the hinge support 2x2x0.85 everywhere else.

The soil is eastern fresno county heavy black clay that swells in the winter and gets 1" cracks in the summer.

The post will be 6x6x0.25. I'm stuck on how deep the post should go. I'm thinking 30" hole 6'deep set in concrete. Would this work?

Thank you for the help.

That is probably plenty deep but you need a conical pour and at least one and a half yards of cement to take up the vibration, from my experience. The wedge shape or conical pour acts like a tapper on a drill press. The cone does does not sink.

Sincerely,

William McCormick

[WedingSir]

Wouldn’t a round post be better than a square post for the main gate post? I used a 2x3 1/4 and have sag from a 6’ gate with 1x6 cedar screwed into the frame. Sphere’s /cylinder won’t flex as much as square in steel??

[farmersammm]

I build extremely light gates...…….for a reason.

Bearing specs on soil vary...….not only the perfect bearing capacity, but the wet capacity.

14ga 16' gate...……..with mondo support.



(Gates don't keep people out, dogs 'n guns keep people out) (And cows will push, or bump a gate, and if it resists, will leave it alone)

Anyways, take a look at the structure...………….. .25 wall pipe, with kickers. It takes a lot to keep stuff level year after year. Why?? Weather, and expansive soil. That little puny, maybe 100# gate, exerts tremendous pressure on the support.

Get your software out, punch a few keys...……….then double it.

I don't build a gate to resist pressure (this is a livestock gate). I build it to flex, and distort if push comes to shove. Bent gate is easy to straighten, fubar'd gate post is a different story. I'd rather smoogie the gate.

Depth of support...……...figure optimal, then go deeper.

If your design, and the owners, can stand it, use a dead man for the kickers. Failure proof. You gotta resist pullout.

And if the gate is for the 1% crowd...…….doesn't matter how strong it is...……...folks with nuthin' on their dinner plate dinna care about gates. They gonna climb it, and gut the owner of the palatial estate, then raid his/her fridge.

[FenceWelder]

I build extremely light gates...…….for a reason.

Bearing specs on soil vary...….not only the perfect bearing capacity, but the wet capacity.

14ga 16' gate...……..with mondo support.



(Gates don't keep people out, dogs 'n guns keep people out) (And cows will push, or bump a gate, and if it resists, will leave it alone)

Anyways, take a look at the structure...………….. .25 wall pipe, with kickers. It takes a lot to keep stuff level year after year. Why?? Weather, and expansive soil. That little puny, maybe 100# gate, exerts tremendous pressure on the support.

Get your software out, punch a few keys...……….then double it.

I don't build a gate to resist pressure (this is a livestock gate). I build it to flex, and distort if push comes to shove. Bent gate is easy to straighten, fubar'd gate post is a different story. I'd rather smoogie the gate.

Depth of support...……...figure optimal, then go deeper.

If your design, and the owners, can stand it, use a dead man for the kickers. Failure proof. You gotta resist pullout.

And if the gate is for the 1% crowd...…….doesn't matter how strong it is...……...folks with nuthin' on their dinner plate dinna care about gates. They gonna climb it, and gut the owner of the palatial estate, then raid his/her fridge.

After reading your post I've found you didn't contribute anything other than Paranoia and a bunch "euphemisms" that didn't answer my question.

[SlowBlues]

The grade beam and splitting the span is a wise choice and good insurance against much going wrong, imo the overhead beam is not needed but definitely adds support and can be made to look really classy. I'd do the outriggers in both directions as wind load and soil changes can loosen things up on both sides, and a even the nicest fence/gate looks bad if leaning/sagging. Having a gate that bends before the supports can be something to consider if it's likely to take some abuse.

[Drilldo]

My gate is 16’ long made out out 2” square tube. 14ga I think. It has an electric opener and gets opened and closed a dozen times a day. The gate post is 6” oilfield pipe maybe 1/4” wall. It is set 6’ in the ground in an 18” hole. There is an overhead and pipe fence welded to the hinge post nearly perpendicular to the gate in the closed position. It hasn’t moved or wobbled the slightest in 9 years.

[William McCormick]

My gate is 16’ long made out out 2” square tube. 14ga I think. It has an electric opener and gets opened and closed a dozen times a day. The gate post is 6” oilfield pipe maybe 1/4” wall. It is set 6’ in the ground in an 18” hole. There is an overhead and pipe fence welded to the hinge post nearly perpendicular to the gate in the closed position. It hasn’t moved or wobbled the slightest in 9 years.

Going down six feet helps a lot, ground density increases the further down you go. You used under a half a yard of cement, but because you went down six feet, it is plenty strong. We usually do not go down that deep because it is hard to dig six feet deep with surrounding structures. So we use a yard of cement and dig a three-foot hole four feet deep.

Sincerely,

William McCormick