Could I just weld this?

[Hagatronics]

I've got a gate post that is slowly leaning back - its' moved to about 20mm off plumb over 2m over the past several years.

I know the right answer is to dig out the post and re-concrete it, maybe using a longer post in a deeper hole. But that seems like a lot of work.

It's 100x100x3mm mild steel. Could I just cut in near the base and MIG/ARC weld it back straight? It's leaning directly back so I'd cut a wedge and the weld the three cut sides.

Looking for opinions, seems too easy a solution...

 

[PugetDude]

I've got a gate post that is slowly leaning back - its' moved to about 20mm off plumb over 2m over the past several years.

I know the right answer is to dig out the post and re-concrete it, maybe using a longer post in a deeper hole. But that seems like a lot of work.

It's 100x100x3mm mild steel. Could I just cut in near the base and MIG/ARC weld it back straight?

Looking for opinions, seems too easy a solution...

No harm in trying...nothing ventured, nothing gained. You can always dig it out later in a few years if it continues to move.

edit:
If you cut the three sides and bend it back, you will probably just be able to weld it; no wedge required. A small gap (3mm or so) at the base will equate to quite a bit of movement at the top.

 

[Hot Rod Grampa]

Is there a "foot" to pick up the weight of the gate when open? Or is it a fence section? Your wedge would work but the metal may be thin there from corrosion. Won't know till you cut it open. But if it was a gate I would make an adjustable foot to jack up the end of the gate until the post was plumb then make a permanent post at the correct height. Good luck.

 

[wileycat51]

It looks like a hollow square post. How about straightening mechanically and then filling it with concrete? Ever try to bend a lally column?

 

[p_mori7]

Your concrete base for the post is not big enough (heavy enough) to off set the off-center weight of the gate.

Figure out how much the gate weighs, that will tell you how much concrete you need to pour.

 

[Kaizen]

If the base moves when gate almost closed and you lift on it the I’d say no. If base not moving give it a try or install a guy support which would be welded to post and bolted to new poured pad. Many ways to do it


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[Hagatronics]

It looks like a hollow square post. How about straightening mechanically and then filling it with concrete? Ever try to bend a lally column?

How would you bend a 100x100x3mm hollow tube installed in the ground?

 

[racingtadpole]

Cut the post off at ground level. Weld a plate on the bottom with four holes in it. Chem anchor four studs into the concrete, leave about 40mm more than you need for future adjustment. Shim with plastic builders packers and tighten down.

 

[readhead]

You can cut and reweld but you will do it again next year. There isn't enough concrete. Dig down deeper next to the existing chunk and pin and pour another piece to it.

 

[danielbuck]

Or figure out how to brace it, that's probably your best bet if you don't want to bust up concrete.

 

[mrolds88]

Cut and weld as others have said. Then make a small stand to hold the open end of the gate.

 

[benjamintmiller]

You could bend it by flame straightening it. Heat up the side you want to bend toward at the bottom with a torch, then quickly cool with water. Repeat as needed.

They straighten bridges with this method when vehicles hit them.

 

[bad_idea]

I wouldn't bother cutting and welding it. It will just continue to sag and settle. I suggest the following band aid fix:

Attach a cable to the top of the post with the other end connected to a turnbuckle connected to the bottom of the next post. Pull tension on the turnbuckle to straighten the post. I have fixed a few gates with this method. Home Depot (large hardware store here in the states) sells a kit for doing this. Years later the gates still work smooth. May have to turn the turnbuckle in a few more turns every now and then.

 

[readhead]

There is no place to brace it in the open position. With 20 years of building and installing gates I see this problem often. I would get called out to price a gate for someone who already installed the posts. Most everybody connects the post to the fence but forget that the gate has an open position also and no way to brace the post. Usually I will only take the job if I can replace the post. In the OP's case someone never considered the weight of the gate in the open position and the rest of the arc until in closes.

 

[Movin/on]

How wide is the gate in Meters? Here if a gate is too wide some installers will install a wheel/tire that will support the swinging end of the gate. If that a possibility then I'd cut a wedge and reweld. If no wheel is possible then a new concrete support.

Movin/on

 

[PugetDude]

There is no place to brace it in the open position. With 20 years of building and installing gates I see this problem often. I would get called out to price a gate for someone who already installed the posts. Most everybody connects the post to the fence but forget that the gate has an open position also and no way to brace the post. Usually I will only take the job if I can replace the post. In the OP's case someone never considered the weight of the gate in the open position and the rest of the arc until in closes.

When we had the ranch and installed heavy 16' wide pipe gates, I usually installed them with a rest on the locking post and a short post with a rest for the gate at ~90 degrees to take the weight off the gates in the open position. Never used concrete (just packed the dirt really well with a digging bar- rule was all the dirt that came out of the hole had to go back in- and we were using RR ties as hinge posts) Never had to re-set the hinge posts; they weren't seeing a load 99% of the time.

A wheel really only works if the gate post is perfectly plumb and the ground throughout the swing arc is perfectly level. Our poor old Wyoming prairie ground wasn't.

 

[readhead]

That is a good plan PugetDude and I see that a lot around here for livestock gates and some driveway gates that are operated manually. The forest service does that on some larger gates. I actually see wheels damage more gates and posts than help. I usually see this problem on gates with operators.

 

[BD1]

That's the easiest. Then add a wheel on the gate end.

 

[PugetDude]

I actually see wheels damage more gates and posts than help. I usually see this problem on gates with operators.

That's the easiest. Then add a wheel on the gate end.

Problem with a wheel on uneven ground is it applies a back and forth bending moment to the hinge posts as the wheel moves over uneven ground. Since the wheel isn't supporting the gate all the time, the weight of the wheel just adds additional downforce when the ground is lower than the wheel and then applies an upward force when the ground is higher than the wheel. This is like rocking the post back and forth, like you would do if you were trying to wiggle it loose to get it out of the ground. As it loosens, the problem gets progressively worse.

 

[readhead]

A couple of months ago I looked at a job and the guy was puzzled why the top hinge kept splitting the wood post. First thing I said was get rid of the wheel. In his mind the wheel was fixing a tilting post. He ended up doing all the suggestions himself with the help of some custom hardware fabricated by us. Funny thing was this was a real nice retired guy. I asked what he did before he retired. He was a rocket scientist. We both had a good laugh.

 

[Hagatronics]

Thanks all, some good suggestions. The driveway slopes up quite a bit so no way I could install a wheel. The 'good' news is that it's sagged so much that the gate binds on the driveway so actually ends up supporting it. It just means I can't open the gate all the way

I think I'll cut and weld the plate then bolt to the concrete with chem anchors as suggested. I should be able to build a brace into the retaining wall also to stop (or at least slow down) the continual movement from the weight of the open gate. The fence appears to stop it moving inwards (weight when gate is closed).

A job for the Christmas break I think. Summer here in Melbourne!

 

[BD1]

Problem with a wheel on uneven ground is it applies a back and forth bending moment to the hinge posts as the wheel moves over uneven ground. Since the wheel isn't supporting the gate all the time, the weight of the wheel just adds additional downforce when the ground is lower than the wheel and then applies an upward force when the ground is higher than the wheel. This is like rocking the post back and forth, like you would do if you were trying to wiggle it loose to get it out of the ground. As it loosens, the problem gets progressively worse.

There are wheels that are spring tension so they support on uneven terrain. I've installed on farm gates but in this case would have a poor appearance.
IF the other end has a tubing, a spring setup could be used inside .Plate could be welded inside tube , add spring and wheel assembly to be inside. The spring tension will move as the elevation changes.

 

[readhead]

Seems like a good idea but as the spring loads and unloads you have exactly the same problem as you started with only worse. In my early gate days I thought wheels were a great idea until I had enough call backs to know better.
Wheels do have a place in the world. On long gates over level, paved areas like parking lots they work well.

 

[bad_idea]

Please forgive the tangent, but it is related to OPs issue and it appears he has decided on a course of action. If an insufficient concrete mass in the ground around the post is the issue, then how do you calculate how much concrete you need? Is there an equation for gate size/weight? A general rule of thumb? I plan on building a fence at the new house and want to be sure to build the gates to last.

 

[PugetDude]

Please forgive the tangent, but it is related to OPs issue and it appears he has decided on a course of action. If an insufficient concrete mass in the ground around the post is the issue, then how do you calculate how much concrete you need? Is there an equation for gate size/weight? A general rule of thumb? I plan on building a fence at the new house and want to be sure to build the gates to last.

The concrete has to have sufficient mass and depth to resist the overturning moment applied by the weight and length of the gate (and to be safe, three ten-year old boys swinging on it...) Maybe one of the qualified structural engineers here on the board will jump in with the exact formula for figuring the required configuration.

 

[PugetDude]

Seems like a good idea but as the spring loads and unloads you have exactly the same problem as you started with only worse. In my early gate days I thought wheels were a great idea until I had enough call backs to know better.
Wheels do have a place in the world. On long gates over level, paved areas like parking lots they work well.

They work great on linear gates (except in snow country) but only exacerbate hinge post movement on swing gates.

 

[Kaizen]

Please forgive the tangent, but it is related to OPs issue and it appears he has decided on a course of action. If an insufficient concrete mass in the ground around the post is the issue, then how do you calculate how much concrete you need? Is there an equation for gate size/weight? A general rule of thumb? I plan on building a fence at the new house and want to be sure to build the gates to last.

Just ran into this with a gate I have to build. Mine will be 16 feet wide so two 8 foot sections. Didn’t want to bury steel in concrete so I’m trying the method they use for signs and light poles.
I sunk six one foot j bolts into concrete. The fence post will have a 1/8 or 1/2 steel plate at the bottom which will bolt to the j hooks. Probably with two nuts so I can adjust the gate. Couldn’t get any consensus in amount of concrete so I dug about a 16x16 hole three feet or so deep. My frost line is four so that was my target. Then dug a 16x24 canteliever for two support bolts. Each hole took about 1100 pounds of mix. Hope this plan works. Lol.
Rebar through out the whole thing


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[readhead]

For an 8' gate you are probably fine. The 1/2" plate would be the minimum and use 5/8"x16" anchor bolts.
On our gates a typical install would be 3/8" wall tube steel buried in a 30"x30"x48" chunk of concrete. I would consult an engineer for unique installs.

 

[frankthezapper]

I did something similar to a gatepost that had rusted off at ground level....pulled it straight and then drove hardwood tomato stakes down the inside. I think my post was only 50mm square, so 4 stakes did it. I remember (10 yrs ago??) they were a bit proud, so I had to plane them a bit... I also remember at a local steel merchant that he had a display of pieces that fitted inside each other, you could find a size that fits pretty snugly inside, get it a meter or so longer and just drive into the ground (hoping that there isn't too much concrete under the existing post) If there is break through it with a nice long crowbar...

 

[1/2 Cup]

Thanks all, some good suggestions. The driveway slopes up quite a bit so no way I could install a wheel. The 'good' news is that it's sagged so much that the gate binds on the driveway so actually ends up supporting it. It just means I can't open the gate all the way

I think I'll cut and weld the plate then bolt to the concrete with chem anchors as suggested. I should be able to build a brace into the retaining wall also to stop (or at least slow down) the continual movement from the weight of the open gate. The fence appears to stop it moving inwards (weight when gate is closed).

A job for the Christmas break I think. Summer here in Melbourne!

Hagatronics All the best with the repair.

Let us know how you get on

 

[theundermount]

could you straighten the post like others have said and then anchor the post to the retaining wall/curb beside it using L-brackets

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[Hagatronics]

could you straighten the post like others have said and then anchor the post to the retaining wall/curb beside it using L-brackets

Maybe. I actually might try putting a tow hitch around it to the back of a car and see if it will pull straight before bracing. If not, then cut and weld a plate + bracing.

 

[Rory Bellows]

Maybe. I actually might try putting a tow hitch around it to the back of a car and see if it will pull straight before bracing. If not, then cut and weld a plate + bracing.

If you have a tow hitch use a come a long so you can slowing straighten the post. A few months back I fixed a dump trailer that ripped it's hinges and was bent bad. Two come alongs and it was laser straight in 5 minutes. I spent more time figuring out how to do it than actually doing it.

Your problem will be keeping it straight once it's pulled. Maybe take a long piece of heavy flat bar or angle iron and weld to the post once straight.

 

[Rory Bellows]

Could use a few more pictures of the fence.