Deflection....

[shoot summ]

This is one of those learn as you go things...

I bought some great ornamental gates about a year ago, the work on them is incredible. It started a whole side yard renovation that is finally getting close to complete. In my wisdom I decided to change the way the gates were originally hung in favor of some great ball bearing hinges. They previously used a "pin" at the bottom, and a brass strap at the top.

I did some research on the steel to use for the posts. I wanted something in 2.5" as I plan to wrap the posts in wood to look like 6x6. I thought 3/16" wall was enough but now that I have the gates hung there is a fair amount of deflection that allows the gates to "sag". I can probably use some sort of connection to a post less than 4' away to resolve this, and then hide it somehow in the fence. What I wondered though is if filling the 2.5" steel post with a high PSI concrete, and embedding a 1/2 rod in it would help, or if it is a waste of time?

The posts, and fence panels on each side will match what I did on this one:

 

[Steve from Socal]

Usually there are stretchers or tie bars along the top and bottom of fence posts. The posts could also be tensioned by using a diagonal to the base of the other post.

Steve

 

[Travis E.]

Are you going to leave the chain link or change to a ornamental iron type of fence?
If you are changing to a more secure fence I would think that going from the square tubing you are hinging off of now to the other square tubing at each end could strengthen, or lessen the deflection.

 

[shoot summ]

Are you going to leave the chain link or change to a ornamental iron type of fence?
If you are changing to a more secure fence I would think that going from the square tubing you are hinging off of now to the other square tubing at each end could strengthen, or lessen the deflection.

The chain link is temporary to keep the dogs in, it will look like this, I could embed some supports across the top and bottom of the panel.

 

[Zeke]

Nice work.

I think if you make your fence frame solid with screws and attach the T&G with screws like a shear panel, it will hold the gates.

Nothing better than adjustable hinges on the gates.

 

[bczygan]

Milt is right. At the moment all you have resisting the cantilever of the gate is the cross section of the steel tube post. It ia as if I were hanging off one side of a broomstick. It is not connected by top and bottom rails to the next post. And when you do have that connection. after the wood fencing is installed, and the T&G boards are installed, the adjacent wood fence panels will resist the cantilever load from the gate panel. They will create a shear panel, as he said. Remember that the wood panels and rails need good fasteners as that is what will resist tension and compression loads. And as Milt said, adjustable hinges will allow for readjustment after things do any settling.

 

[shoot summ]

Thanks for the replies, I am hoping the wood will stiffen it up a bit. Too late for the adjustable hinges, would've been a great feature though. So do you think filling the post with concrete and a rod will help at all?

 

[Zeke]

Yes, just filling the post with the right mix will definitely stiffen it. The rebar might even work against you unless it's small.

The theory comes from the dynamics of a cigarette. Pack the tobacco more tightly and the cig becomes harder to break.

 

[jhelrey]

Ex Fence Installer. What I would do if you were a customer is I would put a piece of top rail in your chainlink fence. I would even go a step further and level out the posts and put a self tapping screw in each cup. That way, when it pulls, it would have to pull two posts, not one.

Make sense?

 

[hunter1151]

Concrete is good for compression but for deflection...............I think not, I'm sure one of the engineers on here could calculate the diameter and amount of rebar required to take the load you would put on it. If I was guessing I would say a 6 inch minimum column with 3-4 3/8 dia. rebar with rings 12 inches apart and the rebar about an inch in from the outside diameter. Just guessing

 

[shoot summ]

Yes, just filling the post with the right mix will definitely stiffen it. The rebar might even work against you unless it's small.

The theory comes from the dynamics of a cigarette. Pack the tobacco more tightly and the cig becomes harder to break.

Thanks Milt, I am going to give it a try, and omit the steel....

Ex Fence Installer. What I would do if you were a customer is I would put a piece of top rail in your chainlink fence. I would even go a step further and level out the posts and put a self tapping screw in each cup. That way, when it pulls, it would have to pull two posts, not one.

Make sense?

The chain link is temporary, it will be a wooden fence there...like in the picture...that I posted,,,(twice)...

 

[larry_g]

Another way to brace this is with an overhead arch of some kind. Extend the posts up and put a cross bar or decorative arch of some kind to hold the posts apart. Mount the bar with a threaded rod that has the post between two nuts on each side that you can use to adjust the distance between the posts.

lg
no neat sig line

 

[ForceFed70]

Personally, I dont think the posts are the problem. I think the problem is how they are secured. Are you sure its the posts bending (deflecting) or are they tilting at the base.

 

[shoot summ]

Personally, I dont think the posts are the problem. I think the problem is how they are secured. Are you sure its the posts bending (deflecting) or are they tilting at the base.

I'm 100% certain, you can see where the post starts to deflect just above the blocks, which are filled with concrete.

I welded a 12x12 3/8 plate on the bottom of the post. It is in a hole filled with concrete 12" below the 6" footing that I poured for the block wall. The 4" of concrete was poured on top of the footings. If those posts are tilting at the base I'm not sure what more I could do to keep it from happening.

The sag was initially much worse so I put my 10 ton porta power between the posts and sprung them outward, now the gate only droops about 1/2". I have a tie down running between the post and the outer post for now to keep it all in line.

 

[ForceFed70]

Ah, from the pic it looked that the posts were bolted to the top of the block wall instead of set inside.

 

[dankeenan]

Did you fill the post with concrete?

 

[dankeenan]

If you move your lower mount off the post and onto the concrete block, it will reduce the load on the base of the post. Make a new brakcet that mounts to the concrete blocks for the bottom hinge and leave your top hinge on the post where you have it.

 

[Omphaloskeptic]

Another way to brace this is with an overhead arch of some kind. Extend the posts up and put a cross bar or decorative arch of some kind to hold the posts apart. Mount the bar with a threaded rod that has the post between two nuts on each side that you can use to adjust the distance between the posts.

lg
no neat sig line

+1

 

[srmofo]

Another way to brace this is with an overhead arch of some kind. Extend the posts up and put a cross bar or decorative arch of some kind to hold the posts apart. Mount the bar with a threaded rod that has the post between two nuts on each side that you can use to adjust the distance between the posts.

lg
no neat sig line

I thought of this also, but I would make sure I could remove the arch if needed. You never know when you might have to move something tall through those gates

 

[ZRX61]

I thought of this also, but I would make sure I could remove the arch if needed. You never know when you might have to move something tall through those gates

Piece of cake to sort out:

Build the arch the correct width etc from steel... then add a small box section to the bottom of each side so it slides into the top of the posts. Then if you need extra headroom you can just remove the arch to move stuff