Tunnel frame repair - rust !

[JohnGalway]

So, unfortunately there's rust on my sheep tunnel frame, quite a bit of it on the short anchor poles coming out of the concrete wall.

Plan was to clean out/up tunnel, sheet it with tin, put in a concrete floor. But this needs addressing first.

The pics may not show it fairly but it's eaten into the tubes.

How would people address this problem?

Something came to mind, to ask an engineering shop to make a base plate with an anchor tube welded on that I can bolt into the concrete after cutting away the old anchor tubes. I'd get it galvanised.

Other constructive ideas welcome

Another question, is yhere any way to clean up rust higher up on the frame or am I looking at cutting bits out?

 

[renewablejohn]

Just angle grind off the surface rust then apply a liberal coating of grease then apply an overlap bandage like a spiral up the greased area and tie off. Then cover the bandage with more grease and finally cover with another bandage.
If you put up polytunnels again its worth wrapping the ends as above before setting the ends in concrete. I do the same process for tie down rods and it does work as I have just removed a shed base I put in over 20 years ago and the rods where still as good as the day I put them in.

 

[ewald]

How about some tube that will slip inside? Cut at ground level, weld a piece in then drill and bolt the top back on

 

[Sharpy]

Your base plate idea is sound, I would use a heavier wall thickness tube than original if I could find it.
As to the rust higher up it looks like your u bolts weren't galvanised and this has bled the galv off the tube., possibly worth tying some.zinc to that area?

 

[steveR]

I prefer the tube inside approach I have to say, and from the look of the pics, the original steel work looks to have almost eaten through?

Cut at ground level, then again higher up, giving enough room to slip the support tube inside. Fix top end with a bolt, or even a couple of Tek screws, then place a mold (a bucket, some soil pipe?) around the base and put good concrete up to just below where you cut the original tube off.

On old barns where the steel work has rotted off, I have dug down to the original base of the RSJ, welded a hefty support bar both sides of the RSJ where it has rotted off, then concreted up beyond where it rotted off at ground level. Got some I did 35 years ago still looking good. DO NOT use post mix though....

 

[Exfarmer]

I would go for a base plate drill four 20mm holes in the corners, weld some half tube about 150mm long on top which will fit snuggle around your existing pipe. Then cut down middle
weld four pieces flat as wings on the pipe . drill holes in these so they will clamp over pipe.
Then take your pieces clamp to the pipe at ground level and drill through the holes into the concrete base and fix with Rawlbolts or Chem fix
Hope this is clear. Ddid similar to a dutch barn many years ago where the stanchions had rust right through and it is still upright

 

[David1968]

I believe you're near the sea?

I'd go stainless steel for replacing the u-bolts, and any bolts used in fixing the problems at the bottom of the legs.
Even stainless steel for any sleeving pipe might be worth the expense.

 

[ewald]

I believe you're near the sea?

I'd go stainless steel for replacing the u-bolts, and any bolts used in fixing the problems at the bottom of the legs.
Even stainless steel for any sleeving pipe might be worth the expense.

Possibly worth it, but how old is it and how long do you need it for?

 

[Welderloon]

Your base plate idea is sound, I would use a heavier wall thickness tube than original if I could find it.
As to the rust higher up it looks like your u bolts weren't galvanised and this has bled the galv off the tube., possibly worth tying some.zinc to that area?

This
If replacing any thing make sure its heavier gauge, properly galvanised & any fixtures & fittings properly Galv'd electroplated or Stainless
Personally I'd opt for a bolted base plate with a drilled solid stub shaft attached then galvanised which will allow you to drop the hoop tube over & bolt through - this should last long term & make any future damaged hoop change out easier
Any mild surface corrosion will need dressed - use a proper wire brush on the grinder & some Galvafroid paint or heavy zinc based coating.
If you are near the coast then the salt onto plain mild steel will attack galv'd finishes as your U-bolts & bases confirm.

 

[TelesnaAg]

I use bitumen paint or polyurethane paint for these tasks, posts in cattle yards that are all concreted, cheap, easy to apply, do from new or close as you can.

As for repair job on yours not sure how deep rust is, but anything you put in paint with above.

You can get shrink wraps but expensive compared to paint.

Ant...

 

[AlCapone]

You want to cover the frame with tin
Will galvanise tubes be strong enough?