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tbeaulieu 03-30-2011 08:00 PM

How to size steel cable for barn wall repair
Does anyone have any experience with jacking a barn roof/pulling the top plates in?

I'm researching the project and I haven't found any discussions about what size cable to use. I'd have no idea how much force it will take to bring the plates back in before repairing the broken mortises.

My instinct is to get the biggest I can (afford).I see 3/8" typically supports 14,400 LBS. Considering the barn's only 23'x23' and I'll be using 3 cables, I assume that's way overkill.

I guess I'd love to find someone that's actually done something like this and can speak from experience.

Thank you!

jcrack_corn 03-30-2011 10:44 PM

probably not a diy job.

you could end up with a dynamic load and be in a bad situation. dynamic load could occur if the wind blows the wrong way for instance.

i would either get a pro to raise and crib it until repair is done, then lower it, OR re-engineer in place with new structural member/supports where needed.

tbeaulieu 03-31-2011 05:14 AM

Wind? Not an issue.

tbeaulieu 03-31-2011 05:53 AM

Yes, I'm aware of that issue and it's is not my plan. Rather, steel plates and eye bolts are.

Your wording sounds almost verbatim to RIchard Lazarus' writeup.

Thank you.

Bondo 03-31-2011 10:31 AM

Ayuh,... You'll need cabling that equals the strength of whatever yer doin' the pulling with...
A 2 ton come-a-long needs atleast 2 ton cabling...

tbeaulieu 03-31-2011 10:35 AM

The real question isn't how strong does each of the indiviudal components need to be, but rather the cable strength. Everything will depend on that.

Probably won't even be using a come-a-long.

If I had done this before I'd have an idea as to the effort required and satisfaction with the cable used. I'm hoping someone's done this before and can speak to that experience.

Thank you.

tbeaulieu 04-04-2011 09:06 AM

I found a good writeup of someone correcting a bow from an almost identical setup as mine using tow straps instead of cable. Sounds good to me.

jomama45 04-04-2011 09:31 AM

I can honestly say I have no first-hand experience doing this personally, but we had worked with a pro who straightened barns for a living for many years. As I recall, he always used 1/2" cable. I know he didn't buy it, so that could be why he chose to use such a big cable. He had some connection that got him as much free/cheap cable as he wanted, as it came from a skyscraper's routine elevator maintenance.

tbeaulieu 04-04-2011 09:38 AM

That's an interesting source!

Thanks for mentioning the 1/2". It's the first concrete sizing I've heard.

I started looking into the straps. Not surprisingly, mfg claimed capacities are no where near their working capacities, so I need to research this a bit more. I plan to use straps; one to each side of the main beams that connect the walls to the center post.

At some point, someone installed rods to hold the walls to the beams, but it split anyway and bent the eyelets in the beams. I suspect they were installed to stop the spreading, which had already begun.

The more I read on this, the less mysterious and scary it becomes.

jomama45 04-04-2011 09:44 AM

It's not near as scary as some may believe. I think the most intimidating part of the whole project would stem from one's fear of heights, if that was your own case. The one thing I can caution on is don't get "greedy" in moving, pulling, or straightening of the barn's structure. It took decades for it to shift, don't try to return it to it's original state in a few days, or you'll certainly be pushing the limits of your hardware, not to mention your own safety & luck..........

tbeaulieu 04-04-2011 10:03 AM

You're right. I have no idea how long it will take to bring it back in. My neighbor is super smart about this stuff and he's done it before on his own home. In his project he let the wood "talk to him". Each morning he'd give everything a little crank until he met resistance and then stopped.

I could end up lucky and have it go really easily if my suspicions are correct in that the rod was inserted in recent history, as opposed to 100 years ago.

While heights has been a major challenge for me, I'm making progress. In this project, however, I have a loft in the barn, so most of the work will be real easy in that respect. I think I'm going to install steel plates on the outside of the beams (two per side, in addition to the one that's already in the middle) with threaded eye bolts. That will probably be the only work done on a ladder.

jomama45 04-04-2011 10:08 AM

One more thing I just remembered from years back was that he always used 18-24" sections of channel iron on the backsides of his posts for pulling. Not sure if it was critical, or if was just material that he had lying around.

kwikfishron 04-04-2011 11:08 AM

199 Attachment(s)
:thumbsup: on the channel

theaulieu, can you post a picture or two of your crooked old barn?

tbeaulieu 04-04-2011 11:25 AM

2 Attachment(s)
"crooked old barn" ... boy, that sure makes it sound crummy! ;)

kwikfishron 04-04-2011 11:40 AM

199 Attachment(s)
Nice shot of the tenon pulling out.
I was hoping to see a stand back shot of the whole thing to get a visual of what your up against.

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