Carpentry/Engineering Question

I don't have any photos of the finished project yet (it's now finished). But do you all think 3 trusses will have any problem supporting the guy wire anchor for my power line. I don't have a photo of the power line but I have a similar photo (length will be close to same) check out the following photos. The power line probably spans a few feet shorter than the length to the utility pole in the photo. The 3 by 3 beam spans three trusses right where the water spot is in the photo and the galvanized bolt has been cut shorter as well. The center truss is not actually "clamped" it just surrounds the beam with about a millimeter to spare on top (I figure this reduces stress). On the two side trusses there are is a grade 8 bolt smaller than a bic pen to basically just keep the beam from dropping down or sliding up or down the truss. Not really load bearing. What you all think?

 

How long is the power line??

 

I few feet short than all the way to the utility pole that is pictured.

 

I moved one that was 75 ft. to pole, but put 4x4 on under side of 4 trusses, did not move when power co put back up. I think you are ok up to 60 or 70 ft. Jim

 

How much cable is going from the your metal pole to the mail utility pole? It looks like what you've done will be adequate but it's hard saying not knowing what kind of load is really on that guy wire. With the 3 trusses being gussetted at the top and bottom it should be fine. Why are you re-supporting the guy wire, seems like something the utility company should be doing.

 

It's after the meter so maybe it's my responsibility? The old home owner and previous roofers before I owned the house kept trying to screw and eyelet screw straight into the truss and it would always pull out so I figured this would work

 

Did each of the four trusses provide lateral support too?

 

I would have put the metal plate on the back side of the 4x4 and run the eyelet through the 4x4, using the plate as a big washer, no way for it to pull out. Now you're relying on that weld holding and also your attachment to the 4x4. How are you attaching the plate to the 4x4, lag bolts? Also, make sure you flash that well. Grace Ice and Water Shield is good stuff as a base, it heals around nails and aheres directly to the sheathing. It's good stuff, I did my whole back roof with this (under the shingles of course).

 

Underground power line.

Problem solved.

That was easy.

Haha j/k. What you've done looks sufficient. There's no such thing as too much support. I would just make sure the eyelet is all the way through with a washer and bolt rather than threaded into the wood, which it looks like you've already done that.

 

I'll have to get you all photos later today. My welds will hold. The only thing coming up thought the roof is the eyelet bolt. I'm not worried about too much support. I'm worried that maybe it isn't supported enough and I could damage my roof by breaking a truss or something.

 

Yes... Jim

 

There is a slight hole where the old eyelet bolts ripped up a very small hole in the plywood that makes my roof. No concern about the hole but that is also where my metal plate fills the void and works well. So like I said in the end nothing is exposed except the eyelet bolt.

 

Only if they are correctly brace to resist rotational forces .

 

OP , have you already swung the wire over to your new mounting system ?

 

Yes. I am just concerned about the stress over a long period of time. Nothing budged the slightest bit except the 2400 lb bolt appears to have bent slightly. The mounting plate and nothing else moved a bit.

 

Just to clarify , your new post is mounted to the last truss of the set , and the force exerted by the wire is sideways to the orientation of the truss .

Correct ?

 

There is no new post. Just new anchor. And it is not the last truss. And yes the force by the wire is sideways to the orientation of the truss.

 

My first thought was crap, I wouldn't want all that power line sagging its way across my backyard !
Next time think underground as stated previously.

So you're going to guywire down to that lower roof ?
(for the best effect you want the guywire exactly opposite the direction of the power line)
Looks like the weatherhead has some strain on it.

Grabbing those 3 trusses should be OK but it looks you have site-built trusses. Are those little plywood gussets nailed off properly ?
You could go with a full gusset (just in the guywire load area) from top chord to bottom chord on the three trusses taking the uplift load.

At first glance and not being able to see the alignment from your pics, my instinct would have been to strengthen the upper roof's varge rafter and brace the weatherhead to that. No roof penetration that way.
But I can't see how things align.

The idea given that your steel plate should be on the far side of the 4x4 is a good one.
Avoid garden-variety lags like the plague. They are soft and prone to pull-out under dynamic loading.
Dynamic loading would be what will happen when that power line gets to swinging in a wind storm.

If you have to go with a lag-type fastener, the only thing acceptable for a structural app is a Simpson SDS screw or similar.

 

I bought the house and was simply fixing some things up. I spent a lot of time fabing this up. The house has been up since 1984 or somewhere around there and going after the expense of underground power lines might be out of my budget. Sounds like quite a project too.

 

If there is little to no cross bracing in the trusses , I would add some bracing to counter any rotation of the truss in the direction of the wire .

The most effective is if you can brace the truss that is carrying the wire connection as close to the connection as possible , down to the exterior wall .

You probably won't have an issue , but during a high wind event or if a tree strikes the utility wire further upstream , you can get a significant pulling force on the wire and connection .

Extra , possibly overkill , blocking and bracing now may save you some grief later .