Improve this A-Frame tree prop design

[NickfromWI]

What do you think? Let's assume the size of the tree doesn't matter because the strength of the posts are sufficient for the expected load.



Tree is on very steep hill.


love
nick

 

[treebilly]

Top bolt is going to be the weakest link. It will receive the most pressure.

 

[flushcut]

I would make it so there is a thru bolt on top attaching it to the tree.

My FIL design and yours as well will damage the bark over time. You can see three different prop locations.

 

[flushcut]

How close is the tree to the ocean? Is are there any salt spray/corrosion concerns if so and the tree is projected to be there a long while stainless steel might be a better option tho $$$$$.

 

[Pelorus]

Guy cables attached to the uphill side of the tree would be less obtrusive and less costly......if space allows that option.

 

[Raj]

I've always pondered a threaded rod with bracket assembly, be it vertical or horizontal. That way the supporting column assembly can be 'generic' or simple, and the attachment to the tree would be custom.

 

[NickfromWI]

Guy cables won't work because the tree grows almost horizontally out over the hill.

The way I typically support treats from below is as per recommended by the BMP on cabling/propping

Here's one I installed last week.





But because this tree is so long since been duly, I expect a lot of side to side movement in the wind. I want to have that A-frame lateral support. I can't figure out how to attach the top bolt into two legs. Keeping in mind that it needs to be able to be installed on site with very rudimentary carpentry tools available.

As far as the ocean is concerned, it basically overhangs of the Pacific! It's on a hillside not far from the beach. Here is their view from standing next to the pine.



Good to call on recommending stainless steel. I will make sure to use that


love
nick

 

[DMc]

Nick, use the tree itself as the top attachment of the A frame using the 4x4s like you normally do or at least as you pictured.

 

[Limbrat]

Where's Jomo when you need him?
If you're using 4x4s Nick a 4x post half base on the inside of each timber where your through bolt goes through will increase your strength there to a degree. Use another on the outside or the biggest flat washer you can find. I don't know if they come in stainless though.

 

[NickfromWI]

DMc- not quite sure what you mean. Make us a sketch!

Raj- there is a somewhat similar sketch suggested in the BMP. I'll post it later. They have the cradle overhead, though.

I've got a neat hardware store local that has a huge selection of stainless nuts, bolts, etc. should be no prob getting the parts.


love
nick

 

[Burnham]

Not to rain on the parade, but I will point out that, especially in a marine environment, stainless steel is not corrosion proof, just somewhat resistant. And when corrosion begins, it usually proceeds at a stupendous rate, far faster that mild steel. So plan on not only regular inspections, but also pre-emptive replacement, BEFORE it looks like the time to do so has arrived.

Or perhaps go with mild steel and size up to allow for future degradation.

 

[NickfromWI]

Clever thinking. I would've went with ½" bolts. No reason not to go with ¾". It doesn't make the install any more challenging.

What about this at the top- a horizontal piece and I ise a screw plate to connect the top three pieces together ...

(Pardon the crude drawing)




love
nick

 

[Limbrat]

Mr. B, as long as all the hardware is stainless, it will far outlast us and the next generation. In dealing with boats and trailers in saltwater all my life it's the dissimilar metals that cause accelerated corrosion. I've removed 20 year old 1/2" and 5/8" stainless bolts from saltwater docks made of pressure treated lumber that look brand new.

 

[Burnham]

Fair enough. Thanks, Ray.

 

[SouthSoundTree-]

Much better, Nick, IMO.

I'd overlap all three joints with one plate, on both sides.

 

[treelooker]

Can you install concrete anchor so close to the trunk without massive root damage?

 

[woodslinger]

I like the revised drawing, are the smaller rectangles plates on the outside or a joint of some type on the inside?

I'd go with Sean's idea of putting a plate over the joint to make sure everything stays tied together.
Although it seemed to me you had the issue licked with the concrete bases.

2 pros on the cradle idea:
1. like your other supports, the bolt allows the tree to grow without destroying your support or damaging the bark.
2. if the bolt fails, the cradle should still hold the tree till you can get back in to replace it.

 

[DMc]

DMc- not quite sure what you mean....

Just makeup the two 4x4s with a bolt out the top like the ones you pictured. Independently set them into the trunk at the A frame angle. They can be together at the top if the point of attachment is large enough or separated if that makes more sense. With one end in cement and the other in the tree, they will work as an A support because the tree joins them together.

 

[CurSedVoyce]

Just my thinking.
I would not sink the 4X4 wood posts into concrete. They will sooner than later rot out from moisture.
Use some sort of mounting hardware on top of the concrete to mount the post to. Also, there should be some sort of separation between the concrete and post often provided by the mount. Perfectly level poured posts also don't shed water well. A slight slope or rounded away from the anchor for drainage.
JMO.

 

[flushcut]

Clever thinking. I would've went with ½" bolts. No reason not to go with ¾". It doesn't make the install any more challenging.

What about this at the top- a horizontal piece and I ise a screw plate to connect the top three pieces together ...

(Pardon the crude drawing)

View attachment 66876


love
nick

Yep that's what I was thinking.

 

[flushcut]

I've always pondered a threaded rod with bracket assembly, be it vertical or horizontal. That way the supporting column assembly can be 'generic' or simple, and the attachment to the tree would be custom.

View attachment 66865

I can see this splitting the stem as, in my mind, it is pushing up against only half of the stem instead of the whole stem.

 

[MasterBlaster]

I don't think that would happen.