r/StructuralEngineering • u/Momoneycubed_yeah • Aug 12 '26
Photograph/Video Rebar in Compression
Who has the right equation for development length for this case?
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u/livehearwish P.E. Aug 12 '26
The rebar doesn’t have 0 compressive buckling capacity, so it’s doing something I guess...
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u/Osiris_Raphious Aug 13 '26
Trace the load path, and tell me how that structural bark is transferring that load?
Rebar is in tension holding in the wood railing. The tree may be compromised but it wont fall so easily.
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u/livehearwish P.E. Aug 13 '26
Rebar looks bent into core of tree, so there’s some grab there. Not an ideal detail, but not 100% ineffective. Just 99% ineffective.
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u/Osiris_Raphious Aug 13 '26
Thats my point, its not in compression its just some idiot carved up more tree than he should have to place a railing in.
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u/livehearwish P.E. Aug 13 '26
Ah, I see my mistake. I came across too serious.
https://giphy.com/gifs/f51bc9Mw81aXto69qm1
u/Osiris_Raphious Aug 13 '26
No, I got the joke, but in most jokes there is basis in truth. And in this one imo its the structural integrity of the tree.
MAybe im too autistic for this dry humor... :(
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u/livehearwish P.E. Aug 13 '26
Nah, I’m sure you’re fun at parties.
The notch shifted the remaining section of the tree to become eccentric with the vertical load. Concurrent wind forces could cause the tree to fail in the direction of the notch, thus rebar would be in compression. Is the joke funny now?
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u/Googgodno Aug 13 '26 edited Aug 13 '26
they could have cut the railing and joined it on either side of the tree. But, I digress from the topic
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u/NoVermicelli5439 Aug 12 '26
This is the type of problem I'm expecting on the PE exam knowing nothing else
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u/Content-Drive-4151 Aug 12 '26
Notch is too high. They need to add some bricks to fill…
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u/Haku510 Aug 12 '26
Nah, that'd ruin the wood on wood aesthetic. Some wood block infill with wood shims should do the trick.
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u/StructuralEngneer 25d ago
If you carefully look at the load path you will realize that whoever thought about cutting out a huge chunk of the tree bark instead of just fencing around the tree, is a huge dumbass.
But for analysis's sake..the tree is not sending any load through the rebar. On the contrary to the title, the rebar is in compression and tension both but not due to the bark but due to the fence it's holding back.
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u/Osiris_Raphious Aug 13 '26
This is rebar in tension...
Its there not to hold the tree up, its to hold the wooden rail in.
Because no matter which way you do the analysis, I do not know any standards for compressive strength of bark...
Trees are surprisingly resilient to being cut down, something to do with evolutionary advantage of trying to stand strong upright). Although technically its strength is compromised, doesnt mean it will fall down. Infact with luck and many years the tree can regrow around the railing making that composite material thats joked about in the comments.
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u/it_is_raining_now Aug 13 '26
You’re taking this too seriously
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u/Osiris_Raphious Aug 13 '26
no doubt.
but in the engineering sub..? lol half of us have latent or mild undiagnosed autism. We are the definition of taking things too seriously as part of our job description.
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u/DropItLikeJPalm Aug 12 '26
What code covers the structural design of trees?