Design of a tree as a structure / inspectors gone wild 15

[jwilson33]

A client of mine installed small light fixtures (12" arm, small single bulb light with about .5ft^2 of projected area. The trees are 40ft+ tall oak trees with 12"-18" trunks. The inspector is claiming that the trees become structures as defined by the IBC Code 2009 because of the addition of a fixture. He now wants full calculations to demonstrate the tree will not blow over in a 90mph wind event.
We have gone back and forth, but he has dug his heels in and told the client they have to file for an appeal through the zoning board of appeals. I have demonstrated by calculation that the load added to the tree is less than 2% of the current load on the trunk alone and therefore the added load does not warrant a structural upgrade. But he rejected that argument because this is a change of use and the tree must now fully meet the current Code.
I am looking for something in the Code that might demonstrate that the tree does not become a structure by addition of a light fixture, or some other slam dunk wording. I am sure he knows his argument is foolish, and the reasons for this probably have nothing to do with the lights on the trees.
A picture of the installed fixture is attached.

 

[3DDave]

http://www.youtube.com/watch?feature=player_detailpage&v=GxLEopDKk-E#t=26

 

[nac521]

Not sure if this will help, but check out

http://treehouses.com/joomla/index.php/building-specifications-and-stress-analysis-report

This article describes story of the Out 'n' About, a treesort located in Takilma, Oregon and the process to verify the structural use of live tress.

 

[JStephen]

Supposing you have an area with NO building codes at all, and they establish a building code. Are existing structures grandfathered in? And are these trees older than the local building code?

 

[coolad2007]

More than anything i am worried about the precedent this case is going to put on rest of community if you allow such light fixtures be installed on trees in such heavily wooded area. What is there to stop others from adding more of it on rest of the trees as time progresses. How would you eventually control and say enough is enough. If it was one off case i would shoot the inspector and rest the case, however as you said this a heavily wooded area and people prefer this method. There has to be a limit on such applications or periodic check stipulated on this area as CANPRO stated to make sure you do not endanger public safety at large. I think inspector's main concern here is what is the proof that the system would work. Like building which require 40 year re-certification to justify that they are still structurally safe and can be operational, what is there for trees on same lines?

You all may kill me for this but i am all in to support the inspector's comment. I think he is not asking for calculations to prove that tree can take such load but he is asking what if the tree falls and you entire grid fails. NOTE: I have seen a lot stupid contractors and clients who do things which eventually help lawyer's make a killing out of it.

--ad

 

[TehMightyEngineer]

I don't think adding lights qualifies as major modification of an existing structure per the International Existing Building Code. Therefore it should be acceptable as is without design.

Seriously; cite the inspector the IEBC and let him chew on it.

Maine EIT, Civil/Structural.

 

[TehMightyEngineer]

Never mind, just saw above that you tried that.

Maine EIT, Civil/Structural.

 

[kingnero]

send him some ridicoulous calcs, with some made-up factoring of all kinds, showing the structure is fine with the additional lights. As no-one did this before, he can't dismiss them on the basis of being wrong. And if he asks where your calcs came from, say you'll redo them when he shows you the appropriate code.

 

[ztengguy]

Coolad, what if the transformer is struck by lightning and the lights go off? Not the end of the world. Not a reasonable argument.

 

[jwilson33]

Coolad- The precedent was set long ago that it is okay to mount small fixtures in trees. Preventing fixtures in trees by asking for structural calculations on a whole tree is akin to preventing roadside sign structures by forcing people to design them to resist impact forces from a tractor trailer. If a local governing body wants to control or prevent this condition, then they need to write it into their local zoning ordinances so everyone is on the same page.

 

[manstrom]

It sounds like the inspector's request is to justify the wind resistance of the "structure" as opposed to its ability to hold up a light.

I don't know how one would create calcs for a tree. I have some ideas, but I don't think calcs are the answer. Precedent may be the best bet. I wonder if there are any lights mounted in trees in parks or other government property. The inspector would have a hard time arguing with that.

 

[LittleInch]

Play him at his own game. The key is in this sentence for me "By mounting the lights to the tree you are making them a structure; therefore they are not existing structures" - utter rubbish.

If, for the sake or argument, by adding something (the light fixture) to something else already existing (the tree) you now look at that thing as a "structure" it simply must have been a "structure" before you added it. You cannot "make" an existing thing a structure just by saying it is one and then ignoring the fact that it is already there. Therefore the existing structure rules come into play about not needing any change if within a certain percent. This is pure logic.

I can see to a certain extent that if you add something really big to a tree it could affect its strength / ability to stand up, but clearly within the size of the light fitting he is being extraordinarily belligerent.

Good luck and please come back and tell us what the result is in due course.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[btrueblood]

Along with LI's last post, I had this train of thought:

Modifying the tree has caused the tree to become a structure (a device providing a support function for human use) (inspector's argument).

Therefore, any modification of trees must come before the city planning department for approval/review. Existing trees must be structures, since they often provide support for shading purposes, or to hold ornaments (leaves) for human enjoyment, or as recreational structures for kids (tree climbing rug monkeys).

Therefore, all changes to all trees must be reviewed by the city planning department.

This would include, presumably, modifications that reduce the tree's structure, whether pruning/trimming, or naturally caused detachment of parts of the tree as well, i.e. wind damage, just as you would inspect a house that lost some siding in a windstorm. Limbs - hmm, well sure that sounds reasonable. But what about annual massive loss/replacement of sail area in the form of leaves?

Start sending him pictures of every tree on the property for review and approval. Ask if the existing structure (tree) should be demolished, as they do not meet code.

Better if you can send pictures and questions regarding the trees in the inspector's own yard.

 

[bridgebuster]

Excellent point. A thing can't be and not be at the same time. Where's St. Thomas Aquinas when we need him? Or for that matter Mike McCann?

What happens if a bear climbs into the tree; are we exceeding the live load capacity of the tree? What if there's snow on the tree along with the bear?

 

[fegenbush]

Start sending him pictures of every tree on the property for review and approval. Ask if the existing structure (tree) should be demolished, as they do not meet code.

Better if you can send pictures and questions regarding the trees in the inspector's own yard.

Pay attention, people. This is how it's done.

 

[dcarr82775]

Maybe this is a suitable response to the Inspector:

Mr. Inspector, what you've just said is one of the most insanely idiotic things I have ever heard. At no point in your rambling, incoherent letter were you even close to anything that could be considered a rational thought. Everyone who has heard of this issue is now dumber have having heard of it. May God have mercy on your soul.

Almost certainly the 1st and only time the movie Billy Madison will be referenced on this website.

 

[MJB315]

What is the occupancy category of a tree?

"We shape our buildings, thereafter they shape us." -WSC

 

[1gibson]

According to the inspector's letter, the act of mounting the lights to the tree makes it a structure. Well they are already mounted, so the trees have already been transformed into structures.

So remove the lights and apologize for unknowingly transforming the trees into structures, have inspector agree in writing that this is the case, and by removing the lights it is resolved.

Then mount the lights again, to the now "existing structures" as acknowledged by the inspector, with your minimal load increase calculations.

 

[woodman88]

Ask the inspector which section of the IBC applies to landscape/walkway lighting? In Arizona an building inspector is required to state the code section.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[woodman88]

Also,since people/kids can crimb the tree ask what the building code required live loading on the tree limbs are for your calculations.
Any answer (or non-answer) should give your something to take to the Building Official or City.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[dicksewerrat]

Is it possible to get the total response from the officials at the hearing? Call TMZ

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com