Just thought this my produce pictures of some seldom seen(at least hopefully seldom)mistakes in beam sizing.
(https://forestryforum.com/gallery/albums/userpics/10017/brkbeam.jpg)
This is a hayloft beam in a roughly 30' wide barn. I'm guessing the beam is about 6x8 around 15' span :o. Should be about half that. They put 2-2x's under and a scab across the break. This whole barn was built poorly and too light. I can think of several other similar broken barn beams around here. Hay is heavier than people give it credit for. Its usually a combination of overload and/or some insect or water damage.
I'm not sure if I locked up the machine before the PM sent, just holler, we'll be home :).
We broke a beam like that one year when we filled the hay loft real good. After we were done and the boss was standing talking to us there was a big crack,pop sound and then we all ran into the barn to see the beam broke.
I guess that the older barns could hold alot of hay the old way but not alot that is baled.
Thanks Alot Mr Mom
Here is one:
(https://forestryforum.com/gallery/albums/userpics/10095/l%20Center%20span%20with%20broken%20girt.JPG)
This shot shows a tie beam (I guess you'd call it that) that goes over the drive aisle of a large barn. The tie was joined over a brace with only a half lap joint and either it isn't placed right or sized right and it has failed.
Here is another:
(https://forestryforum.com/gallery/albums/userpics/10095/f%20Half%20lap%20over%20post.JPG)
Although this beam hasn't failed yet; you can see that it's on it's way. The joint has opened as the half lap scarf wasn't placed in the correct location and it wasn't secured properly.
Jim Rogers
I have seen many half laps in mid span where they needed a continuous joint. Sometimes the farmer not knowing the problem would have a small steel plate bolted on, trying to hold the ends together.
Here is one...
(https://forestryforum.com/gallery/albums/userpics/13089/tiebroke.jpg)
Any thoughts?
lazy-river
Looks like the roof leaked, rotted out the beam, and someone scabbed on a piece to hold it together. Then they put on a new tin roof. Prolly not holdin much tho.
Looks like it the beam was in tension and a bending load on the beam outside of the picture frame. Or it was under tension and got smacked by a tractor loader. The scab looks like it has been there a while so maybe it was a smack on the side from a piece of equipment.
Quote from: lazy-river on March 21, 2007, 07:04:21 PM
Here is one...
(https://forestryforum.com/gallery/albums/userpics/13089/tiebroke.jpg)
Any thoughts?
Having a better photo would help. I see now what slowzuki is seeing, and that is about a two-inch separation (pulled apart in tension) of the wood. (looked like rot to me initially)
If that is the case, then I would suspect failure occured before the beam was put in place. Maybe when the tree was felled (across a log, for example, and there was a compression break in the wood which went undetected until there was a snow load. Then the failure pulled apart due to a tension load (and maybe the scab was added later or even when first assembled).
Good, sound wood won't pull apart in tension that way unless there is a failure from an outside source (improper handling, equipment like the loader slowzuki mentioned) IMO.
Still, posting the pic at 30k would help a lot for clarity needed to see the failure. Good example of how important proper felling, and handling, as well as grading and handling are before construction when using wood beams.
This should be better quality. if anyone would like to try and post some at a better quality, I can send you some originals. I am pretty sure this barn was mostly yellow pine, lots of powder post beetle sign. I also thought it might have been hit hard with a piece of equipment. I dont recall seeing any obvious sign roof leakage, at least not in this section.
let me know if anyone would like better pics. i had never seen this before.
(https://forestryforum.com/gallery/albums/userpics/13089/tiebroke%7E0.jpg)
The brace is out of pocket also. I assumed you were gonna tell us about junior and the tractor :D. Old house borers and ppb's will really weaken a beam, they usually accompany failures I've seen. Up until the early 70's we were using tension numbers that were... optimistic ::). Early glulam and heavy timber truss work is often in distress from that.
We pulled a 2x10 syp apart in grading class, it took a little upwards of 18,000 lbs and ripped apart along about a 4' section. The break here looks brash and short. Course every break is unique.
Look closer at the pic.
The post and right hand section of the beam are lower then the left hand section of the beam.
Here's one that would have failed shortly; a 6x8 reduced to 10% (?) of its section through rot. At the time of purchase, it supported a leaky hip roof in our building complex . The whole corner was evidently in poor shape, but I didn't realise how critical until after I'd been up on top performing the demolition. :o
(https://forestryforum.com/gallery/albums/userpics/15066/canti_3.jpg)
Furby,
If I remember from this barn, the post you mention that is lower has something to do with the sill plate it was sitting on.
The post was the right hand post of the large opening and the whole opening was sagging just a bit.
I bid on the repair for this barn, but the owner sold the farm on a whim. It would have been interesting to spend more time with this barn to learn more
thanks
Andy
Not a problem with sizing, but here's more rot and bugs
(https://forestryforum.com/gallery/albums/userpics/10017/cabinback.jpg)
Termites often don't (I've heard can't) chew the medullary rays. This sill is facing the way it was in the cabin. Imagine rainwater entering a check, moistening and softening the wood under the check.
(https://forestryforum.com/gallery/albums/userpics/10017/termitelog.jpg)
I think it's time to SEPARATE design failures from NEGLETIC failure. The later (neglect)will endure if you have AT LEAST/maintain a foundation/roof for many years/centuries (e.g. older than ANYONE on this forum...), the former (design) will be waiting for the first big wind/snow to fall over......
I think most here tend to emulate the later.......I hope!
P.S. Great thread, keep them coming.....
OK Tony_T, I think I appreciate that distinction; I was just warming up ...
This is the overview. Its actually a sawmill building, next to a river from which it took its power via a 10ft undershot waterwheel. The intention was for sheltered loading with the 5 great cantilever trusses. Each truss is about 30ft long, and the cantilever is about 9ft. Section of cantilever beam is approx 10x8. Roof covering is clay tiles.
(https://forestryforum.com/gallery/albums/userpics/15066/canti_4.jpg)
They got it wrong. All 5 have cracks most evident in the upper (tension) half of the beam.
(https://forestryforum.com/gallery/albums/userpics/15066/canti_1.jpg)
Damage has been arrested by building concrete pillars under the end of two cantilevers. However, further results are opening of the upper king post joint (appears never to have been pegged)
(https://forestryforum.com/gallery/albums/userpics/15066/canti_2.jpg)
AND tipping of the canti posts on their pedestals
(https://forestryforum.com/gallery/albums/userpics/15066/canti_5.jpg)
In one instance, the post remains squared up to the pedestal, but the latter has bee forced to rotate! (no pic).
What might be done to set this in order ??? ;D
The cantilever is bearing mid-span but obviously is not designed for it. The top wasn't pinned because it looks like they took a truss design that should have always been in compression in the top chord if end supported.
Very scary to see people build stuff like that. Can you imagine in a conventional truss building if you set the 2x3 bottom chord so your supporting wall was mid-span? SNAP! Not much room for flexure in a stick framing truss.
I don't know what can be done to set that right Griffon, that is spooky. You sure can't put those in tension now. My fear is if while disturbing that, if one of those broken bottom chords separates, everything might let go. It needs an engineer but I imagine a steel rod across the bottom and outer posts. Getting from here to there would have to be done with a whole lot of thought.
This is another kinda off topic, but hopefully a good heads up.
It didn't fail, we pulled it. This was a timberlinx end connected non structural ridge.
I split it where it had developed a massive check. Looking at the heart and where the connector was placed it was dead on the radial line from the pith. There probably couldn't be a worse location if you tried. Imagine the connector being several inches lower crossing the rays instead of in plane with them.
(https://forestryforum.com/gallery/albums/userpics/10017/tlinxcheck.jpg)
Hey,
What's up fellas? I knew you guys would make a great thread out of this. Thanks alot you guys. I wish I had some pics to post but that is why I asked you guys because I have none. Well I guess I do now.
Trying to tell what the timberlinx orientation was but it looks like you where trying to keep the ends of two posts aligned with each other and tight together? If so a timberlinx would be a bad choice if there is any tension (I guess thats obvious now).
Quote from: Don P on April 08, 2007, 08:30:01 PM
This is another kinda off topic, but hopefully a good heads up.
It didn't fail, we pulled it. This was a timberlinx end connected non structural ridge.
I split it where it had developed a massive check. Looking at the heart and where the connector was placed it was dead on the radial line from the pith. There probably couldn't be a worse location if you tried. Imagine the connector being several inches lower crossing the rays instead of in plane with them.