Roof Beam replacement.

[BlueKnife]

I would not remove the bottom cord, or any other part of the truss, no matter what else is done in there.

Why?

 

[EddieWalker]

Every time you modify something, or remove part of a structure, you cause damage to what's remaining. It takes a lot more figuring out of things to know what you will end up with after the modification, then it does to do the modification. None of us know what is going on with that truss enough to suggest making any changes to it. Assuming that there is a ridge beam that can support rafters if the truss is modified isn't something I'm on board with, or willing to encourage.

Fix what's broken, make it stronger then before, and add more to it, but never do anything that makes it weaker.

 

[2manyrocks]

This thing has already broken once and several people have already had expressed different opinions on how to make the repair and whether the truss should have been designed and built this way. That's not a good situation to step into for someone trying to make a repair.

I'm just hoping it is now stable enough that a snow load this winter won't break it.

 

[BlueKnife]

Every time you modify something, or remove part of a structure, you cause damage to what's remaining. It takes a lot more figuring out of things to know what you will end up with after the modification, then it does to do the modification. None of us know what is going on with that truss enough to suggest making any changes to it. Assuming that there is a ridge beam that can support rafters if the truss is modified isn't something I'm on board with, or willing to encourage.

Fix what's broken, make it stronger then before, and add more to it, but never do anything that makes it weaker.

But we do know what's going on with it, or at least those of us who are intimately familiar with that style and dimensions of construction do. 30-40 ft. wide post frame buildings are ubiquitous in the OP's area. I live in one, in fact, as do many of my neighbors. I also build them, regularly, using the same methods I've been describing. The design and methods to build them are very well known and understanding the forces involved is not complicated once you've worked on, repaired and built enough of them.

 

[Streetcar]

Why?

The bottom chord is holding your walls in. Remove it and you just have your connections holding the walls in

 

[EddieWalker]

But we do know what's going on with it, or at least those of us who are intimately familiar with that style and dimensions of construction do. 30-40 ft. wide post frame buildings are ubiquitous in the OP's area. I live in one, in fact, as do many of my neighbors. I also build them, regularly, using the same methods I've been describing. The design and methods to build them are very well known and understanding the forces involved is not complicated once you've worked on, repaired and built enough of them.

I'm a contractor and I get a lot of work fixing what others have done wrong. Usually it's removing something that they where positive didn't need to be there. Only thing worse then somebody modifying something, is telling others to modify it without actually have hands and eyes on it.

 

[BlueKnife]

The bottom chord is holding your walls in. Remove it and you just have your connections holding the walls in

Not with a post holding up the center it isn't.

 

[Streetcar]

But we do know what's going on with it, or at least those of us who are intimately familiar with that style and dimensions of construction do. 30-40 ft. wide post frame buildings are ubiquitous in the OP's area. I live in one, in fact, as do many of my neighbors. I also build them, regularly, using the same methods I've been describing. The design and methods to build them are very well known and understanding the forces involved is not complicated once you've worked on, repaired and built enough of them.

If you take out the bottom chord, you are dramatically changing the stress on the members and their connections. the original failure was at connection and your recommendation is increasing stress in those connections

Not with a post holding up the center it isn't.

have you ever heard of the collapse of the balcony at the Kansas City Hyatt. Similar setup killed over 100 people when balcony collapsed

 

[BlueKnife]

I'm a contractor and I get a lot of work fixing what others have done wrong.

Same here. I deal with other people's poor workmanship quite regularly. In that, it sound like we're similar. One, (perhaps significant, perhaps not) difference though, is that I'm a contractor in the region where the OP is located, who specializes in the type, style of construction and general size of building that we're discussing.

have you ever heard of the collapse of the balcony at the Kansas City Hyatt. Similar setup killed over 100 people when balcony collapsed

I hadn't heard of that. I'll look it up. How many balconies of the exact same dimensions had the person who removed the supports built or modified before? Were there hundreds of balconies of the same size and construction style, dealing with the same loads in the area to compare it to?

 

[ning]

I wouldn't remove the bottom chord, because even with the left side of the (bottom) chord broken, there was still some tension functionality served with the rest of the truss - particularly once the bottom was braced:

Yes, putting in a ridge-to-floor support probably obviates the chord. Probably.
The only thing I'd consider is putting in a few extra studs in that wall right under the king post and remove the tree trunk replacement and regain that few inches.

Otherwise I wouldn't take it any further than he's already got it... but I do look forward to the next 10 pages of this thread now that the op's done

 

[BlueKnife]

I wouldn't remove the bottom chord, because even with the left side of the (bottom) chord broken, there was still some tension functionality served with the rest of the truss - particularly once the bottom was braced:
View attachment 833176
Yes, putting in a ridge-to-floor support probably obviates the chord. Probably.
The only thing I'd consider is putting in a few extra studs in that wall right under the king post and remove the tree trunk replacement and regain that few inches.

Otherwise I wouldn't take it any further than he's already got it... but I do look forward to the next 10 pages of this thread now that the op's done

In case it wasn't clear, I wasn't suggesting that the bottom cord could be removed with things as they are now. I was suggesting it could be done if there was a single, floor to ridge post, as you mention. But, as I said before, I think he's fine with things as they are now (at that truss).

 

[Chewwy]

. . .

have you ever heard of the collapse of the balcony at the Kansas City Hyatt. Similar setup killed over 100 people when balcony collapsed

I have heard of it and studied it. There is little similarity other than a faulty design although it is not clear that the truss actually even had an engineered design.

BTW, the Hyatt event involved elevated walkways, not balconies.

 

[Streetcar]

I have heard of it and studied it. There is little similarity other than a faulty design although it is not clear that the truss actually even had an engineered design.

BTW, the Hyatt event involved elevated walkways, not balconies.

Fabricator Modified design which greatly increases stress In member. Member failed due to increase stress

 

[Chewwy]

Fabricator Modified design which greatly increases stress In member. Member failed due to increase stress

For the truss in this thread there is little evidence of the fabricator modifying its design or that an original design ever existed. It may have been just constructed.

 

[BlueKnife]

Fabricator Modified design which greatly increases stress In member. Member failed due to increase stress

The truss in question here didn't have a "designer" per se, other than whoever built that building. That's clearly not a commercially made, engineered truss. The member failed because of the "design", not because the design was modified.

 

[Streetcar]

some people are recommending changing the truss by removing lower chord. Making center column in two pieces drastically increases stress in the joints

 

[BlueKnife]

some people are recommending changing the truss by removing lower chord. Making center column in two pieces drastically increases stress in the joints

I didn't see anyone suggest a two piece center column.

 

[Streetcar]

I didn't see anyone suggest a two piece center column.

That was the actual repair done

 

[chim]

Lots of people think they know how things work - but really don't. A number of years ago I read a lengthy piece in a farming publication my FIL subscribed to. There was a big story on building collapses during a larger snowstorm. Most were caused by owners doing mods to their buildings after the buildings were completed by the contractors.

One of the main problems was making attachments to the bottom chords of trusses for walls or stall dividers. Some were homebrew "supports" that owners added. When solid attachments were made, it changed the dynamics of the stresses and didn't allow for the truss to flex as it should. The "support" created a failure point.

They had pictures of good and bad connections. The bad ones created a solid connection between the floor and the truss. The good connections were made solid to the floor and went past the bottom of the truss, going through a guide so the truss could slide up or down.

IIRC, the Hyatt tragedy was caused by the failure of the anchors. Someone decided the ceiling rod supports were unsightly and eliminated some?

 

[BlueKnife]

That was the actual repair done

Yes. And no one suggested removing the lower cord with the repair as it is now.