Timber roof trusses
Timber roof trusses
(OP)
I'm doing some work on an existing building with timber roof trusses. I have never seen a truss with this configuration or these types of connections before. (See attached photos.) Has anyone seen these before?






RE: Timber roof trusses
RE: Timber roof trusses
RE: Timber roof trusses
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Timber roof trusses
RE: Timber roof trusses
I'd run away like crazy, the amount of conservative assumptions you would have to make to put a number on those to cover your rear is probably going to make these trusses unusable to the client. Then, to spend the time to find the exact capacity would likely take too much time on your end.
The only way I'd personally tackle this is if I could reinforce each of those interior "hip" joints with custom metal plates and through bolts (stupid expensive I'm sure).
Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries
www.americanconcrete.com
RE: Timber roof trusses
Please remember: we're not all guys!
RE: Timber roof trusses
RE: Timber roof trusses
RE: Timber roof trusses
Since I'm not aware of the methodology of determining a plate capacity for that type of connection - and since the condition is so poor - I'd either not take the challenge or propose that the only solution to me signing off on them would be to physically add my own gusset plate connections (plywood/glue/screws perhaps?) to fix the truss capacity.
All of that sounds like a lot of work (and money) for a solar panel.
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RE: Timber roof trusses
Mike Halloran
Pembroke Pines, FL, USA
RE: Timber roof trusses
Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries
www.americanconcrete.com
RE: Timber roof trusses
Inspect the existing trusses carefully. If they are satisfactory, the small additional load of solar panels is not likely to be a problem. If the existing trusses are not deemed sound, fix or replace as necessary.
BA
RE: Timber roof trusses
Truss plate not engaged in the 1 o'clock position web on first 2 trusses
Are truss plate installed in pairs in the 180-degree position on opposite faces of sheathed truss chord members?
Photo 3
Plate not centered on webs
Evaluation issues:
Truss plate gauge, and strength
no bracing visible
wood grade and species
attached is a document about truss evalauation
RE: Timber roof trusses
RE: Timber roof trusses
I have seen that type of connections before. But I think that the plates are usually pressed into the wood from both sides of the connection. That means two steel plates for each connection. I can't see in the pictures if that is the case for the example. And the examples I have seen were factory built.
As for the layout of the truss, that was odd. Perhaps somebody wanted to have a walkway at the center.
Thomas
RE: Timber roof trusses