Wood Floor Truss with Damaged Plates

[BubbaJ]

Came across this repair while reviewing an existing structure with areas of excessive floor deflection. Several floor trusses have this repair, some have 2 screws per web.

I've only used plywood gussets to repair damaged metal plate connectors. It would seem that this screwed connection would allow slippage in the webs.

Has anyone else used this type of repair and if so, did you design it based on shear capacity of the screws?

Thanks in advance.

 

[dik]

It doesn't work... these trusses are in serious need of repair.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Agent666]

If you're putting ply gussets on each side to replace the failed nail plates, I'd look to make the reinforcement gussets full depth and turn that part of the truss (maybe a bay either side of the damaged conne tions) into a full depth plywood box beam. Ply for webs and top and bottom chords of truss as the top and bottom flanges of your box beam?

You can also nail off to the original diagonals and/or add other infill framing to suit ply panels.

I'd expect you'd get the numbers to work out quite easily.

 

[BubbaJ]

I had never, in my 20+ years, seen this done as a permanent fix. And I did not see how it was viable, but thought I would ask the question. Thank you both for your input.

 

[KootK]

I agree with you and the other gents, this is not a viable truss repair. For what it's worth, I used to design these things. Whomever did the repair didn't appreciate the massive capacity differential between a pair of toothed plates and a screw. The only place this might fly is at the zero shear location on the truss. And, even then, you'd be tempting fate in thinking that you knew the load distribution with enough certainty that you could locate that zero shear location with any accuracy. Just ask a piano about how uniform residential live loads really are.

 

[jayrod12]

Just ask a piano about how uniform residential live loads really are.

Or the 200 gallon fish tank....

 

[dik]

I've used plywood gussets and nails for repairing these, in past... and always use adhesive. You'll have difficulty obtaining strengths for adhesives. I should have noted earlier that a catastropic failure is imminent, even without the piano or fishtank.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik