Has anyone ever used light gage steel framing to repair a damaged truss? Apartment buildng had a fire, burned through bottom chord between panel points. Contractor suggested applying 18 ga metal stud to each side after piecing in 2x4. Would this work?
I have seen this type of damage repaired using a 2x4 each side of the chord, lapping each end and nailing through. No reason why a pair of metal studs wouldn't work if they are adequate to resist the required force and can be connected adequately to the chord.
If the trusses were prefabricated by a truss fabricator, you should probably get his thoughts on what to do.
So this through crack (at the knot in a 2x4 truss in my overhead) could also be spliced (should be spliced!) with a pair of 18 inch long 3x1/8 plates on each side?
If the only damaged element is a tension member, I see no reason why you would not use material to be in-kind. As long as there is enough room for proper nail fastening and the nearby joints arent damaged, I'd tell him to splice it with 2x4 each side with structural adhesive and proper nailing. If its one or two-family dwelling, the IRC has a table for fastening splices and sistering of members.
Now, if it were a compression member, Id replace the members and create a "shell" around the damaged area with structural plywood (both sides), nailed and glued to stabilize for buckling.