Bottom Chord of Roof Truss Cut
Bottom Chord of Roof Truss Cut
(OP)
Hi all,
I am trying to retrofit and reinforce an existing roof truss that had a portion of its bottom chord cut for attic stairs. I am analyzing this truss in RISA and am having some issues with getting a repair to work. I have modeled trusses in RISA and by hand before, so I am confident that my model is done correctly. What I do need help with is some possible repair options. I have tried adding in some additional web members and reinforcing what is currently there and I expected there to be issues because we are basically changing the load path of the truss, but I was note expecting the members and joints to be this overstressed. See the sketch below and you will see the truss that I am dealing with. It is a wood roof truss made of 2x4 members @ 2'-0" o/c with a plywood roof deck, gyp board/drywall along the entire bottom chord, and some plywood in the top of the bottom chord for some storage. Any help is much appreciated. Thank you in advance!
I am trying to retrofit and reinforce an existing roof truss that had a portion of its bottom chord cut for attic stairs. I am analyzing this truss in RISA and am having some issues with getting a repair to work. I have modeled trusses in RISA and by hand before, so I am confident that my model is done correctly. What I do need help with is some possible repair options. I have tried adding in some additional web members and reinforcing what is currently there and I expected there to be issues because we are basically changing the load path of the truss, but I was note expecting the members and joints to be this overstressed. See the sketch below and you will see the truss that I am dealing with. It is a wood roof truss made of 2x4 members @ 2'-0" o/c with a plywood roof deck, gyp board/drywall along the entire bottom chord, and some plywood in the top of the bottom chord for some storage. Any help is much appreciated. Thank you in advance!

RE: Bottom Chord of Roof Truss Cut
MiTek Roof Truss Repair Details
RE: Bottom Chord of Roof Truss Cut
RE: Bottom Chord of Roof Truss Cut
RE: Bottom Chord of Roof Truss Cut
RE: Bottom Chord of Roof Truss Cut
This way you can reinstate the bottom chord.
Aside that thhe truss will need to be re analyzed with a raised bottom chord in that area and plywood gusset plates for connectors
RE: Bottom Chord of Roof Truss Cut
RE: Bottom Chord of Roof Truss Cut
If they want this cheap, then relocating the stair and reconstituting the bottom chord is the cheapest proposal.
RE: Bottom Chord of Roof Truss Cut
Anyway, thanks everyone for the help and recommendations, I do appreciate it!
Matt
RE: Bottom Chord of Roof Truss Cut
RE: Bottom Chord of Roof Truss Cut