trusses - realease conditions
trusses - realease conditions
(OP)
Hey all - I'm modeling a building for analysis in RISA 3D. The roof is composed of triangular, CFMF trusses. For a typical CFMF truss, what would the release conditions be? I know the individual web members should be input as pinned. What are the release conditions of the top and bottom chords?
Thanks in advance.
Thanks in advance.






RE: trusses - realease conditions
RE: trusses - realease conditions
RE: trusses - realease conditions
Mike McCann
McCann Engineering
RE: trusses - realease conditions
RE: trusses - realease conditions
1. I generally leave the top and bottom chords continuous and then design them to carry the combined axial load and moment. I do this because generally they are physically one continuous member and you can significantly reduce deflections of the system this way.
2. A true text-book truss does not resist any moments - so you would pin all of the members. In reality where the chords are actually one continuous member, at ultimate state since you did not design them for the moment they will form a plastic hinge and revert to the pin-pin system you designed for. No problem with this as it is not a collapse mechanism.
RE: trusses - realease conditions