Pinned & Rolling support in Roof Truss (timber)
Pinned & Rolling support in Roof Truss (timber)
(OP)
Can anybody explain in simple terms for a truss newbie.
What is the difference between designing a truss with two pinned supports and designing it with one pinned and one rolling?
What is the difference between designing a truss with two pinned supports and designing it with one pinned and one rolling?






RE: Pinned & Rolling support in Roof Truss (timber)
With a rolling support, the lateral reactions are zero from bending.
RE: Pinned & Rolling support in Roof Truss (timber)
I'm not saying that it's wrong to design for a pin-pin support, just be aware of it and detail it out to match your assumed support conditions in the analysis.
RE: Pinned & Rolling support in Roof Truss (timber)
BA
RE: Pinned & Rolling support in Roof Truss (timber)
I always design with a pin rolling support. When would you ever design for a pin pin support?
RE: Pinned & Rolling support in Roof Truss (timber)
I think the NET of the axial forces will be zero, but I don't believe it will be zero along the entire length. If you imagine the first diagonal framing into the bottom chord, that will impart an axial load on the bottom chord. It will likely put the portion closest to the pin support in compression and the next segment would likely be in tension.
RE: Pinned & Rolling support in Roof Truss (timber)
Upon second thought, I believe you are correct.
Adam10,
I suppose the only time you would design with a pin-pin support is if you had a pin at each end. I don't recall ever seeing that situation in a real truss.
BA
RE: Pinned & Rolling support in Roof Truss (timber)
Garth Dreger PE
AZ Phoenix area
RE: Pinned & Rolling support in Roof Truss (timber)
By the way, have some of the posts in this thread been deleted or did I have one too many beers last night?
BA
RE: Pinned & Rolling support in Roof Truss (timber)
Michael.
Timing has a lot to do with the outcome of a rain dance.