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Truss fixity

Truss fixity

Truss fixity

We are currently load rating a truss where the connections are welded with gusset plates.  When we input the truss into STAAD we assumed fully fixed connections at the ends. The resultant moments in the members were relatively small, but since the members bend in the weak axis, the load rating is very low.  Is there any information out there that discusses partial fixity of such connections?

RE: Truss fixity

Where are the moments coming from?  Is the truss loaded between panel points?  

If there are large concentrated loads between panel points the truss rating could indeed be very low since the truss is not being used properly.  However, if you have a sufficiently stiff deck to transfer uniform loads to the panel points, it could be appropriate to assume pinned connections since "load goes to strength" and the panel points will be much stiffer than the individual members.

Please give us a little more information on the truss application (roof or floor, deck type etc..).

RE: Truss fixity

I just noticed that you "crossed posted" this in a few other forums.  Please try not to do this as it makes a continuous dialogue very difficult and discourages members from posting.

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