Continuous Cross-Ties in Gabled Roof

[DCBII]

I have a gabled roof diaphragm with a 30 deg slope and a ridge beam down the center. I've calculated my wall anchorage force, and I'm designing the roof joists as continuous cross-ties for the diaphragm. I'm looking at a free body diagram of the roof joist/cross-tie under the wall anchorage load. Since the wall anchorage force is applied to the joists at the eaves (which are lower than the ridge beam), it seems like there's an unresolved moment due to the slope of the joist. How are other people handling this? Does the wall provide a reaction against uplift that balances this moment, or are you designing the weld of the joist to the ridge beam for the cross-tie force as well as an additional moment?

 

[KootK]

Does the wall provide a reaction against uplift

Yeah. I think that you start by deciding how much, if any, of the anchorage force is being passed through to the diaphragm opposite the ridge. Then you're off to the races with equilibrium.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.