Bending Moment on Rafter Tie 1

[kwoolf1]

thread507-457041

Hello,

The above thread is very helpful but it is closed now. Looking at ARPASEVAN's formula and diagram it seems like the moment is calculated for the rafter, but not the rafter tie? Would the same bending moment be applied to the horizontal rafter tie (i.e. raise ceiling joist)? If so, the rafter tie has to also be sized to resist the bending moment? My garage is the same configuration and the rafters are 2x8 and the ceiling joists are 2x6.

If the allowable moment checks out for a 2x8 rafter, will a 2x6 rafter tie still work? Thanks for help and I'd be happy to provide additional information.

 

[JLNJ]

Do you have a moment connection between the tie and the rafter? If so, how is it accomplished/constructed, and why have it at all?

If you have no moment connection between the rafter and tie, how does flexure make its way into the tie?

 

[KootK]

Would the same bending moment be applied to the horizontal rafter tie (i.e. raise ceiling joist)?

Normally, end moments would not be applied to the tie and the engineer would assume that the connection between the tie and the rafters is a pin. And that's a good thing because the tie usually does not possess the bracing required to resist end moments that would put the top of the tie in flexural compression.