Maximum absolute deflection in a ridge beam

[msdmoney]

I have a project with an existing ridge board and rafter ties, where the client wants to cut out the ceiling/rafter ties to vault the ceiling. The plan is to install a ridge beam that spans approximately 30 ft to support the existing roof. I'm just wondering if anybody typically limits the deflection above just the standard code maximums per length of the member to limit the thrust on the exterior walls. The roof pitch is 10/12.

 

[oldestguy]

OG once more. Since my experience of building may be something that others have done, I am wondering if the attachment of rafters to the ridge "beam", may be just as weak as mine, in ability to carry gravity loads from the rafters.A few toe nails may be all that makes the "bond". In that case, reinforcing the ridge beam won't take on any of some loads from the roof system. That means before proceeding, check what connection may have been constructed in the original job between rafter and ridge beam. Adding more to that joint won't be easy to have any benefit.

 

[bigmig]

What thrust at the exterior walls....model the tie-rafter with a roller and design the tie accordingly? Ridge beam construction with tension tie rafters? Seems like two systems doing the same job to me.

 

[msquared48]

All together it works, but alone it falls down.

Mike McCann, PE, SE (WA)