Cathedral roof 1

[Junior1234]

Hi eng tips family

Im dealing with a 45 degree pitched roof. How do i design the wall to resist the thrust. The wall is a standard stud wall 90x45 @450cc

Please let me know if there are any australian standard code sections i can refer to

Thank you all

 

[dhengr]

Junior1234:
You install ceiling joists/ceiling ties, btwn. the joist bearing ends, of joist pairs, and at the top of the wall top plates. I’m sure there must be some code section which suggests/implies that the walls must remain standing and support all the imparted loads upon them. Come on…, pretend to be an engineer.

 

[Junior1234]

Hi Dhengar, thanks for giving me a typical builder response, would you pretend to be an engineer and tell me how what calculation checks must be done
thanks mate

 

[MIStructE_IRE]

Yes Junior, that’s exactly how you approach someone for help…

 

[Settingsun]

Rubbish responses can expect a bite in return.

You could tie the rafters, otherwise use bracing/shear walls but have to get the load to them.

Does the situation allow you to get creative?

 

[HouseBoy]

Some detailed info might help.
How long and how tall are the walls?
How wide is the roof?
I'm not sure what you know or don't know.
Can you design the top of the wall like (or reinforce it with) a horizontal beam?

steveh49 - That roof looks cool. I'd sure like to know how the anchor those curved rods....

 

[XR250]

I'm with Dhengr. Grab you calculator. Determine the thrust load. Apply that to the wall top plate and figure out how to make it span horizontally. It ain't going to go too far without some steel integrated into it or some cross ties that have been previously suggested. The building code is not intended to help us through these types of problems - the laws of physics are.

 

[Settingsun]

Houseboy, it doesn't exist. It's from a hypothetical conversation between engineer and architect about how designs can evolve. The building started rectangular, with those chamfers (in plan) introduced to anchor the chains. No detail discussed, just enough to note it's something that needs to be addressed.

 

[HouseBoy]

Steveh49
Sweet.
Not very redundant though....

Thanks

 

[dauwerda]

Or install a ridge beam and eliminate the thrust.

 

[JLNJ]

How do you know you have thrust? Maybe you don't.

 

[jayrod12]

How do you know you have thrust? Maybe you don't.

I agree with this statement. I did a cathedral style roof but it was with metal plate connected wood trusses and they were able to resolve the "thrust" in the truss design. Which means a small amount of lateral movement of the wall tops allowed the trusses to act as a pinned roller type analysis.

So it is very dependent on the situation.