beam size and load engineering help

[Kyle Murphy]

Can anyone help me with the formulas that I need to calculate beam sizes for loading?
Also with roof loading calculations
I have a possible purlin style barn roof that would need to carry slate
The weight of the slate is 1000 lbs per square(100sq. ft.) with a pitch between 8/12 and 12/12...
Any resources or help would be greatly appreciated!
Thanks
Kyle

[dukndog]

Kyle,
I designed a barn here https://forestryforum.com/board/index.php/topic,50714.0.html and Jim Rogers has been helping me with figuring the loads and beam sizing. With the little bit of info you gave it's hard to come up with a beam size. Please look through the mentioned link and see how Jim comes up with roof loading and what figures are needed to come to your answer.
DnD

[Jim_Rogers]

As dnd has mentioned the load of 100 lbs per sqft is just part of the information needed. This slate will be attached to something. We need to know what that is and what that weighs per sqft as well. With these two weights we'll have a start on the dead load amount.

Next we'll need to know what the "live load" for the roof is. That is a snow load. I know it's probably not much in that area. But it has to be figured in.

What type of wood will the purlins be?
What type of wood will the rafter be?

What is the spacing between the rafters?

You need to gather this information up and post it and we can see what might work.

Jim Rogers

[Jim_Rogers]

Also, we'll need the plate spacing. That is how wide is the building?

[Kyle Murphy]

Here is the basic bent design.
There are no braces yet and I may add queen posts to support the roof load between the rafter and tie beam.
The building should be close to 50'x50'
All wood will be white pine.
The snow load is between 15-20 lbs per sqft
Not sure what the roof decking will be but the Slate I found out should be calculated at 15 lbs per sqft of roof area. but for calculations sake lets go with 1" pine decking for the roof sheathing
The rafters and bents are spaced at 12' 6" on center with 5 bents to get the 50'
the rafters are 8x10s at this point with 8x8 post then the shed rafters are also 8x10s with 6x6 posts
8x12 king post.
I don't think I can get a 24' long Tie beam that would be great! then I could get rid of the tension on the kingpost foot.

[Jim_Rogers]

Can you post that plan in the Plan section?

[Kyle Murphy]

Put what I have drawn so far in the plan depository.

[Jim_Rogers]

Thanks I have downloaded it and will review it now.
I'll post my comments about it there, not here, so we don't have two threads going about the same thing.