Load Calculation Help

Daniel24 · 10 Oct 2008 at 10:47 AM

Hello,

I am wondering if there is a kind soul here who could write a simple description of how to calculate loads and design in wood.

Let's take an example where I have a house that is 8m in width and has a standard gable roof. I want to get the correct dimension for the beam that I need to place from wall to wall. This beam has a common insulated wood facade on the top side and a glazed underside with a door and window. The top edge of the glass part is 2.4m, and the distance from the top edge of the glass part to the ridge is 2.9m. Assume that the gable roof starts approximately at the same height as the top edge of the glass part.
It would be really great if someone could show which formulas are used and explanations for them. A quick answer would be really nice.

Thanks in advance
Daniel

anaitis · 10 Oct 2008 at 11:31 AM

Start by posting a drawing!
Difficult to comment otherwise.

Daniel24 · 10 Oct 2008 at 11:38 AM

here is a pdf... kind regards /Daniel

anaitis · 10 Oct 2008 at 1:09 PM

The gray on the drawing, what is it?

Daniel24 · 10 Oct 2008 at 1:18 PM

Don't worry about the gray on the drawing, it just symbolizes that the outer walls and the roof project from the gable facade.

anaitis · 10 Oct 2008 at 1:19 PM

Is there a truss in the gable?
What is the c/c spacing of the trusses?

Daniel24 · 10 Oct 2008 at 1:32 PM

Yes, it is a truss with cc1200. The truss has already been dimensioned by another person; what I am looking for is how to calculate the horizontal beam that will sit on top of the glass panel.

anaitis · 10 Oct 2008 at 1:39 PM

Daniel24 said:
Yes, it is a truss with cc1200. The truss has already been designed by another person, what I'm looking for is how to calculate the horizontal beam that will sit on top of the glass panel.

If you have a truss in the gable as well, then a beam over the window section will not take any useful load unless the attic is furnished. Even if there is a load on the attic floor, it is probably suspended from the truss.

In other words, the beam over the window section will be there to attach the windows, to act as a reinforcement between the truss and the windows. You then choose a size for the beam that fits dimensionally against these two parts. It should also stiffen up, guide, the top edge of the panel so it cannot be made too weak. One might think that a 45 mm wide of suitable height would be appropriate.

Daniel24 · 10 Oct 2008 at 1:43 PM

Type 45x120 mm?

Do you have any formulas for how to calculate otherwise, with explanations of the symbols? Would be fun to learn.

Regards /Daniel

Daniel24 · 10 Oct 2008 at 1:57 PM

the roof truss is located 380mm behind the gable wall.

anaitis · 10 Oct 2008 at 2:28 PM

Daniel24 said:
the roof truss is 380mm behind the gable wall.

Then maybe you'll need some brackets to attach with.

anaitis · 10 Oct 2008 at 2:30 PM

Daniel24 said:
Type 45x120 mm?

Yes

Daniel24 said:
Do you have any formulas for calculating otherwise, with explanations of the symbols? Would be fun to learn.

Best regards /Daniel

Requires a bit more than a list of formulas.
Sorry