I'm having some problem figuring out the size of my ridge beam (or maybe a parallel cord truss if the beam ends up being to big)

I attached pictures to my Google picture website which you can visit below

http://picasaweb.google.com/tristan.burm/Tellico

The span of the area that does not have an upstairs is (2x) 26 feet (clouded as number 1) the span in the opposite direction is divided into 3 beams (2x) 18.5 feet and (1x) 26 ft (clouded as number 2). The two beams in the open space will be connected to the other 26 feet beam (hopefully my bad explanation and the picture can help you out)

I’m wondering if anyone can help me design the beam size for this type of ridge

Thanks in advance for all the help

Tristan:

This is not a trivial design. You need the help of a professional engineer who can factor in your local design loads, etc. You'll need to provide a lot more information, starting with the timber species.

As I'm sure you're aware, some central posts would probably solve all your problems. Good luck with yoru project. CB.

CB,

Thanks for the response. I understand that a center beam would get rid of my trouble, but it takes away from the openness of the space, if you know what i mean. The material is ponderosa pine bending = 1100 psi and i can cut up to 36" in b and d.

Could you maybe supply me with the steps to see how big this beam is going to be.

thanks

daiku offers good advice.

I suspect it will be near impossible to design those ridge beams as shown as structural load carrying members. If you can not accommodate a ‘center’ post you may want to consider posts on the outside of the ‘open center box’ or incorporate some sort of queen post and upper purlin plate support to ‘break’ the rafter run.

Thanks,
pete

MTF not sure I understand what your saying. Trying to visualize it but don’t see it.

Any possible solutions car more then welcome; I'm having a design block I guess for a lack of better terms

What if I did a parallel cord truss like in the picture I just uploaded?

http://picasaweb.google.com/tristan.burm/Tellico/photo#5052681134069626962

Thanks everyone for their advice

Tristan.

If you can't calculate the load, then you can't know if it's strong enough. You need the span, the snow load, the dead load, and the roof area that you're carrying.

Just eyeballing it, and not doing any math, I'd guess the weak point is now the little beams at the feet of the posts that hold up the ends of the trusses. There will be a huge bending moment in the center of those. CB.

I just don't know how to calc load on a parallel truss
Span is 26
Snow load reduced for 45 degree angle is 16 psf
Dead load is 14 psf
Tributary width is 13 feet

I removed the support beams you are talking about so you could see the rest of the structure

Not sure what you mean here. Look at the post that holds up the end of the parallel truss. The beam that post is sitting on will bend in the middle. That's a potential weak spot in your design.



So we're back to my original advice, which is to seek professional help. The stakes are high! CB.

tietje_3,

really,please follow Daiku's adviceand get an engineer involved. We do not want you to end up underneath a pile of timbers thinking that: Had I only..........
Also rearranging your layout and placing posts differently and closer together may simplify things.

As the others have been alluding to, the Ridge beam is easy once you figure out how to support it right back to the ground. Seek some professional advise from an Engineer familiar with Structural design.