W4 beam load capacity?

[STx]

I'll be building a post frame shop with a steel frame roof so I don't have to use trusses. I'm using a 40' high cube shipping container as one wall and then building the other 3 off of it, planning to end up with a 40 x 40 to start.

Can I use W4x13 for the center support beam? I have them available easily but only in 20' 4" pieces so I'd have to fish a couple together to make the full 40' span. I want clear span underneath so there would be no center support.

Roof will probably be a 3/12 and we don't have snow to worry about so there's no load to speak of, just the roof structure and tin, I just don't want it to sag in the middle. There seem to be some engineers here that really understand beam load capacities so I'm hoping one of you can help.

 

[RedNeckRacin]

I don't think a w4x13 is nearly enough beam. You need to figure out your dead load and live load then you can begin to figure out your distributed loading. This will dictate the minimum size of beam needed. Generally deflection or lateral torsional buckling will limit your beam designs. Introducing a connection into the equation really complicates the problem. I would strongly suggest investing the money into an engineer if you want to be sure it will stand. Connection points are a very unique animal and require some more advanced knowledge of figuring out how to transfer the forces.