Lumber Storage Shed Configuration


Top Grade Lumber company needs a new storage shed and have hired you to specify
the longest span of the shed that be constructed using only 2x8 pieces of lumber.
You have decided to use a "T" cross sectional beam by combining two
2x8 pieces of lumber (at the job site).
What is known:
 The roof needs to withstand a combined dead and live load of 60 lb/ft^{2}.
 The 2x8 "T" beams will be spaced 2 ft on center.
 The width of the shed, W, is not given and can be many more beams wide.
 Local building codes require a factor of safety of 2.0.
 The wood is Douglas Fir with a failure stress of 7,500 psi.
 Two 2x8s are securely glued and nailed together (shear stresses
at joint do not have to be considered).
 Assume the beam is simply supported at each end by the wall structure.
