of Pine and SpruceStructural wood is normally graded with a strength grading machine. See picture. The strength grading machine measures the strength of each piece of wood. Strength grades C18 andC24 are normally used for timber formwork beams, roof trusses and similar.
Example: C36 wood has a bending strength of 36 MPa, which is 360 kg/cm2, the same as high grade concrete. Wood resists both tension and compression. But concrete must be reinforced with steel to resist tension!
|E – modulus Mpa||7000||9000||11000||12000||13000||14000|
STRENGTH GRADED WOOD IS NEEDED FOR THESE STRUCTURES:
Form for a bridge. The wood is of strength class C24. Hall with pillars and beams of laminated glued wood of strength class C14-C40. Wood of strength class C24 for rooftrusses. Joints with nailplates. T & G spruce panels.