These may occur in a wood structural member parallel to the grain (end bearing), perpendicular to the grain, or at an angle to the grain.
Bearing Parallel to Grain
The bearing stress parallel to grain ƒg should be computed for the net bearing area.
This stress may not exceed the design value for bearing parallel to grain Fg multiplied by load duration factor CD and temperature factor Ct (Art. 10.5). The adjusted design value applies to end-to-end bearing of compression members if they have adequate lateral support and their end cuts are accurately squared and parallel to each other.
When ƒg exceeds 75% of the adjusted design value, the member should bear on a metal plate, strap, or other durable, rigid, homogeneous material with adequate strength. In such cases, when a rigid insert is required, it should be a steel plate with a thickness of 20 ga or more or the equivalent thereof, and it should be inserted with a snug fit between abutting ends.
Bearing Perpendicular to Grain
This is equivalent to compression perpendicular to grain. The compressive stress should not exceed the design value perpendicular to grain multiplied by applicable adjustment factors, including the bearing area factor (Art. 10.5.11). In the calculation of bearing area at the end of a beam, an allowance need not be made for the fact that, as the beam bends, it creates a pressure on the innr edge of the bearing that is greater than at the end of the beam.
Bearing at an Angle to Grain
The design value Fg for bearing parallel to grain and the design value for bearing perpendicular to grain Fc differ considerably. When load is applied at an angle