Defects in material or workmanship, which result in failure under long term loading conditions.
Shear failures are prevalent near the ends, and at mid-depth of glued laminated beams.
This is primarily due to the fact that lessor grade lumber is allowed in these areas. Of course, excessive load is often the most common cause of shear failures. Impact from forklifts. This often occurs in warehouse operations where the beams are damaged due to the driver's impaired visibility or carelessness. Exposure to such elements, as extreme heat, moisture, or acqustic chemicals.