Consider Multiply Width for Beam Stability Factor

The Boise Design Engine will always consider the single ply width, NOT the composite width for the stability factor. To accurately compare Boise Cascade's EWP with other EWP manufacturers or dimension lumber, the setting "Consider Multiply Width for Beam Stability Factor" must be set to No.

In MiTek Structure you may notice a difference in Moment capacity between Boise Cascade products and other manufacturers or solid sawn (dimension lumber) products. This is due to a default software setting in version 8.5.2 and older treating multi-ply beams as though they were solid beams. This is only permitted for dimension lumber and other (non-Boise Cascade) LVLs.

In summary:
  • The Boise Design Engine will NOT consider composite width regardless of this setting.
  • To accurately compare Boise EWP with other manufacturers or dimension lumber, change the setting below to “No”.
  • The setting (Job Settings > Design > General Preferences: Consider Multiply Width for Beam Stability Factor) only applies to non-Boise products.
    • Yes uses the full width of the multi-ply member for beam stability analysis.

    • No uses the width of an individual ply for beam stability analysis.


A lack of beam bracing along the span length may cause lateral movement and buckling failure. Multiple ply beams, even properly fastened, will deflect laterally much greater (5⁺ times) than solid beams of the same width. Thus, bending capacity is reduced significantly more than solid beams for unbraced applications. 



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