What it checks
The module designs sawn lumber, glulam, or LVL/PSL/LSL wood beam sections. It performs NDS 2018 allowable stress design (ASD) checks for bending, shear, bearing, and biaxial conditions. The engine applies load duration factors (C_D) per load case and evaluates deflection limits for each member.Inputs
- Section Properties - Width (in), depth (in), nominal size class, and catalogue-specific factors like C_F or C_V.
- Material Data - Reference bending strength (F_b), shear strength (F_v), compression perpendicular to grain (F_c⊥), and reference modulus (E_min).
- Geometry - Span length (ft), laterally unsupported length (ft), and notch dimensions (in) if applicable.
- Load Combinations - Service and strength combination factors, including dead, live, and other load case multipliers.
- Support Conditions - Bearing length (in) and the reference F_c⊥ of the supporting member for bearing checks.
What it reports
- Bending Stress - Calculated stress compared against the adjusted allowable bending stress, applying C_F for sawn lumber or C_V for glulam.
- Shear Stress - Calculated shear stress compared against the adjusted allowable shear stress, including notch adjustments if present.
- Bearing Stress - Perpendicular-to-grain stress compared against the allowable bearing stress, applying the C_b area factor where bearing length is under 6 inches.
- Lateral Stability - Stability factor C_L calculated based on unsupported length and section dimensions, applied to the bending capacity.
- Deflection - Service combination deflection compared against project-specific serviceability limits, optionally using half-dead load for total deflection.
- Governing Combination - The specific load combination that produces the worst-case stress or deflection at each station.
Code references
The engine cites NDS 2018 §3.3, §3.4, §3.9.1, and §3.10 for wood member checks, including §3.3.3 for lateral stability and §3.10.4 for bearing area factors. It also references ASCE 7-22 §2.3 and §2.4 for load combinations, with fallbacks to ASCE 7-16 §2.3.1 and §2.4.1 if specific combination configurations are not provided.Limits
The module does not apply load duration factors to bearing checks, as per NDS Commentary §3.10. It assumes the input provides pre-computed C_F and C_L factors for sawn lumber stability. Deflection checks use service combinations only, not ad-hoc sums of basic load cases. Results are engineering aids; the engineer of record is responsible for the design.Try it free in your browser
The Wood Beam calculator runs this module's engine with no install and no signup.