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CSA O86:19NBCC 2015CWC Wood Design Manual 2017

Wood Beam

Beam reactions link to your column and footing calculations automatically - change a load once and everything downstream updates. Design wood beams to CSA O86:19 with NBCC 2015 load combinations: factored moment, shear, bearing, and three deflection limit checks for simple and continuous spans.

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What it calculates

The easy to use online Calcs.com Wood Beam Calculator to CSA O86:19 enables you to do quick and powerful design and analysis for simple and continuous timber beams, with unlimited supports and loads. Choose from our library of thousands of common wood sections, or create your own and get instant results with our easy to understand traffic light checks for moment, deflection, and shear.

Code standards

  • CSA O86:19
  • NBCC 2015
  • CWC Wood Design Manual 2017

How it calculates

Structural model and load combinations

The calculator models the beam as a one-dimensional element and computes bending moment, shear, and deflection diagrams under each NBCC 2015 load combination. Loads are entered by type - dead (D), live (L), snow (S), wind (W) - and the calculator automatically generates all governing strength (ULS) and serviceability (SLS) combinations, for example:

  • 1.25D + 1.5L
  • 1.25D + 1.5S + 1.0L
  • 0.9D + 1.5W (uplift check)

Three independent sets of serviceability combinations are generated for short-term (live/snow), long-term (including creep), and simplified DL+LL deflection checks.

Bending moment resistance (CSA O86:19 Cl.7)

Factored bending resistance M_r is computed from the reference bending strength F_b adjusted by a chain of CSA O86:19 factors:

  • K_H - system factor for repetitive-member assemblies
  • K_Scs - service-condition factor for bending
  • K_T - treatment factor
  • K_zbg - size factor for sawn lumber, or volume factor for glulam members

Lateral stability is checked by computing the slenderness ratio C_B = L_e × d / b² for each unbraced segment. Where C_B exceeds the threshold for full resistance, the lateral stability factor K_L is applied. The slenderness ratio must remain at or below 50 per CSA O86:19 Cl.7.5.6.4 - the calculator flags a failure if this limit is exceeded.

moment utilization = M_f / M_r ≤ 1.0

Shear resistance (CSA O86:19 Cl.6.5.4.3)

Factored shear resistance V_r applies the service-condition, treatment, and size adjustment factors to the reference shear strength F_v. For glulam members the calculator uses the CSA O86 simplified shear strength method, which is valid for members with volume under 2 m³. Shear demand is taken at the location of peak shear, which may conservatively be directly over the support rather than at distance d.

shear utilization = V_f / V_r ≤ 1.0

Bearing capacity

For each support, factored bearing demand Q_f is checked against factored bearing resistance Q_r, adjusted for service condition and treatment. A bearing contact area is specified per support; the check is skipped for supports with zero contact area.

Deflection checks (CSA O86:19 Cl.5.4.2 / NBCC Commentary D)

Three independent deflection limits are verified per span:

  1. Live/short-term deflection - governed by short-term serviceability load combinations; checked against a user-defined span/n ratio
  2. Long-term deflection - accounts for creep under sustained loads using the adjusted long-term modulus; checked against a separate span/n ratio
  3. Simplified DL+LL deflection - total dead-plus-live deflection checked against a third span/n limit

An optional absolute deflection limit in mm can be applied alongside any span-ratio limit. The governing deflection ratio per span is reported against each active limit.

Load linking

Support reactions are exported as linked outputs. When this beam is part of a larger project, connected column and footing calculations downstream automatically receive updated reactions whenever the beam inputs change - no manual re-entry of loads required.

Related calculators

Wood Column (CSA O86)→

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Frequently asked questions

What design standard does this calculator use?
The calculator designs wood beams to CSA O86:19 (Limit States Design) with load combinations per NBCC 2015. Species and grade properties are drawn from the CWC Wood Design Manual 2017. Supported product types include sawn lumber, glulam, and SCL (LVL, PSL, LSL).
What are the key inputs?
Key inputs include the wood section (species, grade, and product type from the built-in database), beam plan length, number of plies, service condition (dry or wet), treatment, support layout, loads by type (dead, live, snow, wind), lateral top-flange bracing spacing, and three independent deflection limit ratios.
What checks and outputs does it produce?
The calculator checks factored bending moment resistance (M_f/M_r ≤ 1.0), shear resistance (V_f/V_r ≤ 1.0), bearing capacity at each support, governing live/short-term deflection, long-term deflection, and simplified DL+LL deflection - each against user-defined span ratios and an optional absolute limit. Lateral stability (slenderness ratio ≤ 50) is verified per CSA O86:19 Cl.7.5.6.4.
Can it handle multi-ply beams and glulam?
Yes. Multi-ply (built-up) beams are supported in strong-axis bending with any number of plies. Glulam checks use the CSA O86 simplified shear resistance method, valid for members with volume under 2 m³ - the calculator enforces this limit automatically. LVL and other SCL products from major Canadian manufacturers are included in the section database. Weak-axis bending is supported for single-ply members only.
How do I select a wood section?
Use the section picker to filter by product type (sawn lumber, glulam, SCL), species group, and grade. The calculator loads CSA O86:19 tabulated reference design values automatically. You can also define a custom section by entering cross-section dimensions and manually entering design values if your species or grade is not in the built-in database.
Does this calculator support load linking with column and footing calculations?
Yes - beam reactions link directly to connected column and footing calculations in the same project. When you change a span, load, or section, all downstream calculations update automatically - no manual re-entry of reactions required.

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