Design CLT floor and roof panels according to CSA O86-19 and ANSI/APA PRG 320. The easiest way to verify Mass Timber elements for Canadian Limit States Design.
Canada is a global leader in Mass Timber, from the tall wood buildings of Vancouver to the institutional projects of Toronto. However, ensuring compliance with CSA O86 (Engineering Design in Wood) requires navigating complex composite theory and strict vibration limits.
The SPEC Toolbox CLT Calculator is built for the Canadian workflow. It handles the rigorous Limit States Design (LSD) checks required by the National Building Code of Canada (NBCC). Whether you are specifying standard SPF panels or high-performance Douglas Fir, this tool unifies the supply chain into one metric, code-compliant platform.
This tool performs a complete rational analysis of CLT panels under gravity loads, utilizing the Shear Analogy or Gamma Method as permitted by CSA O86. It checks:
1. PRG 320 (The Canadian Standard)
While PRG 320 is shared with the US, Canada uses the Metric stress grades.
Our calculator includes the standard Canadian layups:
2. Limit States Design (LSD)
Unlike the US (which often uses ASD), Canada strictly uses Limit States Design.
The calculator automatically applies the standard load combinations (1.25D + 1.5L) and material resistance factors ($phi$) to give you a clear “Pass/Fail” ratio.
3. Rolling Shear Verification
Rolling shear is often the “Achilles Heel” of CLT.
CSA O86 provides specific shear resistance values for cross-layers. Our tool calculates the shear flow at the neutral axis of every layer, ensuring that the “rolling” stress never exceeds the factored resistance ($v_r$), preventing sudden shear failure.
Factored Resistance ($phi$):
We apply the standard CSA O86 resistance factors:
Modification Factors:
The calculator automatically applies the relevant $K$ factors:
Creep ($K_{creep}$):
For long-term deflection, CSA O86 requires a creep factor.
Yes. SPF is the backbone of the Canadian timber industry. You can select standard “V2” grades which utilize SPF No.1/No.2 lumber, or select custom SPF layups.
We use the vibration design method outlined in the CSA O86 appendices and the CWC Wood Design Manual. This checks the fundamental frequency ($f_n$) and stiffness ($1$ kN deflection) to ensure the floor doesn’t feel “bouncy.”
Yes. The calculator generates a design report referencing the specific clauses of CSA O86-14/19, suitable for submission as part of your structural package.
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