Design complex timber connections to CSA O86-19/24. Analyze Shear, Axial, and Moment actions on multi-bolt groups with automated Limit States Design (LSD) checks.
Canadian timber design is unique in its rigorous treatment of brittle failure modes. While a bolt might yield ductilely, the timber around it can split suddenly—a risk that CSA O86 addresses with complex “Row Shear” and “Group Tear-out” equations.
The SPEC Toolbox Dowel & Bolt Module handles this complexity automatically. Whether you are designing a glulam truss node or a heavy timber beam splice, this tool runs the full CSA O86 Limit States Design (LSD) verification. It optimizes your connection for both ductile yield (steel failure) and brittle fracture (wood failure), ensuring a safe and efficient design.
This module utilizes a dynamic visual engine to optimize dowels, bolts, and steel plates. It automates the iterative checks required by the National Building Code of Canada:
1. Yield Limit Theory (Automated)
CSA O86 requires checking multiple yield modes to find the “Unit Lateral Strength” ($n_u$).
Our calculator runs the full matrix:
2. Combined Actions (Moment + Shear)
Standard CSA tables don’t tell you how to handle a moment-resisting knee connection.
Our module uses a Rational Analysis (Elastic Method). It resolves the applied Moment, Shear, and Axial forces into a resultant vector for every bolt. It then checks this resultant against the bolt’s capacity at that specific angle to grain ($N_{r,\theta}$), ensuring the “corner bolts” don’t fail.
3. The Group Effect ($J_G$)
In a long row of bolts, the load is not shared equally.
The calculator calculates the Group Effect Factor ($J_G$) based on the number of fasteners per row, the stiffness of the members, and the ductility of the connection. This prevents the dangerous overestimation of capacity in large tension splices.
Factored Lateral Resistance ($N_r$):
$$N_r = \phi \cdot N_u \cdot n_F \cdot K_D \cdot K_{SF} \cdot K_T$$
The tool automates the “K-factor” stack:
Brittle Failure ($PR_r$, $PG_r$):
CSA O86 requires checking that the wood block doesn’t tear out before the bolts yield.
Row Shear: Checks shear failure along two planes for each row of bolts.
Group Tear-out: Checks the tearing of the whole block of wood surrounding the group.
Yes. For Steel-to-Timber connections, the tool checks the Steel Plate Bearing and Tensile Yield capacity, using the relevant CSA S16 (Steel Design) provisions where applicable to the interface.
This module focuses on Dowels and Bolts. Glulam Rivets are a distinct fastener type with their own unique physics and are handled in a separate module (coming soon).
Yes. If your end distance is less than the standard requirement but within the “minimum” allowed, the tool automatically applies a reduction factor to the resistance, allowing you to squeeze connections into tight spaces.
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