Limit States Design (LSD) tool for structural timber connections.
The CSA O86 Screw Calculator is a sophisticated engineering tool designed to calculate the Factored Lateral (Nr ) and Withdrawal (Pr ) resistance of dowel-type fasteners. This tool helps structural engineers optimize connections in Canadian Lumber, Glulam, and Mass Timber (CLT) with strict adherence to the CSA O86-19 standard.
The days of manually iterating through the multi-mode Yield Limit Equations (CSA O86 Clause 12.6.6) are over. The SPEC Toolbox calculator handles the complex interaction between fastener bending yield strength (fy ) and the embedment strength (fh ) of timber members instantly.
We solve for all failure modes simultaneously to identify the controlling Factored Lateral Resistance (Nr ):
Our engine automatically adjusts embedment strength (fh ) based on specific gravity (G) and load direction, ensuring accurate results for both Parallel to Grain and Perpendicular to Grain loading.
Lateral capacity is only half the equation. Our calculator provides a complete analysis of axial tension forces.
As mass timber adoption grows across Canada, engineers need tools that go beyond standard lumber. SPEC Toolbox is optimized for Cross-Laminated Timber (CLT).
Fasteners in CLT (CSA O86 Clause 8)
Designing connections in CLT requires adherence to specific provisions in CSA O86-19. Our calculator allows you to:
Inclined Screw Technology
Maximize connection stiffness by utilizing inclined screws (45°). Our tool supports the calculation of screws loaded in combined shear and withdrawal, a common detailing practice in Canadian mass timber projects for Timber-Concrete Composites (TCC) and beam hangers.
The basic unit strength is rarely the final number. We automate the application of all applicable Modification Factors to determine the final resistance:
Yes. For proprietary screws, we utilize the design values and equivalent specific gravities derived from CCMC (Canadian Construction Materials Centre) evaluation reports or relevant ICC-ES data converted to Limit States Design.
Yes. In addition to generic ASME lag screws, you can select from major suppliers like Rothoblaas, MyTiCon, and others. The calculator automatically updates the bending yield strength (fy ) and root diameters based on the manufacturer’s technical data.
The calculator assumes standard installation per CSA O86 Clause 12.5. If pre-drilling is required for the specific fastener diameter or wood density (e.g., Douglas Fir-Larch), the interface will note the requirement to ensure the calculated resistance (Nr ) is valid.
Steel-to-timber dowel and bolt connections look simple on drawings, but these joints are where “clean” global actions become messy local demands, especially when the connection must carry moment, shear, and…
Read More
MELBOURNE, Australia: SPEC Toolbox (formerly CLT Toolbox), the construction technology platform automating complex engineering for sustainable building materials, has successfully raised $3 million in a Pre-Series A funding round. The…
Read More
Designing screwed timber connections is a critical aspect of modern timber construction, where screws are increasingly used for their efficiency, speed of installation, and structural performance. With the growing adoption…
Read More
As mass timber construction continues to gain prominence in the building industry, driven by its sustainability credentials and structural capabilities, the demand for more elaborate and high-strength connections has increased….
Read More
Why This Ribbed Deck Blog Matters Ribbed decks are an innovative solution in modern timber construction, offering a combination of strength, stiffness, and material efficiency. However, engineers often face challenges…
Read More
