AWC Connection Calc 2.4.22

This software provides a mobile-friendly tool for assessing the capacity of fasteners such as single bolts, nails, lag screws, and wood screws in accordance with the 2024 National Design Specification® for Wood Construction (NDS®). It allows users to determine both lateral (single and double shear) and withdrawal capacities for various connection types, including wood-to-wood, wood-to-concrete, and wood-to-steel assemblies.

LIMITS OF USE

SCOPE AND LIMITATIONS

• Connection capacities are derived based on the guidelines specified in the 2024 NDS®. Calculations assume compliance with the following standards:
• Bolts and lag screws conform to ANSI/ASME B18.2.1; wood screws to ANSI/ASME B18.6.1; nails to ASTM F1667.
• Fasteners must be installed in predrilled lead holes in accordance with NDS Chapter 11 procedures.
• They should not be driven forcefully into members using impact tools such as hammers.
• Adjacent members' faces must be in contact during fastener installation.
• Proper edge, end, and spacing distances must be maintained to prevent splitting, per NDS Chapter 11.
• Steel side plates of ¼ inch or greater thickness should meet ASTM A36 requirements; thinner plates should meet ASTM A653 Grade 33 specifications.
• Concrete members must have a compressive strength (f_c') of at least 2500 psi.
• This online calculator does not specifically address multi-fastener configurations; refer to NDS Chapters 10-11 and Appendix E for relevant provisions.
• Connections with fasteners installed at angles to the grain (such as toe-nails) are beyond the scope of this tool; consult NDS Chapters 10-11 for applicable design rules.
• Fasteners subjected to combined lateral and withdrawal loads are not covered; see NDS Chapters 10-11 for guidance.
• Connections involving gaps or non-structural spacer blocks are not supported by this calculator.

GENERAL STRUCTURAL GUIDELINES

The quality of structural timber products and fasteners, as well as the design of load-bearing members and connections, must comply with NDS standards. This calculator is based on the design equations for lateral and withdrawal loads provided in NDS Chapters 10 and 11, along with fastener characteristics detailed in NDS Appendix L. Additional recommendations can be found within the NDS Commentary, Appendices I through N, and Chapters 12-13 concerning connection design principles in wood structures.

RESPONSIBILITY FOR DESIGN

While extensive efforts have been made to ensure the accuracy of this information and its alignment with current engineering practices, neither the American Wood Council nor its affiliates accept responsibility for any specific designs resulting from its use. Users should assume full liability for all applications involving this calculator.

This tool is intended to assist in design evaluation but does not replace the comprehensive guidelines provided by the NDS nor encompass all possible connection types or design options.

The American Wood Council (AWC) is dedicated to promoting a resilient, safe, and sustainable built environment. Through contributing to public policy development, code enforcement, technical standards, and educational initiatives, AWC supports responsible use of wood products. For further information or technical assistance, contact AWC via email at [email protected] or consult regional building code experts affiliated with AWC.