AWC Connection Calc2.4.22 - App Store

Provides users with a mobile approach to calculating capacities for single bolts, nails, lag screws and wood screws per the 2024 NDS. Both lateral (single and double shear) and withdrawal capacities can be determined. Wood-to-wood, wood-to-concrete, and wood-to-steel connections are possible.

LIMITS OF USE

SCOPE AND LIMITATIONS
Connection capacities are calculated on the basis of design provisions in the 2024 National Design Specification(R) for Wood Construction (NDS(R)). The calculated capacities are based on the following assumptions and conditions:

. Bolts and lag screws must meet the requirements of ANSI/ASME B18.2.1, wood screws must meet the requirements of ANSI/ASME B18.6.1, and nails must meet the requirements of ASTM F1667.
. Bolts, lag screws and wood screws must be installed in predrilled lead holes in accordance with the provisions of NDS Chapter 11.
. Bolts, lag screws and wood screws must not be forcibly driven into connection members with a hammer or other impact device.
. The faces of adjacent connection members are brought into contact when fasteners are installed.
. Adequate edge distances, end distances and spacing must be provided for all fasteners to prevent splitting of wood connection members, in accordance with NDS Chapter 11.
. Steel side plates with thickness of 1/4 in. or greater must meet the requirements of ASTM A36, and steel side plates with thickness less than 1/4 in. must meet the requirements of ASTM A653, Grade 33.
. Concrete connection members must have compressive strength (fc') of at least 2500 psi.
. The on-line Connection Calculator does not specifically address multiple-fastener connections. See NDS Chapters 10-11 and NDS Appendix E for applicable design provisions.
. The on-line Connection Calculator does not address fasteners installed at an angle to grain (e.g., toe-nails). See NDS Chapters 10-11 for applicable design provisions.
. The on-line Connection Calculator does not address fasteners subjected to combined lateral and withdrawal loading. See NDS Chapters 10-11 for applicable design provisions.
. The on-line Connection Calculator does not address connections with gaps or non-structural spacer blocks between members.

GENERAL STRUCTURAL GUIDELINES
The quality of structural wood products and fasteners and the design of load-supporting members and connections shall conform to provisions of the NDS. The on-line Connection Calculator is based on design equations for lateral loading and withdrawal loading specified in NDS Chapters 10 and 11, along with fastener characteristics specified in NDS Appendix L. The NDS Commentary, NDS Appendices I through N, and NDS Chapters 12-13 provide additional guidelines regarding the design of connections in wood structures.

RESPONSIBILITY FOR DESIGN
While every effort has been made to insure the accuracy of the information presented, and special effort has been made to assure that the information reflects the state-of-the-art, neither the American Wood Council nor its members assume any responsibility for any particular design prepared from this on-line Connection Calculator. Those using this on-line Connection Calculator assume all liability from its use.

This Connection Calculator is not meant to be a replacement for the NDS and does not encompass all of its design options.

The American Wood Council
On behalf of the industry it represents, AWC is committed to ensuring a resilient, safe and sustainable built environment. To achieve these objectives, AWC contributes to the development of sound public policies, codes and regulations that allow for the appropriate and responsible manufacture and use of wood products. We support the utilization of wood products by developing and disseminating consensus standards, comprehensive technical guidelines and tools for wood design and construction, as well as providing education regarding their application. Contact AWC via email: info@awc.org or connect with one of AWC’s regional building code experts.

Version History FIXED: Metal Hardware Nail Sizes was removed by AOT linker 2.4.22 04/26/2025 FIXED:
- Bolts should not be included in Pull-Through Loading
- Other ring-shank nails redundant with Common / Box / Sinker nails 2.4.21 04/17/2025 FIXED : Lag Screws are not applicable to Pull Through Connections 2.4.20 04/16/2025 FIXED: Pull through analysis show input error but does not indicate which input is at fault. 2.4.19 04/15/2025 FIX: Occasional error message appearing at app start 2.4.18 04/10/2025 FIXED: Penetration length errors 2.4.17 03/26/2025 FIXED: Washers included in withdrawal penetration length when they shouldn't be 2.4.16 02/28/2025 NEW:
- Invalid fasteners are filtered from input choices

FIX :
- Wrong length calculated for nails in some scenarios
- Error message shown when switching from Lateral to Withdrawal 2.4.14 02/27/2025 NEW:
- Invalid fasteners are filtered from input choices

FIXED:
- Not using reduced diameters in calculations for Lag Bolts when reduced diameter is selected
- Failure to apply Table 12.3.1B, Note 1 for calculating reduction term
- Incorrectly using Dowel Bearing Diameter instead of Nominal Diameter for Fe values used in Lateral Analyses 2.4.12 02/23/2025 FIXED:
- Side Member Thickness selection not shown when switching between STEEL and an another Side Member Material Type
- WoodScrew Penetration Length is zero
- Length or Size values not consistently selected when switching fastener parameters

NEW:
- More detailed error reports 2.4.7 02/02/2025 FIXED: Steel as a side member material is not available for Withdrawal connection loading 2.4.5 01/26/2025 NEW: In session error handling and reporting 2.4.2 01/23/2025 FIXED: Steel Side Member remains selected after switching from Lateral to Withdrawal or Pull-Through connection type. 2.4.1 01/21/2025 FIXED:
- Fasteners > 0.25" diameter appearing for sheathing
- Grain Angle setting resetting when changing other settings
- lb/in units shown as /in in some cases
- wrong formula for Lag Screw withdrawal in Analysis Parameters notes
- Lag and Wood Screws use wrong value for thread penetration
- Reversed usage of Dr vs. D in lateral bolt calculation
UPDATED:
- Main vs Side member descriptions
NEW:
- Error report handling
- Analysis Parameters Section (collapsed to minimize verbosity) 2.4.0 01/14/2025 FIX: Intermittent UI issue when editing a cell 2.2.1 11/21/2024 1) Updated to the 2021 NDS
2) New: now supporting Pull-Through analyses
3) Three types of Ring Shank nails supported 2.2.0 11/10/2024 Additional diagnostics 2.1.51 07/01/2020 Fixed:
- Crash when trying to print help screen
- Toggling some analysis settings on/off may cause other analysis settings options to disappear 2.1.50 03/30/2020 Fixed:
- Toggling some analysis settings on/off may cause other analysis settings options to disappear 2.1.49 03/18/2020 Fixed:
- Crash when printing contents of help screen; 2.1.48 03/16/2020 - Fixed: A number user interface bugs.
- New app icon.
- Intermittent crash when navigating. 2.1.47 03/07/2020 - Fixed: A number user interface bugs.
- New app icon. 2.1.46 02/26/2020 Fixed:
- Intermittent crash when selecting Lag Screw fastener for the first time;
- [Calculate] button is not noticeable enough;
- Unnecessary memory consumption;
- Intermittent crash when selecting item from popup list; 2.1.43 02/13/2020 Fixed: 
- Wrong values calculated when Load to Grain angle is zero;
- & showing up in analysis type picker;

New:
- Ability to disable rounding of DBS to nearest 50 psi; 2.1.42 01/28/2020 Fixed:
- Crash when trying to calculate LagScrew after [Reset]
- Can copy Toast information by long press;
- Intermittent crash on help viewer
- Intermittent crash on clicking [Done] in notes viewer;- Export menu is blank on second appearance;
- Crash when entering expression with dangling operator (ex: "20 ÷ [Done]");
- Occasionally, operands in expression editor are not vertically justified correctly; 2.1.41 11/27/2019