Wood Connectors (ASD, NDS 2018 / C-C-2023)
Run the calcBrowse the full Simpson Strong-Tie 2021-2023 Wood Construction Connectors Catalog with end reactions linked directly from your Wood Beam calculations. Checks downward shear and uplift demand against NDS 2018 ASD tabulated allowable loads for joist hangers, top-flange hangers, and post connectors, with CD load duration factors applied and fastener schedules reported.
This calculator uses an earlier code edition (Simpson Strong-Tie Wood Construction Connectors Catalog 2021-2023). It stays available for existing projects. For new designs, check the Calculator Library for the current edition.
Method & scope
Calculation method
Connector lookup and compatibility filtering
The calculator begins by filtering the Simpson Strong-Tie 2021-2023 catalog to connectors compatible with the specified joist or header member. Compatibility is based on member nominal dimensions (b × d), the number of plies, and the supporting member species (DF, HF, SP, or SPF). Face-mount hangers (LUS, IUS, HU, HUC, HHUS families) and top-flange hangers (PF, WP families) are treated as separate connector types with their own catalog lookup tables. For engineered lumber, glulam, Parallam PSL, TimberStrand LSL, and LVL, the calculator identifies connectors sized to the actual member width and depth and applies manufacturer allowable loads for the engineered wood product directly from the catalog.Load combination and demand
Applied loads are entered as unfactored loads by type: dead (D), floor live (L), roof live (Lr), snow (S), and wind downward and uplift. The calculator evaluates all applicable ASD load combinations per NDS 2018 Appendix B and identifies the governing combination for downward shear and uplift separately. The CD load duration factor is applied to the catalog allowable loads consistent with ASD practice. CD is determined by the shortest-duration load type in the governing combination:- D only: CD = 0.90
- D + L (floor): CD = 1.00
- D + S: CD = 1.15
- D + Lr or D + W (downward): CD = 1.25
- D + W (uplift): CD = 1.60
Capacity check
For each direction (downward shear and uplift), the check confirms: Demand ≤ CD × (Catalog Allowable Load) The demand-to-capacity ratio (DCR) is reported for both directions. The connector passes when DCR ≤ 1.0 in every direction checked. Where the catalog lists separate allowable loads for different supporting species (DF/SP vs. HF/SPF), the calculator applies the value corresponding to the specified supporting species input.Multi-ply members
For joist assemblies with more than one ply, the calculator identifies connectors in the HU-n and HUC-n families that explicitly support the required ply count. Allowable loads for multi-ply connectors are taken directly from the catalog rows for that ply configuration, not derived by multiplying single-ply values by the ply count. The fastener schedule output lists the minimum and maximum nail requirements for each face of the connector as stated in the catalog. Nail specifications are given as count × diameter × length.Linked loads from beam calculations
When the connector check is linked to an upstream Wood Beam (ASD) calculation via the load-linking mechanism, the beam’s end reaction at the relevant support is passed directly as the connector’s applied load. The joist member dimensions and species are also inherited from the beam calculation, pre-populating inputs automatically. Any update to the beam geometry or loading propagates to the connector check without manual re-entry.How to use it
1
Open the calculator
Open it from Run calc in the About this calculator panel above.
2
Enter your inputs
Work through the input sections from top to bottom. Click any input label to see its reference explanation, clause, conditions and assumptions. See Checks, References, Conditions and Assumptions.
3
Review the results and export
Check the utilization of each governing check in the summary, then export a PDF report. See Views and Export.
Common questions
What connectors does this calculator cover?
What connectors does this calculator cover?
The calculator covers joist hanger and header hanger families from the Simpson Strong-Tie 2021-2023 Wood Construction Connectors Catalog, including face-mount hangers (LUS, IUS, HU, HUC, HHUS series), top-flange hangers (PF, WP series), and heavy post hangers (U, LSSJ series). Post bases and holdowns are supported as separate connector types within the same calculator.
What are the key inputs?
What are the key inputs?
Connector type and designation (selected from the catalog lookup), joist or header member dimensions and species, supporting member width and depth, wood species and moisture service conditions, and applied concentrated loads broken out by load type (D, L, Lr, S, W). Loads can be entered manually or linked directly from a Calcs.com Wood Beam calculation.
What does it check and output?
What does it check and output?
The calculator compares applied loads against the NDS 2018 ASD tabulated allowable loads from the Simpson Strong-Tie catalog for downward shear, uplift, and lateral (where applicable). It outputs a pass/fail for each direction, the governing load combination, the demand-to-capacity ratio, required fastener schedule, and connector dimensions. All allowable loads include the appropriate CD load duration factor.
Can I link loads directly from a beam calculation into this connector check?
Can I link loads directly from a beam calculation into this connector check?
Yes. If your joist or header has been designed in a Calcs.com Wood Beam (ASD) calculation, you can link that calc directly, the connector check reads the beam’s end reactions automatically. When the beam calculation is updated, the connector check recalculates without any manual data entry. This load-linking is the intended workflow for full load-path documentation.
How do I select the right connector when multiple options pass?
How do I select the right connector when multiple options pass?
The calculator displays all catalog options compatible with your member dimensions and supporting species. When multiple connectors pass, compare demand-to-capacity ratios for downward shear and uplift to find the connector with the lowest excess capacity. Also compare fastener schedules, some connectors require more nails for the same allowable load. For multi-ply members, confirm the connector’s fastener limits accommodate the required ply count.
Next steps
Calculator Library
Complete list of Calcs.com design calculators available for United States projects (AISC, ACI, NDS, ASCE 7, IBC, and related standards).
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