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# Design a Wood Shear Wall (ASD) to NDS 2024
> Design segmented and perforated wood shear walls to AWC SDPWS 2021 and NDS 2024 (ASD), with unit shear, chord forces and a holdown match.
Designs segmented and perforated wood shear walls to AWC SDPWS 2021 and NDS 2024 ASD. Enter wall geometry, sheathing, studs, and per-story lateral loads to get governing wind and seismic unit shear, chord tension and compression forces, and a Simpson Strong-Tie holdown match. Story shears link from wind and seismic analyses and chord forces link to connected column calculations.
## Method & scope
| Property | Detail |
| ---------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Design standards | AWC SDPWS 2021, AWC NDS 2024 |
| Regions | United States |
| Who it's for | US structural engineers designing wood shear walls to NDS 2024 (ASD). |
| What it checks | Lateral system and wall classification, Unit shear demand, Chord loads (SDPWS 2021 Chapter 4.3), Chord tension design (NDS 2024 Section 3.8), Chord compression and bearing (NDS 2024 Sections 3.7 and 3.10), Holdown selection |
#### What it calculates
US structural engineers resisting wind and seismic story shears in light-frame wood buildings, designed to the current NDS 2024 and SDPWS 2021 ASD. Story shears link from wind and seismic analyses, and chord forces link to connected column calculations, so demands update as loads change. Segmented and perforated walls, single- or multi-story.
Designs are verified against the strength increases in footnote 2 of Table 4.3A of AWC SDPWS, out of beta for defensible use.
#### Calculation method
##### Lateral system and wall classification
The calculator classifies the wall as either a segmented or a perforated shear wall per AWC SDPWS 2021 Cl 4.3.2. In the segmented method, only full-height segments without openings contribute to lateral resistance and each segment requires a holdown at each end. In the perforated method, the entire wall length participates, with capacity reduced by a shear capacity adjustment factor that is a function of the full-height sheathing ratio per SDPWS 2021 Chapter 4.3.
##### Unit shear demand
For a given story, the applied wind or seismic shear force is divided by the shear-resisting length to obtain the unit shear demand:
* **Segmented method:** the sum of the full-height segment lengths is used.
* **Perforated method:** the full wall length is used together with the shear capacity adjustment factor.
The unit shear demand is compared against the tabulated allowable unit shear for the specified sheathing, nail pattern, and sheathed sides. Seismic loads are assumed to already include the effect of wall self-weight; self-weight is counted only in the gravity load that restores the wall.
##### Chord loads (SDPWS 2021 Chapter 4.3)
The overturning moment at the base of each segment generates axial forces in the boundary chords: compression at the loaded end and tension at the far end. When calculating chord tension, the full dead load on the wall panel is taken to act as a restoring moment. When calculating chord compression, only the load tributary to the chord studs is applied, with the remainder carried by field studs. For multi-story walls, cumulative chord forces from upper stories are added at each lower story.
##### Chord tension design (NDS 2024 Section 3.8)
Chord tension is checked against the ASD tension capacity of the boundary studs on the net section per NDS 2024 Section 3.8, with the reference tension value adjusted for load duration, wet-service, temperature, and size factors.
##### Chord compression and bearing (NDS 2024 Sections 3.7 and 3.10)
Chord compression is checked against the axial capacity per NDS 2024 Section 3.7, using gross section properties and the column stability factor derived from the stud elastic modulus (Section 2.3) and effective length between plates. Bearing perpendicular to the stud is checked per NDS 2024 Section 3.10.
##### Holdown selection
The required holdown uplift capacity equals the net chord tension after the gravity load offset. The calculator searches the Simpson Strong-Tie holdown catalog, including HDU, HDUE, and PHD series products, and returns a product meeting the required capacity at the governing load duration, together with the minimum post size to support detailing.
## How to use it
Open it from **Run calc** in the About this calculator panel above.
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](/docs/running-calculations/checking-results/checks-references-conditions-assumptions).
Check the utilization of each governing check in the summary, then export a PDF report. See [Views and Export](/docs/running-calculations/exporting-reports/views-and-export).
#### Webinar: Calculating Wood Shear Wall Capacity
#### Holdowns in Shear Walls
## Common questions
AWC Special Design Provisions for Wind and Seismic (SDPWS 2021) for shear wall capacity and chord loads, combined with NDS 2024 ASD for the chord member design and bearing. Both segmented and perforated shear wall methods are supported. This is the NDS 2024 edition; an NDS 2018 version is also available.
Wall geometry (story height, total wall length, number of stories), sheathing and nail pattern, sheathed sides, blocking at panel edges, stud size, grade and spacing, wall self-weight, and the design spectral response acceleration for seismic. For perforated walls, opening locations and dimensions are also entered.
Governing wind and seismic unit shear demand against SDPWS 2021 tabulated capacity, chord tension and compression loads, chord member design to NDS 2024, bearing perpendicular to the stud, and the required Simpson Strong-Tie holdown. Holdown selection covers HDU, HDUE, and PHD series products with the allowable load at the governing load duration.
The segmented method treats only the full-height wall segments without openings as shear-resisting, with a holdown at each segment end. The perforated method uses the full wall length including openings, applying a shear capacity adjustment factor based on the full-height sheathing ratio per SDPWS 2021 Chapter 4.3, which typically reduces holdown requirements.
Yes. Single-story and multi-story configurations are supported. For multi-story walls, the wall panel between each floor is assumed identical, and cumulative chord loads and overturning from upper stories accumulate into the chord and holdown design of the lower stories.
Yes. Applied lateral loads can be linked from an upstream wind or seismic analysis in the same Calcs.com project, and chord compression forces link downstream to connected column calculations. When wall geometry or loading changes, the chord design and holdown selection update automatically without re-entry.
## Next steps
Design wood beams to NDS 2024 (ASD): bending, shear, bearing and three deflection limits, with multi-ply and flitch plate options.
Design wood columns and studs to NDS 2024 (ASD), with load linking from beams and a database of US wood sections.
Design wood truss chords and frame members to NDS 2024 ASD. Combined axial and biaxial bending per Eq. 3.9-3, stability factor Cp, all adjustment factors.
Worked example: a two-story wood shear wall designed with the perforated method to AWC SDPWS 2021 and NDS 2024.
Design a single-story wood shear wall to AWC SDPWS 2021 and NDS 2024 with the Wood Shear Wall (ASD) calculator.
Basic guide to the US Wood Shear Wall calculator to AWC SDPWS 2021 and NDS 2024, including multi-story shear walls.
