United StatesAWC SDPWS 2021AWC NDS 2024
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
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.
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
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.
Webinar: Calculating Wood Shear Wall Capacity
Holdowns in Shear Walls
Common questions
What design standards does this calculator use?
What design standards does this calculator use?
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.
What are the key inputs?
What are the key inputs?
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.
What does the calculator check and output?
What does the calculator check and output?
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.
What is the difference between the segmented and perforated methods?
What is the difference between the segmented and perforated methods?
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.
Can this calculator handle multi-story shear walls?
Can this calculator handle multi-story shear walls?
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.
Does this calculator support load linking with connected calculations?
Does this calculator support load linking with connected calculations?
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
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2-Story Perforated Shear Wall Worked Example
Worked example: a two-story wood shear wall designed with the perforated method to AWC SDPWS 2021 and NDS 2024.
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US Wood Shear Wall - Basic Guide
Basic guide to the US Wood Shear Wall calculator to AWC SDPWS 2021 and NDS 2024, including multi-story shear walls.