Wood Shear Wall (ASD, NDS 2018)

Designs segmented and perforated wood shear walls to AWC SDPWS 2021 and NDS 2018 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.

This calculator uses an earlier code edition (AWC SDPWS 2021, AWC NDS 2018). It stays available for existing projects. For new designs, check the [Calculator Library](/docs/calculators/us) for the current edition. ## Method & scope | Property | Detail | | ---------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Design standards | AWC SDPWS 2021, AWC NDS 2018 | | Regions | United States | | Who it's for | US structural engineers designing wood shear walls to AWC SDPWS 2021 and NDS 2018, including multi-story residential and light commercial projects with segmented or perforated walls and non-aligned openings. | | What it checks | Lateral system and wall classification, Unit shear demand, Chord force derivation, Chord member design, Holdown selection, Shear wall deflection | #### What it calculates Designs segmented and perforated wood shear walls to AWC SDPWS 2021 and NDS 2018 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, no manual catalog lookup required. Holdown selection now includes HDUE heavy-duty uplift connectors alongside standard HDU products, covering the full range of chord tension forces in multi-story wood-frame structures. #### Calculation method ##### Lateral system and wall classification The calculator classifies the wall as either a segmented shear wall or a perforated shear wall per AWC SDPWS 2021. 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, including segments with openings, participates, with capacity reduced by the percentage of full-height sheathing per SDPWS 2021 Table 4.3.4.2. ##### Unit shear demand For a given story, the applied shear force V (wind or seismic) is divided by the shear-resisting length to obtain the unit shear demand v: * **Segmented method:** v = V / (sum of segment lengths) * **Perforated method:** v = V / (C\_o × L\_total), where C\_o is a function of the ratio of full-height sheathed area to total wall area per SDPWS 2021 Table 4.3.4.2 The unit shear demand is compared against the tabulated allowable unit shear capacity v\_s from SDPWS 2021 Tables 4.3A or 4.3B for the specified sheathing type, fastener schedule, and framing species. ##### Chord force derivation The overturning moment at the base of each wall segment generates axial forces in the boundary chord members, compression at the loaded end and tension at the far end. For a wall of height h and segment length L\_s with unit shear v: **T = C = (v × h × L\_s, N\_gravity × L\_s / 2) / L\_s** Gravity loads from the floor or roof above reduce the net chord tension. For multi-story walls, cumulative chord forces from upper stories are added to the overturning demand at each story, increasing holdown requirements at lower levels. ##### Chord member design The calculated chord tension and compression forces are checked against the ASD capacity of the boundary stud or post per NDS 2018. Tension capacity uses the net cross-sectional area and the reference tensile design value F't adjusted for C\_D, C\_M, C\_t, and C\_F. Compression capacity uses the column stability factor C\_P derived from the stud effective length between floor plates. ##### Holdown selection The required holdown uplift capacity equals the net chord tension force after gravity load offset. The calculator searches the Simpson Strong-Tie holdown catalog, including HDU, HDUE, and PHD series products, and returns the lightest product meeting the required capacity, together with its allowable load at the governing load duration factor C\_D. The minimum post size and fastener schedule are reported to support detailing. ##### Shear wall deflection Total shear wall deflection is computed per SDPWS 2021 Section 4.3.2 as the sum of four components: bending deflection of the chord members, shear deformation of the sheathing panel, nail deformation at the sheathing-to-framing interface, and holdown elongation. The calculated deflection is compared against the inter-story drift limit from ASCE 7 Table 12.12-1. ## 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). ## Common questions AWC Special Design Provisions for Wind and Seismic (SDPWS 2021) for shear wall capacity, combined with NDS 2018 ASD for the chord member and holdown design. Both segmented and perforated shear wall methods are supported. Wall geometry (height and length), sheathing type and thickness, stud species and spacing, applied wind and seismic shear loads, and story level (for multi-story stacking). For perforated walls, opening locations and dimensions are also required. Unit shear demand vs allowable capacity from SDPWS 2021 tables, chord axial loads (compression and tension), holdown anchor force, and overall shear wall deflection. For Simpson Strong-Tie integration, the calculator identifies the required holdown product directly from the Simpson catalog, including HDUE heavy-duty uplift connectors. The segmented method treats only the solid (no-opening) wall segments as shear-resisting elements, requiring holdowns at each segment end. The perforated method uses the full wall length including openings, applying an adjustment factor for opening area, typically reducing holdown requirements and simplifying detailing. Yes. The calculator handles single-story and multi-story configurations. For multi-story walls, cumulative chord loads and overturning from upper stories are accumulated into the design of lower story chords and holdowns. Yes. Applied lateral loads can be linked from an upstream wind or seismic load calculation in the same project. Chord compression forces link downstream to connected column calculations, so when you change wall geometry or loading the chord design updates automatically without re-entry. ## Next steps Complete list of Calcs.com design calculators available for United States projects (AISC, ACI, NDS, ASCE 7, IBC, and related standards). Design wood beams to NDS 2018 (ASD): bending, shear, bearing and deflection. An earlier code edition, kept for existing projects. Design wood columns and studs to NDS 2018 (ASD). An earlier code edition, kept for existing projects. Select Simpson Strong-Tie connectors from the 2021-2023 catalog against NDS 2018 (ASD) allowable loads. An earlier edition, kept for existing projects. Design wood truss and frame members to NDS 2018 (ASD) from analysis forces. An earlier code edition, kept for existing projects. 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. Design segmented and perforated wood shear walls to AWC SDPWS 2021 and NDS 2024 (ASD), with unit shear, chord forces and a holdown match. Basic guide to the US Wood Shear Wall calculator to AWC SDPWS 2021 and NDS 2024, including multi-story shear walls.