Wood shear wall

A wood structural panel shear wall to AWC SDPWS 2021 Section 4.3, with the ASCE 7-22 load factors for wind and seismic. One calculation covers one story of a wall line: a segmented wall (one or more full-height segments) or a perforated wall, sheathed on one or both faces, with the overturning of the stories stacked above.

Source note. SDPWS 2021 itself is not yet on file at ILX Studio (AWC offers it view-only). The SDPWS 2021 design factors (4.1.4) and a part of Table 4.3A (vn and Ga of 15/32 in rated sheathing with 8d and 10d nails and of 15/32 in Structural I with 8d nails) are confirmed by the free published examples listed under Verification examples; the other table rows and the provisions marked "[verify]" in the steps will be re-checked against the document. Where you need certainty now, choose Nominal unit shear: Entered and type the values from your copy of the table.

Inputs of the wood shear wall #

• Sheathing: panel grade (Structural I or rated sheathing), thickness and nail (6d, 8d or 10d common), the edge nail spacing (6, 4, 3 or 2 in), one or both faces. The framing species sets G (NDS Table 12.3.3A); for species other than Douglas Fir-Larch and Southern Pine the capacities are multiplied by 1 − (0.5 − G), never more than 1.0. The panel type picks the OSB or plywood column of Ga (4-ply or more plywood and composite panels: Ga × 1.2), and framing wetter than 19 % at fabrication halves Ga. Entered replaces the table: vs, vw and Ga of the whole wall (both faces), before the species factor; the seismic check uses vn = 1.4 vs (SDPWS 2021 tabulates one vn equal to the former vw).
• 3/8 and 7/16 in panels: SDPWS Table 4.3A permits the 15/32 in values when the studs are at 16 in o.c. or the panels run across the studs (used by the AWC and WoodWorks examples below). The module has no switch for it: pick the 15/32 in row of the same grade and nail in that case.
• Wall: the wall type, the height h and the length bs of each full-height segment. For a segmented wall you choose how the story shear is shared: in proportion to each segment's adjusted capacity, or to its stiffness (equal top deflection by Eq. 4.3-1, with the anchorage slip). For a perforated wall enter the total length Ltot and the openings (width × height).
• Loads: the wind and seismic story forces at the top of this wall, and the forces of any stories stacked on it (same segments; each acts at the top of its story). ASCE 7-22 forces are strength level (W, QE); choose ASD level if you enter 0.6W and 0.7ρQE. The dead load on the wall resists overturning. ρ (ASCE 7-22 12.3.4) and SDS (vertical seismic Ev = 0.2SDS D, 12.4.2.2) are inputs.
• Chords and hold-downs: the chord centroid from each segment end (moment arm d = bs − 2 × offset), the chord E and area A, the anchorage slip Δa (hold-down, rod, shrinkage and crushing, from the manufacturer) and the hold-down capacity in the method's terms (0 reports the force only).
• Drift and deflection: Cd and Ie (ASCE 7-22 Tables 12.2-1 and 1.5-2), the allowable story drift ratio (Table 12.12-1, 0.020 prefilled), the serviceability wind factor and an optional wind deflection limit h / n.
• Code options: the aspect ratio factor for segments with h/bs > 2: SDPWS 2021 (1.25 − 0.125 h/bs, wind and seismic) or, for a project still under SDPWS 2015, 2bs/h for wind and seismic (as the AWC 2015/2018 design examples apply it); with the 2015 rule a perforated wall also counts each segment over 2:1 with 2bs/h of its length.

Auto-design (editor toolbar) varies the sheathing and nail (Table 4.3A row), edge nail spacing and one or two faces. Objectives: lowest cost index (sheathing + nails). Every other input is kept; see Auto-design.

Checks performed #

Drawings #

The drawing sheet (Drawing sheet / DXF buttons, and the report appendix) shows the shear wall elevation of the story designed: the full-height segments (marked SW-1, SW-2 ... with the shear wall cross) or the perforated wall with its openings (O-1, O-2 ...), the stories above as a dashed outline, the story forces at each level, the hold-downs at the ends with net uplift labelled with the tension T, the sheathing and edge nailing callout, and the segment lengths and story heights. The unit shear of each segment, the opening sizes and the largest hold-down tension are in the design summary. The distance between segments, the opening locations, the hold-down device, end posts, sill anchorage and collectors are not part of the calculation; the sheet notes say so.

Limitations #

• Blocked wood structural panel sheathing of Table 4.3A only. Unblocked walls (Cub), gypsum, fiberboard, particleboard and lumber sheathing (Tables 4.3B to 4.3D) are not offered; use Entered with your own values only for wood structural panels.
• Force transfer around openings (4.3.5.2) is not covered; a wall with openings is either segmented or perforated.
• Stories above stack on the same segments; a perforated wall is designed one story at a time.
• The anchorage slip Δa is a constant entered value (not computed from the hold-down force).
• Not checked: chord / end-post compression and bearing, sill plate anchor bolts and plate washers, collectors, the foundation.
• Confirmed from published examples (2026-11-01): the SDPWS 2021 factors 2.0 / 2.8 and 0.80 / 0.50 (4.1.4), vn of 15/32 in Structural I 8d at 3 in (1,540 plf, Ga 24 kips/in OSB), of 15/32 in rated sheathing 10d at 6 / 4 / 2 in (Ga 22 / 30 / 52 kips/in OSB) and 8d at 6 and 4 in, Eq. 4.3-1, Cd δ / Ie drift, and the SDPWS 2015 2bs/h rule for wind as well as seismic. Still [verify] until SDPWS 2021 is on file: the other Table 4.3A rows, the footnote numbers (species, Ga and framing), the dissimilar-faces rule (4.3.3.2), the SDPWS 2021 aspect ratio factor 1.25 − 0.125 h/bs (4.3.4.2), the SDPWS 2021 perforated wall equations, ΣLi and limits (4.3.5.3), the detailing rules (4.3.7).
• From NDS 2024 (on disk) the module takes only the framing specific gravity G (Table 12.3.3A; Redwood corrected to G = 0.37 at verification, which lowers its species factor from 0.94 to 0.87) and the common nail dimensions (Table L4); both are confirmed. NDS 2024 does not contain the SDPWS provisions.

Verification examples #

Published worked examples, all free from their publishers (research/sources/design_examples):

• WoodWorks, Five-Story Light-Frame Wood Structure over Podium, Design Example, 2nd Ed. (2025) (SDPWS 2021, ASCE 7-22): Tables 3.5, 3.13C, 3.18, 3.19 and 4.5.
• WoodWorks, Introduction to Wood: Structural Lateral Framing Design (January 2025 slides): two-story shear wall, slides 56-80.
• AWC Structural Wood Design Examples 2015/2018, E3.1, E3.2, E3.4 (SDPWS 2015), as quoted with inputs, wall figure and results on the free Trimble Tekla Tedds 2026 verification pages (the AWC book itself is not on file).

Two fixes came out of these examples (2026-11-01): the seismic capacity now follows SDPWS 2021 4.1.4 (φD = 0.50 on vn, was 0.80 on vs: the LRFD seismic capacity drops by about 12 %; ASD vn / 2.8 is within 1 plf of the former vs / 2.0), and the SDPWS 2015 aspect ratio rule 2bs/h now applies to wind as well as seismic and to ΣLi of a perforated wall (AWC E3.1, E3.4).

Hand calculations of the remaining provisions, derived step by step in backend/tests/test_verify_wood_shearwall.py. 15/32 in Structural I, 8d at 4 in, OSB: vn = 1,205 plf (SDPWS 2015 vs = 860 plf), Ga = 20 kips/in.