Shear Wall Calculator
Check a wood shear wall: enter the sheathed panels along a wall line, the sheathing and its nailing, and the wind and earthquake load on the line, and see whether the panels hold it. Pro adds the hold-down forces, the anchor bolt spacing and a PDF report.
The wall line works with 7/16 in Rated sheathing, 8d nails on one face and 6 in edge nailing, using 71% of its capacity (limited by wind).
The wall line's full-height sheathed panels, the wind load along its top, and the hold-downs at each panel's ends.
Load on the wall line
| Wind2,880 lb (0.6 × 4,800 lb) on 4,032 lb | 71% |
| Earthquake808 lb (0.7 × 1,154 lb) on 2,880 lb | 28% |
7/16 in Rated sheathing, 8d nails on one face
| 6 in edge nailing | 71% |
| 4 in edge nailing | 49% |
| 3 in edge nailing | 38% |
| 2 in edge nailing | 29% |
Panels
| Panel | Width | h/b | Factor | Wind plf | Quake plf | Takes plf |
|---|---|---|---|---|---|---|
| Panel 1 | 4′ | 2.00 | 1.00 | 336 | 240 | 240 |
| Panel 2 | 8′ | 1.00 | 1.00 | 336 | 240 | 240 |
Allowable unit shear in pounds per foot, after the framing factor (1.00) and, for panels more than twice as tall as wide, the aspect ratio factor. Each panel takes the line's load in proportion to its capacity.
Hold-downs and anchor bolts Pro
The uplift each hold-down has to resist and the push down on the end studs, panel by panel, and the spacing of the anchor bolts along the sill, with a PDF report of the whole wall line.
Wind 20 psf on 20′ by 12′ of building face; earthquake SDS 0.5 × 15,000 lb / R 6.5, both at strength level. Rated sheathing panels blocked at every edge, nailed directly to the framing. Shear wall deflection and the diaphragm above aren't checked.
Allowable unit shear for wood shear walls
Pounds per foot of wall, wind / earthquake, at allowable stress, for panels blocked at every edge and nailed directly to Douglas Fir-Larch or Southern Pine framing with common or galvanized box nails, one face sheathed. From IBC Table 2306.3; wind takes 1.4 times the earthquake value.
| Sheathing | 6 in nailing | 4 in nailing | 3 in nailing | 2 in nailing |
|---|---|---|---|---|
| 3/8 in Structural I, 8d nails | 322 / 230 | 504 / 360 | 644 / 460 | 854 / 610 |
| 7/16 in Structural I, 8d nails | 357 / 255 | 553 / 395 | 707 / 505 | 938 / 670 |
| 15/32 in Structural I, 8d nails | 392 / 280 | 602 / 430 | 770 / 550 | 1022 / 730 |
| 15/32 in Structural I, 10d nails | 476 / 340 | 714 / 510 | 931 / 665 | 1218 / 870 |
| 5/16 in Rated sheathing, 6d nails | 252 / 180 | 378 / 270 | 490 / 350 | 630 / 450 |
| 3/8 in Rated sheathing, 6d nails | 280 / 200 | 420 / 300 | 546 / 390 | 714 / 510 |
| 3/8 in Rated sheathing, 8d nails | 308 / 220 | 448 / 320 | 574 / 410 | 742 / 530 |
| 7/16 in Rated sheathing, 8d nails | 336 / 240 | 490 / 350 | 630 / 450 | 819 / 585 |
| 15/32 in Rated sheathing, 8d nails | 364 / 260 | 532 / 380 | 686 / 490 | 896 / 640 |
| 15/32 in Rated sheathing, 10d nails | 434 / 310 | 644 / 460 | 840 / 600 | 1078 / 770 |
| 19/32 in Rated sheathing, 10d nails | 476 / 340 | 714 / 510 | 931 / 665 | 1218 / 870 |
Hem-Fir framing takes 0.93 of these, Spruce-Pine-Fir 0.92.
How the calculator checks a shear wall
A shear wall is a stretch of wall sheathed with plywood or oriented strand board (OSB) that keeps the building from racking sideways. The calculator follows the Special Design Provisions for Wind and Seismic (SDPWS) 2021 with allowable stress design (ASD):
- Loads: the wind on the building face the wall line holds, at strength level, times 0.6; and the earthquake load, ρ SDS W / R with R = 6.5 for light wood framing sheathed with wood structural panels, times 0.7 (ASCE 7).
- Panels: only full-height stretches of sheathing count. Each panel's allowable unit shear comes from the table above, adjusted for lighter framing species, and for panels taller than twice their width, times 1.25 − 0.125 h/b. Panels more than 3.5 times as tall as wide don't count. Sheathing on both faces doubles it.
- Sharing: the panels share the wall line's load in proportion to their capacity, and the line works when the load is no more than the sum of their capacities.
- Hold-downs (Pro): each panel's shear times the wall height, over the distance between its hold-downs (3 in in from each end), less 0.6 times the dead load on the panel for wind, or 0.6 − 0.14 SDS for earthquakes. The wall's own weight is taken as 10 psf.
- Anchor bolts (Pro): each bolt's capacity along the sill from the National Design Specification (NDS) yield equations for a 2x sill bolted to concrete, the basis of NDS Table 12E, with the load duration factor 1.6. They're spaced to carry the panels' unit shear, at most 6 ft apart.
Not checked: the shear wall's deflection and story drift, the floor or roof diaphragm that brings the load to the wall, the collectors and straps around openings, and the hold-down hardware itself.
Shear wall questions
What counts as a shear wall panel?
A stretch of wall sheathed from the bottom plate to the top plate with no openings, blocked at every panel edge. A wall with a window has a panel each side of the window, not one long one. Narrow panels beside openings count for less, and those more than 3.5 times as tall as wide (under 2′ 3″ in an 8 ft wall) don't count at all.
Which wind pressure do I enter?
The whole-building (main wind force resisting system) pressure on the wall the wind hits plus the one it leaves, from the wind load calculator, at strength level. ASCE 7 asks for at least 16 psf on walls. The wind load calculator links here with it filled in.
Where do I find SDS?
The ASCE Hazard Tool gives it for an address and soil class. Much of the central and eastern US is under 0.3; coastal California runs over 1.0. Enter 0 to check wind alone.
Does closer nailing always help?
Yes, up to a point: 4, 3 and 2 in edge nailing carry about 1.5, 2 and 2.6 times as much as 6 in. Nailing at 2 in needs 3x framing where panels meet so the wood doesn't split.
What about the studs in the wall?
The stud wall calculator checks the studs for the load from above and the wind on the wall's face. The end studs of each shear wall panel also take the hold-down's push and pull.