Structures using wood-frame shear walls or wood-frame diaphragms to resist wind, seismic or other lateral loads shall be designed and constructed in accordance with AWC SDPWS and the applicable provisions of Sections 2305, 2306 and 2307.
The deflection of woodframe diaphragms shall be determined in accordance with AWC SDPWS. The deflection (Δ) of a blocked wood structural panel diaphragm uniformly fastened throughout with staples is permitted to be calculated in accordance with Equation 23-1. If not uniformly fastened, the constant 0.188 (For SI: 1/1627) in the third term shall be modified by an approved method.
where:
TABLE 2305.2(1) en VALUES (inches) FOR USE IN CALCULATING DIAPHRAGM AND SHEAR WALL DEFLECTION DUE TO FASTENER SLIP (Structural I)a, c
TABLE 2305.2(2) VALUES OF Gt FOR USE IN CALCULATING DEFLECTION OF WOOD STRUCTURAL PANEL SHEAR WALLS AND DIAPHRAGMS
where:
| A | = | Area of chord cross section, in square inches (mm2). |
| b | = | Diaphragm width, in feet (mm). |
| E | = | Elastic modulus of chords, in pounds per square inch (N/mm2). |
| en | = | Staple deformation, in inches (mm) [see Table 2305.2(1)]. |
| Gt | = | Panel rigidity through the thickness, in pounds per inch (N/mm) of panel width or depth [see Table 2305.2(2)]. |
| L | = | Diaphragm length, in feet (mm). |
| v | = | Maximum shear due to design loads in the direction under consideration, in pounds per linear foot (plf) (N/mm). |
| Δ | = | The calculated deflection, in inches (mm). |
| Σ(ΔcX) | = | Sum of individual chord-splice slip values on both sides of the diaphragm, each multiplied by its distance to the nearest support. |
TABLE 2305.2(1) en VALUES (inches) FOR USE IN CALCULATING DIAPHRAGM AND SHEAR WALL DEFLECTION DUE TO FASTENER SLIP (Structural I)a, c
| LOAD PER FASTENERb (pounds) | FASTENER DESIGNATIONS |
| 14-Ga staple x 2 inches long | |
| 60 | 0.011 |
| 80 | 0.018 |
| 100 | 0.028 |
| 120 | 0.04 |
| 140 | 0.053 |
| 160 | 0.068 |
| For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound = 4.448 N. |
| a. Increase en values 20 percent for plywood grades other than Structural I. |
| b. Load per fastener = maximum shear per foot divided by the number of fasteners per foot at interior panel edges. |
| c. Decrease en values 50 percent for seasoned lumber (moisture content < 19 percent). |
TABLE 2305.2(2) VALUES OF Gt FOR USE IN CALCULATING DEFLECTION OF WOOD STRUCTURAL PANEL SHEAR WALLS AND DIAPHRAGMS
| PANEL TYPE | SPAN RATING | VALUES OF Gt (lb/in. panel depth or width) | |||||||
| Other | Structural I | ||||||||
| 3-ply plywood | 4-ply plywood | 5-ply plywooda | OSB | 3-ply plywood | 4-ply plywood | 5-ply plywooda | OSB | ||
| Sheathing | 24/0 | 25,000 | 32,500 | 37,500 | 77,500 | 32,500 | 42,500 | 41,500 | 77,500 |
| 24/16 | 27,000 | 35,000 | 40,500 | 83,500 | 35,000 | 45,500 | 44,500 | 83,500 | |
| 32/16 | 27,000 | 35,000 | 40,500 | 83,500 | 35,000 | 45,500 | 44,500 | 83,500 | |
| 40/20 | 28,500 | 37,000 | 43,000 | 88,500 | 37,000 | 48,000 | 47,500 | 88,500 | |
| 48/24 | 31,000 | 40,500 | 46,500 | 96,000 | 40,500 | 52,500 | 51,000 | 96,000 | |
| Single Floor | 16 o.c. | 27,000 | 35,000 | 40,500 | 83,500 | 35,000 | 45,500 | 44,500 | 83,500 |
| 20 o.c. | 28,000 | 36,500 | 42,000 | 87,000 | 36,500 | 47,500 | 46,000 | 87,000 | |
| 24 o.c. | 30,000 | 39,000 | 45,000 | 93,000 | 39,000 | 50,500 | 49,500 | 93,000 | |
| 32 o.c. | 36,000 | 47,000 | 54,000 | 110,000 | 47,000 | 61,000 | 59,500 | 110,000 | |
| 48 o.c. | 50,500 | 65,500 | 76,000 | 155,000 | 65,500 | 85,000 | 83,500 | 155,000 | |
| Other | Structural I | ||||||
| Thickness (in.) | A-A, A-C | Marine | All Other Grades | A-A, A-C | Marine | All Other Grades | |
| Sanded Plywood | 1/4 | 24,000 | 31,000 | 24,000 | 31,000 | 31,000 | 31,000 |
| 11/32 | 25,500 | 33,000 | 25,500 | 33,000 | 33,000 | 33,000 | |
| 3/8 | 26,000 | 34,000 | 26,000 | 34,000 | 34,000 | 34,000 | |
| 15/32 | 38,000 | 49,500 | 38,000 | 49,500 | 49,500 | 49,500 | |
| 1/2 | 38,500 | 50,000 | 38,500 | 50,000 | 50,000 | 50,000 | |
| 19/32 | 49,000 | 63,500 | 49,000 | 63,500 | 63,500 | 63,500 | |
| 5/8 | 49,500 | 64,500 | 49,500 | 64,500 | 64,500 | 64,500 | |
| 23/32 | 50,500 | 65,500 | 50,500 | 65,500 | 65,500 | 65,500 | |
| 3/4 | 51,000 | 66,500 | 51,000 | 66,500 | 66,500 | 66,500 | |
| 7/8 | 52,500 | 68,500 | 52,500 | 68,500 | 68,500 | 68,500 | |
| 1 | 73,500 | 95,500 | 73,500 | 95,500 | 95,500 | 95,500 | |
| 11/8 | 75,000 | 97,500 | 75,000 | 97,500 | 97,500 | 97,500 | |
| For SI: 1 inch = 25.4 mm, 1 pound/inch = 0.1751 N/mm. |
| a. Applies to plywood with five or more layers; for five-ply/three-layer plywood, use values for four ply. |
The deflection of wood-frame shear walls shall be determined in accordance with AWC SDPWS. The deflection (Δ) of a blocked wood structural panel shear wall uniformly fastened throughout with staples is permitted to be calculated in accordance with Equation 23-2.
where:
where:
| A | = | Area of boundary element cross section in square inches (mm2) (vertical member at shear wall boundary). |
| b | = | Wall width, in feet (mm). |
| da | = | Vertical elongation of overturning anchorage (including fastener slip, device elongation, anchor rod elongation, etc.) at the design shear load (v). |
| E | = | Elastic modulus of boundary element (vertical member at shear wall boundary), in pounds per square inch (N/mm2). |
| en | = | Staple deformation, in inches (mm) [see Table 2305.2(1)]. |
| Gt | = | Panel rigidity through the thickness, in pounds per inch (N/mm) of panel width or depth [see Table 2305.2(2)]. |
| h | = | Wall height, in feet (mm). |
| v | = | Maximum shear due to design loads at the top of the wall, in pounds per linear foot (N/mm). |
| Δ | = | The calculated deflection, in inches (mm). |