Section 2305 General Design Requirements Forlateral-Force-Resisting Systems
The deflection (Δ) of a blocked wood structural panel diaphragm uniformly fastened throughout with staples is permitted to be calculated by using the following equation. If not uniformly fastened, the constant 0.188 (For SI: 1/1627) in the third term shall be modified accordingly.
(Equation 23-1)
For SI:
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. |
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.
- Increase en values 20 percent for plywood grades other than Structural I.
- Load per fastener = maximum shear per foot divided by the number of fasteners per foot at interior panel edges.
- Decrease en values 50 percent for seasoned lumber (moisture content < 19 percent).
VALUES OF GtFOR 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 Plywood a | 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 (inches) | 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 per inch = 0.1751 N/mm.
- Applies to plywood with five or more layers; for five-ply/three-layer plywood, use values for four ply.
The deflection (Δ) of a blocked wood structural panel shear wall uniformly fastened throughout with staples is permitted to be calculated by the use of the following equation:
(Equation 23-2)
For SI:
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). |