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Chapter 23 — WOOD

Section 2305 — GENERAL DESIGN REQUIREMENTS FOR LATERAL FORCE-RESISTING SYSTEMS

2025 California Building Code (Title 24, Part 2) · 2025 edition · updated 2026-07-29 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

2305.1 General.

Structures using wood shear walls or wood diaphragms to resist wind or seismic loads shall be designed and constructed in accordance with AWC SDPWS and the applicable provisions of Sections 2305, 2306 and 2307.

2305.1.1 Openings in shear panels. Openings in shear panels that materially affect their strength shall be detailed on the plans and shall have their edges adequately reinforced to transfer all shearing stresses.

2305.1.2 Permanent load duration. Permanent loads are associated with permanent load duration in accordance with the ANSI/AWC NDS. For wood shear walls and wood diaphragms designed to resist lateral loads of permanent load duration only and that are not in combination with wind or seismic lateral loads, the design unit shear capacities shall be taken as the AWC SDPWS nominal unit shear capacities, multiplied by 0.2 for use with allowable stress design in Section 2306 and 0.3 for use with load and resistance factor design in Section 2307.

2305.1.3 Additional requirements. [DSA-SS, DSA-SS/CC, OSHPD 1, 1R, 2, 4 & 5] See Section 2301.1.5 for modifications to AWC SDPWS.

2305.2 Diaphragm deflection.

The deflection of wood-frame diaphragms shall be determined in accordance with AWC SDPWS. The deflection (Δ dia ) 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. Equation 23-1 Δ dia = 5 vL [3] /8 EAW + vL /4 Gt + 0.188 Le n + Σ( x Δ c )/2 W For SI: Δ dia = 0.052 vL [3] / EAW + vL /4 Gt + Le n /1627 + Σ( x Δ c )/2 W

where:

A = Area of chord cross section, in square inches (mm [2] ). E = Modulus of elasticity of diaphragm chords, in pounds per square inch (N/mm [2] ).

e n = Staple slip, 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 (dimension perpendicular to the direction of the applied load), in feet (mm).

v = Induced unit shear in pounds per linear foot (plf) (N/mm).

W = Diaphragm width [in the direction of applied force, in feet (mm)].

x = Distance from chord splice to nearest support, in feet (mm).

Δ c = Diaphragm chord splice slip at the induced unit shear, in inches (mm). Δ dia = Maximum mid-span diaphragm deflection determined by elastic analysis, in inches (mm).

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

WOOD

TABLE 2305.2(1)—e VALUES (inches) FOR USE IN CALCULATING
n
DIAPHRAGM AND SHEAR WALL DEFLECTION DUE TO FASTENER SLIP (Structural I)a, c

LOAD PER FASTENERb (pounds) FASTENER DESIGNATIONS
LOAD PER FASTENERb (pounds) 14-Ga staple × 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 OFGt (lb/in. panel depth or width) VALUES OFGt (lb/in. panel depth or width) VALUES OFGt (lb/in. panel depth or width) VALUES OFGt (lb/in. panel depth or width) VALUES OFGt (lb/in. panel depth or width) VALUES OFGt (lb/in. panel depth or width) VALUES OFGt (lb/in. panel depth or width) VALUES OFGt (lb/in. panel depth or width)
PANEL
TYPE		 SPAN
RATING		 Structural Sheathing Structural Sheathing Structural Sheathing Structural Sheathing Structural I Structural I Structural I Structural I
PANEL
TYPE		 SPAN
RATING		 Plywood Plywood Plywood OSB Plywood Plywood Plywood OSB
PANEL
TYPE		 SPAN
RATING		 3-ply 4-ply 5-plya 5-plya 3-ply 4-ply 5-plya 5-plya
Sheathing 24/0 25,000 32,500 37,500 77,500 32,500 42,500 41,500 77,500
Sheathing 24/16 27,000 35,000 40,500 83,500 35,000 45,500 44,500 83,500
Sheathing 32/16 27,000 35,000 40,500 83,500 35,000 45,500 44,500 83,500
Sheathing 40/20 28,500 37,000 43,000 88,500 37,000 48,000 47,500 88,500
Sheathing 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
Single
Floor		 20 o.c. 28,000 36,500 42,000 87,000 36,500 47,500 46,000 87,000
Single
Floor		 24 o.c. 30,000 39,000 45,000 93,000 39,000 50,500 49,500 93,000
Single
Floor		 32 o.c. 36,000 47,000 54,000 110,000 47,000 61,000 59,500 110,000
Single
Floor		 48 o.c. 50,500 65,500 76,000 155,000 65,500 85,000 83,500 155,000
Structural Sheathing 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
Sanded
Plywood		 11/32 25,500 33,000 25,500 33,000 33,000 33,000
Sanded
Plywood		 3/8 26,000 34,000 26,000 34,000 34,000 34,000
Sanded
Plywood		 15/32 38,000 49,500 38,000 49,500 49,500 49,500
Sanded
Plywood		 1/2 38,500 50,000 38,500 50,000 50,000 50,000
Sanded
Plywood		 19/32 49,000 63,500 49,000 63,500 63,500 63,500
Sanded
Plywood		 5/8 49,500 64,500 49,500 64,500 64,500 64,500
Sanded
Plywood—
continued		 23/32 50,500 65,500 50,500 65,500 65,500 65,500
Sanded
Plywood—
continued		 3/4 51,000 66,500 51,000 66,500 66,500 66,500
Sanded
Plywood—
continued		 7/8 52,500 68,500 52,500 68,500 68,500 68,500
Sanded
Plywood—
continued		 1 73,500 95,500 73,500 95,500 95,500 95,500
Sanded
Plywood—
continued		 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. 5-ply applies to plywood with five or more layers. For 5-ply plywood with three layers, use values for 4-ply panels.

23-26 2025 CALIFORNIA BUILDING CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

WOOD

2305.3 Shear wall deflection.

The deflection of wood-frame shear walls shall be determined in accordance with AWC SDPWS. The deflection (Δ sw ) of a blocked wood structural panel shear wall uniformly fastened throughout with staples is permitted to be calculated in accordance with Equation 23-2. Equation 23-2 Δ sw = 8 vh [3] / EAb + vh /4 Gt + 0.75 he n + d a h / b

For SI:

Δ sw = vh 3 3EAb⁄ + vh Gt⁄ + -----------407.6 he n - + d a h b⁄

where:

A = Area of end-post cross section in square inches (mm [2] ).

b = Shear wall length, in feet (mm).

d a = Total vertical elongation of wall anchorage system (such as fastener slip, device elongation, rod elongation) in inches (mm), at the induced unit shear in the shear wall ( v ).

E = Modulus of elasticity of end posts, in pounds per square inch (N/mm [2] ).

e n = Staple slip, 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 = Shear wall height, in feet (mm).

v = Induced unit shear, in pounds per linear foot (N/mm).

Δ sw = Maximum shear wall deflection determined by elastic analysis, in inches (mm).

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▸ Contents — 2025 California Building Code (Title 24, Part 2)
2025 California Building Code (Title 24, Part 2)
  1. Chapter 1 — ADMINISTRATION
  2. Chapter 2 — DEFINITIONS
  3. Chapter 3 — OCCUPANCY CLASSIFICATION AND USE
  4. Chapter 4 — SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY A…
  5. Chapter 5 — GENERAL BUILDING HEIGHTS AND AREAS
  6. Chapter 6 — TYPES OF CONSTRUCTION
  7. Chapter 7 — FIRE AND SMOKE PROTECTION FEATURES
  8. Chapter 7A — MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR W…
  9. Chapter 8 — INTERIOR FINISHES
  10. Chapter 9 — FIRE PROTECTION AND LIFE SAFETY SYSTEMS
  11. Chapter 10 — MEANS OF EGRESS
  12. Chapter 11 — RESERVED
  13. Chapter 11A — HOUSING ACCESSIBILITY
  14. Chapter 11B — ACCESSIBILITY TO PUBLIC BUILDINGS, PUBLIC ACCOMM…
  15. Chapter 12 — INTERIOR ENVIRONMENT
  16. Chapter 13 — ENERGY EFFICIENCY
  17. Chapter 14 — EXTERIOR WALLS
  18. Chapter 15 — ROOF ASSEMBLIES AND ROOFTOP STRUCTURES
  19. Chapter 16 — STRUCTURAL DESIGN
  20. Chapter 16A — STRUCTURAL DESIGN
  21. Chapter 17 — SPECIAL INSPECTIONS AND TESTS
  22. Chapter 17A — SPECIAL INSPECTIONS AND TESTS
  23. Chapter 18 — SOILS AND FOUNDATIONS
  24. Chapter 18A — SOILS AND FOUNDATIONS
  25. Chapter 19 — CONCRETE
  26. Chapter 19A — CONCRETE
  27. Chapter 20 — ALUMINUM
  28. Chapter 21 — MASONRY
  29. Chapter 21A — MASONRY
  30. Chapter 22 — STEEL
  31. Chapter 22A — STEEL
  32. ▸ Chapter 23 — WOOD
    Overview
    1. Section 2301 — GENERAL
    2. Section 2302 — DESIGN REQUIREMENTS
    3. Section 2303 — MINIMUM STANDARDS AND QUALITY
    4. Section 2304 — GENERAL CONSTRUCTION REQUIREMENTS
    5. Section 2305 — GENERAL DESIGN REQUIREMENTS FOR LATERAL FORCE-R…
    6. Section 2306 — ALLOWABLE STRESS DESIGN
    7. Section 2307 — LOAD AND RESISTANCE FACTOR DESIGN
    8. Section 2308 — CONVENTIONAL LIGHT-FRAME CONSTRUCTION
    9. Section 2309 — WOOD FRAME CONSTRUCTION MANUAL
  33. Chapter 24 — GLASS AND GLAZING
  34. Chapter 25 — GYPSUM PANEL PRODUCTS AND PLASTER
  35. Chapter 26 — PLASTIC
  36. Chapter 27 — ELECTRICAL
  37. Chapter 28 — MECHANICAL SYSTEMS
  38. Chapter 29 — PLUMBING SYSTEMS
  39. Chapter 30 — ELEVATORS AND CONVEYING SYSTEMS
  40. Chapter 31 — SPECIAL CONSTRUCTION
  41. Chapter 31A — SYSTEMS FOR WINDOW CLEANING OR EXTERIOR BUILDING…
  42. Chapter 31B — PUBLIC POOLS
  43. Chapter 31C — RADIATION
  44. Chapter 31D — FOOD ESTABLISHMENTS
  45. Chapter 31F — MARINE OIL TERMINALS
  46. Chapter 32 — ENCROACHMENTS INTO THE PUBLIC RIGHT-OF-WAY
  47. Chapter 33 — SAFEGUARDS DURING CONSTRUCTION
  48. Chapter 34 — RESERVED
  49. Chapter 35 — REFERENCED STANDARDS
  50. Appendix A — EMPLOYEE QUALIFICATIONS
  51. Appendix B — BOARD OF APPEALS
  52. Appendix C — GROUP U—AGRICULTURAL BUILDINGS
  53. Appendix D — FIRE DISTRICTS
  54. Appendix E — RESERVED
  55. Appendix F — RODENTPROOFING
  56. Appendix G — FLOOD-RESISTANT CONSTRUCTION
  57. Appendix H — SIGNS
  58. Appendix I — PATIO COVERS
  59. Appendix J — GRADING
  60. Appendix K — GROUP R-3 AND GROUP R-3.1 OCCUPANCIES PROTECTED B…
  61. Appendix L — EARTHQUAKE RECORDING INSTRUMENTATION
  62. Appendix M — TSUNAMI-GENERATED FLOOD HAZARDS
  63. Appendix N — REPLICABLE BUILDINGS
  64. Appendix O — PERFORMANCE-BASED APPLICATION
  65. Appendix P — SLEEPING LOFTS
  66. Appendix Q — EMERGENCY HOUSING

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