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Chapter 16 — REFERENCED STANDARDS

Section A108

California Existing Building Code (Title 24, Part 10) · 2022 edition · updated 2026-09-10 · California

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

DESIGN STRENGTHS

[BS] A108.1 Strength values.

  1. Strength values for existing materials are given in Table A108.1(1) and for new materials in Table A108.1(2).
  2. The strength reduction factor, Φ, shall be taken equal to 1.0.
  3. The use of materials not specified herein shall be based on substantiating research data or engineering judgment, as approved by the code official.

APPENDIX A-8 2022 CALIFORNIA EXISTING BUILDING CODE

Copyright © 2022 by, or licensed to, International Code Council, Inc. (ALL RIGHTS RESERVED); licensed to California Building Standards Commission pursuant to License Agreement. No further reproductions is authorized. Any unauthorized reproduction or distribution is a violation of the federal copyright act and the license agreement, and subject to civil and criminal penalties thereunder.

APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS

[BS] TABLE A108.1(1) STRENGTH VALUES FOR EXISTING MATERIALS

EXISTING MATERIALS OR CONFIGURATION OF MATERIALSa STRENGTH VALUES
EXISTING MATERIALS OR CONFIGURATION OF MATERIALSa EXISTING MATERIALS OR CONFIGURATION OF MATERIALSa x 14.594 for N/m
Horizontal diaphragms Roofs with straight sheathing and roofing applied
directly to the sheathing.		 300 lbs. per ft. for seismic shear
Horizontal diaphragms Roofs with diagonal sheathing and roofing applied
directly to the sheathing.		 750 lbs. per ft. for seismic shear
Horizontal diaphragms Floors with straight tongue-and-groove sheathing. 300 lbs. per ft. for seismic shear
Horizontal diaphragms Floors with straight sheathing and finished wood floor-
ing with board edges offset or perpendicular.		 1,500 lbs. per ft. for seismic shear
Horizontal diaphragms Floors with diagonal sheathing and finished wood floor-
ing.		 1,800 lbs. per ft. for seismic shear
Horizontal diaphragms Metal deck welded with minimal welding.c 1,800 lbs. per ft. for seismic shear
Horizontal diaphragms Metal deck welded for seismic resistance.d 3,000 lbs. per ft. for seismic shear
Crosswallsb Plaster on wood or metal lath. 600 lbs. per ft. for seismic shear
Crosswallsb Plaster on gypsum lath. 550 lbs. per ft. for seismic shear
Crosswallsb Gypsum wallboard, unblocked edges. 200 lbs. per ft. for seismic shear
Crosswallsb Gypsum wallboard, blocked edges. 400 lbs. per ft. for seismic shear
Existing footing, wood framing,
structural steel, reinforcing steel		 Plain concrete footings. f′c = 1,500 psi unless otherwise shown by tests
Existing footing, wood framing,
structural steel, reinforcing steel		 Douglas fir wood. Same as D.F. No. 1
Existing footing, wood framing,
structural steel, reinforcing steel		 Reinforcing steel. Fy = 40,000 psi maximum
Existing footing, wood framing,
structural steel, reinforcing steel		 Structural steel. Fy = 33,000 psi maximum

For SI: 1 inch = 25.4 mm, 1 square inch = 645.16 mm 2, 1 pound = 4.4 N, 1 pound per square inch = 6894.75 N/m 2, 1 pound per foot = 14.43 N/m. a. Material must be sound and in good condition. b. Shear values of these materials may be combined, except the total combined value should not exceed 900 pounds per foot. c. Minimum 22-gage steel deck with welds to supports satisfying the standards of the Steel Deck Institute. d. Minimum 22-gage steel deck with 3 /4-inch diameter plug welds at an average spacing not exceeding 8 inches and with sidelap welds appropriate for the deck

span.

[BS] A108.2 Masonry shear strength. The unreinforced masonry shear strength, vmL, shall be determined for each masonry class from one of the following equations:

  1. When testing is performed in accordance with Section A106.2.3.1, the unreinforced masonry shear strength, vm, shall be determined by Equation A1-3.

0.75 0.75 vtLP ------ D

(Equation A1-3)

vmL

= --------------------------------------- - 1.5

0.75 vtLP ------ D An

-

The mortar shear strength values, vtL, shall be determined in accordance with Section A106.2.3.6. 2. When alternate testing is performed in accordance with Section A106.2.3.3, unreinforced masonry shear, vmL, shall be determined by Equation A1-4.

0.75 fsp + P ------ D

(Equation A1-4)

[BS] A108.4 Masonry tension. Unreinforced masonry shall be assumed to have no tensile capacity.

[BS] A108.5 Wall tension anchors. The tension strength of wall anchors shall be the average of the tension test values for anchors having the same wall thickness and framing orientation.

[BS] A108.6 Foundations. For existing foundations, new total dead loads are permitted to be increased over the existing dead load by 25 percent. New total dead load plus live load plus seismic forces may be increased over the existing dead load plus live load by 50 percent. Higher values may be justified only in conjunction with a geotechnical investigation.

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▸Contents — California Existing Building Code (Title 24, Part 10)
California Existing Building Code (Title 24, Part 10)
  1. Chapter 2 — DEFINITIONS
  2. Appendix A — GUIDELINES FOR
  3. Appendix B — SUPPLEMENTARY
  4. Appendix C — GUIDELINES FOR THE WIND
  5. Appendix D — BOARD OF
  6. Chapter 1 — SCOPE AND ADMINISTRATION
  7. Chapter 3 — PROVISIONS FOR ALL COMPLIANCE METHODS
  8. Chapter 4 — REPAIRS
  9. Chapter 5 — PRESCRIPTIVE COMPLIANCE METHOD
  10. Chapter 6 — CLASSIFICATION OF WORK
  11. Chapter 7 — ALTERATIONS—LEVEL 1
  12. Chapter 8 — ALTERATIONS—LEVEL 2
  13. Chapter 9 — ALTERATIONS—LEVEL 3
  14. Chapter 10 — CHANGE OF OCCUPANCY
  15. Chapter 11 — ADDITIONS
  16. Chapter 12 — HISTORIC BUILDINGS
  17. Chapter 13 — PERFORMANCE COMPLIANCE METHODS
  18. Chapter 14 — RELOCATED OR MOVED BUILDINGS
  19. Chapter 15 — CONSTRUCTION SAFEGUARDS
  20. ▸Chapter 16 — REFERENCED STANDARDS
    Overview
    1. Section A100
    2. Section A101
    3. Section A102
    4. Section A103
    5. Section A104
    6. Section A105
    7. Section A106
    8. Section A107
    9. Section A108
    10. Section A109
    11. Section A110
    12. Section A111
    13. Section A112
    14. Section A113
    15. Section A114
    16. Section A201
    17. Section A202
    18. Section A203
    19. Section A204
    20. Section A205
    21. Section A206
    22. Section A207
    23. Section A301
    24. Section A302
    25. Section A303
    26. Section A304
    27. Section A401
    28. Section A403
    29. Section A402
    30. Section A404
    31. Section A405
    32. Section A406
    33. Section A407
    34. Section A501
    35. Section B101
    36. Section B102
    37. Section B103
    38. Section B104
    39. Section C101
    40. Section C102
    41. Section C103
    42. Section C104
    43. Section C201
    44. Section C202
    45. Section C301
    46. Section D101

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