Section A108

DESIGN STRENGTHS

[BS] A108.1 Strength values.

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

148 2019 CALIFORNIA EXISTING BUILDING CODE

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100735044

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

APPENDIX A

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 flooring with board edges offset or perpendicular.	1,500 lbs. per ft. for seismic shear
Horizontal diaphragms	Floors with diagonal sheathing and finished wood flooring.	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:

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 vtL -----

(Equation A1-3)

vmL

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

0.75 vtL -----

The mortar shear strength values, vtL, shall be determined in accordance with Section A106.2.3.5.

When alternate testing is performed in accordance with Section A106.2.3.2, 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.