N.Y.C. Admin. Code § BC 2306: Section BC 2306: Allowable Stress Design

2306.1 Allowable stress design.

The design and construction of wood elements in structures using allowable design methods shall be in accordance with the following applicable standards:

American Wood Council.

ANSI/AWC NDS National Design Specification for Wood Construction

ANSI/AWC SDPWS Special Design Provisions for Wind and Seismic

American Society of Agricultural and Biological Engineers.

ASABE EP 484.3 Diaphragm Design of Metal-clad, Wood-frame Rectangular Buildings

ASABE EP 486.2 Shallow Post Foundation Design

ASABE EP 559.1 Design Requirements and Bending Properties for Mechanically Laminated Wood Assemblies

APA – The Engineered Wood Association.

ANSI 117 Standard Specifications for Structural Glued Laminated Timber of Softwood Species

ANSI A190.1 Structural Glued Laminated Timber

Panel Design Specification

Plywood Design Specification Supplement 1 - Design & Fabrication of Plywood Curved Panel

Plywood Design Specification Supplement 2 - Design & Fabrication of Glued Plywood-lumber Beams

Plywood Design Specification Supplement 3 - Design & Fabrication of Plywood Stressed-skin Panels

Plywood Design Specification Supplement 4 - Design & Fabrication of Plywood Sandwich Panels

Plywood Design Specification Supplement 5 - Design & Fabrication of All-plywood Beams

APA T300 Glulam Connection Details

APA S560 Field Notching and Drilling of Glued Laminated Timber Beams

APA S475 Glued Laminated Beam Design Tables

APA X440 Product and Application Guide: Glulam

APA R540 Builders Tips: Proper Storage and Handling of Glulam Beams

Truss Plate Institute, Inc.

TPI 1 National Design Standard for Metal Plate Connected Wood Truss Construction

West Coast Lumber Inspection Bureau

AITC 104 Typical Construction Details

AITC 110 Standard Appearance Grades for Structural Glued Laminated Timber

AITC 113 Standard for Dimensions of Structural Glued Laminated Timber

AITC 119 Standard Specifications for Structural Glued Laminated Timber of Hardwood Species

AITC 200 Inspection Manual

2306.1.1 Joists and rafters.

The design of rafter spans is permitted to be in accordance with the AWC STJR.

2306.1.2 Plank and beam flooring.

The design of plank and beam flooring is permitted to be in accordance with the AWC Wood Construction Data No. 4.

2306.1.3 Treated wood stress adjustments.

The allowable unit stresses for preservative-treated wood shall be adjusted for treatment in accordance with the ANSI/AWC NDS.

The allowable unit stresses for fire-retardant-treated wood, including fastener values, shall be developed from an approved method of investigation that considers the effects of anticipated temperature and humidity to which the fire-retardant-treated wood will be subjected, the type of treatment and the redrying process. Other adjustments are applicable except that the impact load duration shall not apply.

2306.1.4 Lumber decking.

The capacity of lumber decking arranged according to the patterns described in Section 2304.9.2 shall be the lesser of the capacities determined for flexure and deflection according to the formulas in Table 2306.1.4.

Table 2306.1.4 Allowable Loads for Lumber Decking

Pattern

Allowable Area Load

a, b

Flexure

Deflection

Simple span

Two-span continuous

Combination simple- and two-span continuous

Cantilevered pieces intermixed

Controlled random layup

Mechanically laminated decking

2-inch decking

3-inch and 4-inch decking

For SI: 1 inch = 25.4 mm.

a.

s

b

= Allowable total uniform load limited by bending.

s

D

= Allowable total uniform load limited by deflection.

b.

d = Actual decking thickness.

L = Span of decking.

F'

b

= Allowable bending stress adjusted by applicable factors.

E' = Modulus of elasticity adjusted by applicable factors.

2306.2 Wood-frame diaphragms.

Wood-frame diaphragms shall be designed and constructed in accordance with AWC SDPWS. Where panels are fastened to framing members with staples, requirements and limitations of AWC SDPWS shall be met and the allowable shear values set forth in Table 2306.2(1) or 2306.2(2) shall be permitted. The allowable shear values in Tables 2306.2(1) and 2306.2(2) are permitted to be increased 40 percent for wind design.

Table 2306.2(1) Allowable Shear Values (Pounds per Foot) for Wood Structural Panel Diaphragms Utilizing Staples with Framing of Douglas Fir-Larch, or Southern Pine

a

for Wind or Seismic Loading

f

Panel Grade

Staple Length and Gaged

Minimum Fastener Penetration in Framing (inches)

Minimum Nominal Panel Thickness (inch)

Minimum Nominal Width of Framing Members at Adjoining Panel Edges and Boundaries

e

(inches)

Blocked Diaphragms

Unblocked Diaphragms

Fastener spacing (inches) at diaphragm boundaries (all cases) at continuous panel edges parallel to load (Cases 3,4), and at all panel edges (Cases 5,6)

b

Fasteners spaced 6 max. at supported edges

b

6

4

2 1/2

c

2

c

Case 1 (No unblocked edges or continuous joints parallel to load)

All other configurations (Cases 2, 3, 4, 5 and 6)

Fastener spacing (inches) at other panel edges (Cases 1, 2, 3 and 4)

b

6

6

4

3

Structural I grades

1 1/2 16 Gage

1

3/8

2

175

235

350

400

155

115

3

200

265

395

450

175

130

15/32

2

175

235

350

400

155

120

3

200

265

395

450

175

130

Sheathing, single floor and other grades covered in DOC PS 1 and PS 2

1 1/2 16 Gage

1

3/8

2

160

210

315

360

140

105

3

180

235

355

400

160

120

7/16

2

165

225

335

380

150

110

3

190

250

375

435

165

125

15/32

2

160

210

315

360

140

105

3

180

235

355

405

160

120

19/32

2

175

235

350

400

155

115

3

200

265

395

450

175

130

For SI: 1 inch = 25.4 mm, 1 pound per foot = 14.5939 N/m.

a. For framing of other species: (1) Find specific gravity for species of lumber in ANSI/AWC NDS. (2) For staples, find shear value from table above for Structural I panels (regardless of actual grade) and multiply value by 0.82 for species with specific gravity of 0.42 or greater, or 0.65 for all other species.

b. Space fasteners maximum 12 inches on center along intermediate framing members (6 inches on center where supports are spaced 48 inches on center).

c. Framing at adjoining panel edges shall be 3 inches nominal or wider.

d. Staples shall have a minimum crown width of 7/16 inch and shall be installed with their crowns parallel to the long dimension of the framing members.

e. The minimum nominal width of framing members not located at boundaries or adjoining panel edges shall be 2 inches.

f. For shear loads of normal or permanent load duration as defined by the ANSI/AWC NDS, the values in the table above shall be multiplied by 0.63 or 0.56, respectively.

Table 2306.2(2) Allowable Shear Values (pounds per foot) for Wood Structural Panel Blocked Diaphragms Utilizing Multiple Rows of Staples (High-Load Diaphragms) with Framing of Douglas Fir-Larch or Southern Pine

a

for Wind or Seismic Loading

b, g, h

Panel Grade

Staple Gage

f

Minimum Fastener Penetration in Framing (inches)

Minimum Nominal Panel Thickness (inch)

Minimum Nominal Width of Framing Members at Adjoining Panel Edges and Boundaries

e

Lines of Fasteners

Blocked Diaphragms

Cases 1 and 2

d

Fastener Spacing Per Line at Boundaries (inches)

4

2 1/2

2

Fastener Spacing Per Line at Other Panel Edges (inches)

6

4

4

3

3

2

Structural I grades

14 Gage Staples

2

15/32

3

2

600

600

860

960

1,060

1,200

4

3

860

900

1,160

1,295

1,295

1,400

19/32

3

2

600

600

875

960

1,075

1,200

4

3

875

900

1,175

1,440

1,475

1,795

Sheathing, single floor and other grades covered in DOC PS 1 and PS 2

14 Gage Staples

2

15/32

3

2

540

540

735

865

915

1,080

4

3

735

810

1,005

1,105

1,105

1,195

19/32

3

2

600

600

865

960

1,065

1,200

4

3

865

900

1,130

1,430

1,370

1,485

23/32

4

3

865

900

1,130

1,490

1,430

1,545

For SI: 1 inch = 25.4 mm, 1 pound per foot = 14.5939 N/m.

a. For framing of other species: (1) Find specific gravity for species of framing lumber in ANSI/AWC NDS. (2) For staples, find shear value from table above for Structural I panels (regardless of actual grade) and multiply value by 0.82 for species with specific gravity of 0.42 or greater, or 0.65 for all other species.

b. Fastening along intermediate framing members: Space fasteners not greater than 12 inches on center, except 6 inches on center for spans greater than 32 inches.

c. Panels conforming to PS 1 or PS 2.

d. This table gives shear values for Cases 1 and 2 as shown in Table 2306.2(1). The values shown are applicable to Cases 3, 4, 5 and 6 as shown in Table 2306.2(1), providing fasteners at all continuous panel edges are spaced in accordance with the boundary fastener spacing.

e. The minimum nominal depth of framing members shall be 3 inches nominal. The minimum nominal width of framing members not located at boundaries or adjoining panel edges shall be 2 inches.

f. Staples shall have a minimum crown width of 7/16 inch, and shall be installed with their crowns parallel to the long dimension of the framing members.

g. High-load diaphragms shall be subject to special inspection in accordance with Section 1705.5.1.

h. For shear loads of normal or permanent load duration as defined by the ANSI/AWC NDS, the values in the table above shall be multiplied by 0.63 or 0.56, respectively.

2306.2.1 Gypsum board diaphragm ceilings.

Gypsum board diaphragm ceilings shall be in accordance with Section 2508.5.

2306.3 Wood-frame shear walls.

Wood-frame shear walls shall be designed and constructed in accordance with AWC SDPWS. Where panels are fastened to framing members with staples, requirements and limitations of AWC SDPWS shall be met and the allowable shear values set forth in Table 2306.3(1), 2306.3(2) or 2306.3(3) shall be permitted. The allowable shear values in Tables 2306.3(1) and 2306.3(2) are permitted to be increased 40 percent for wind design. Panels complying with ANSI/APA PRP-210 shall be permitted to use design values for Plywood Siding in the AWC SDPWS.

Table 2306.3(1) Allowable Shear Values (pounds per foot) for Wood Structural Panel Shear Walls Utilizing Staples with Framing of Douglas Fir-Larch or Southern Pine

a

for Wind or Seismic Loading

b, f, g, i

Panel Grade

Minimum Nominal Panel Thickness (inch)

Minimum Fastener Penetration in Framing (inches)

Panels Applied Direct to Framing

Panels Applied over 1/2" or 5/8" Gypsum Sheathing

Staple length and gage (inches)

h

Fastener spacing at panel edges (inches)

Staple length and gage (inches)

h

Fastener spacing at panel edges (inches)

6

4

3

2

d

6

4

3

2

d

Structural I grades

3/8

1

1 1/2 16 Gage

155

235

315

400

2 16 Gage

155

235

310

400

7/16

170

260

345

440

155

235

310

400

15/32

185

280

375

475

155

235

300

400

Sheathing, plywood siding

e

except Group 5 Species

5/16

c

or 1/4

c

1

1 1/2 16 Gage

145

220

295

375

2 16 Gage

110

165

220

285

3/8

140

210

280

360

140

210

280

360

7/16

155

230

310

395

140

210

280

360

15/32

170

255

335

430

140

210

280

360

19/32

1 3/4 16 Gage

185

280

375

475

–

–

–

–

–

For SI: 1 inch = 25.4 mm, 1 pound per foot = 14.5939 N/m.

a. For framing of other species: (1) Find specific gravity for species of lumber in ANSI/AWC NDS. (2) For staples, find shear value from table above for Structural I panels (regardless of actual grade) and multiply value by 0.82 for species with specific gravity of 0.42 or greater, or 0.65 for all other species.

b. Panel edges backed with 2-inch nominal or wider framing. Install panels either horizontally or vertically. Space fasteners maximum 6 inches on center along intermediate framing members for 3/8-inch and 7/16-inch panels installed on studs spaced 24 inches on center. For other conditions and panel thickness, space fasteners maximum 12 inches on center on intermediate supports.

c. 3/8-inch panel thickness or siding with a span rating of 16 inches on center is the minimum recommended where applied directly to framing as exterior siding. For grooved panel siding, the nominal panel thickness is the thickness of the panel measured at the point of fastening.

d. Framing at adjoining panel edges shall be 3 inches nominal or wider.

e. Values apply to all-veneer plywood. Thickness at point of fastening on panel edges governs shear values.

f. Where panels are applied on both faces of a wall and fastener spacing is less than 6 inches on center on either side, panel joints shall be offset to fall on different framing members, or framing shall be 3 inches nominal or thicker at adjoining panel edges.

g. In Seismic Design Category D where shear design values exceed 350 pounds per linear foot, all framing members receiving edge fastening from abutting panels shall be not less than a single 3-inch nominal member, or two 2-inch nominal members fastened together in accordance with Section 2306.1 to transfer the design shear value between framing members. Wood structural panel joint and sill plate nailing shall be staggered at all panel edges. See AWC SDPWS for sill plate size and anchorage requirements.

h. Staples shall have a minimum crown width of 7/16-inch and shall be installed with their crowns parallel to the long dimension of the framing members.

i. For shear loads of normal or permanent load duration as defined by the ANSI/AWC NDS, the values in the table above shall be multiplied by 0.63 or 0.56, respectively.

Table 2306.3(2) Allowable Shear Values (Plf) for Wind or Seismic Loading on Shear Walls of Fiberboard Sheathing Board Construction Utilizing Staples for Type V Construction Only

a, b, c, d, e

Thickness and Grade (inches)

Staple Gage and Dimensions

Allowable Shear Value (pounds per linear foot) Staple Spacing at Panel Edges (inches)

a

4

3

2

1/2" or 25/32" Structural

No. 16 gage galvanized staple, 7/16 inch crown 1 3/4 inch long

150

200

225

No. 16 gage galvanized staple, 1 inch crown 1 3/4 inch long

220

290

325

For SI: 1 inch = 25.4 mm, 1 pound per linear foot = 14.5939 N/m.

a. Fiberboard sheathing shall not be used to brace concrete or masonry walls.

b. Panel edges shall be backed with 2-inch or wider framing of Douglas Fir-larch or Southern Pine. For framing of other species: (1) Find specific gravity for species of framing lumber in ANSI/AWC NDS. (2) For staples, multiply the shear value from the table above by 0.82 for species with specific gravity of 0.42 or greater, or 0.65 for all other species.

c. Values shown are for fiberboard sheathing on one side only with long panel dimension either parallel or perpendicular to studs.

d. Fastener shall be spaced 6 inches on center along intermediate framing members.

e. Values are not permitted in Seismic Design Category D.

Table 2306.3(3) Allowable Shear Values for Wind or Seismic Forces for Shear Walls of Lath and Plaster or Gypsum Board Wood Framed Wall Assemblies Utilizing Staples

Type of Material

Thickness of Material

Wall Construction

Staple Spacing

b

Maximum (inches)

Shear Value

a, c

(plf)

Minimum Staple Size

f, g

1. Expanded metal or woven wire lath and portland cement plaster

7/8"

Unblocked

6

180

No. 16 gage galv. staple, 7/8" legs

2. Gypsum lath, plain or perforated

3/8" lath and 1/2" plaster

Unblocked

5

100

No. 16 gage galv. staple, 1 1/8" long

3. Gypsum sheeting

1/2" × 2' × 8'

Unblocked

4

75

No. 16 gage galv. staple, 1 3/4" long

1/2" × 4'

Blocked

d

4

175

Unblocked

7

100

4. Gypsum board, gypsum veneer base or water-resistant gypsum backing board

1/2"

Unblocked

d

7

75

No. 16 gage galv. staple, 1 1/2" long

Unblocked

d

4

110

Unblocked

7

100

Unblocked

4

125

Blocked

e

7

125

Blocked

e

4

150

5/8"

Unblocked

d

7

115

No. 16 gage galv. staple, 1 1/2" legs, 1 5/8" long

4

145

Blocked

e

7

145

4

175

Blocked

e

Two-ply

Base ply: 9 Face ply: 7

250

No. 16 gage galv. staple, 1 5/8" long No. 15 gage galv. staple, 2 1/4" long

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per foot = 14.5939 N/m.

a. These shear walls shall not be used to resist loads imposed by masonry or concrete walls (see AWC SDPWS). Values shown are for short-term loading due to wind or seismic loading. Walls resisting seismic loads shall be subject to the limitations in Section 12.2.1 of ASCE 7. Values shown shall be reduced 25 percent for normal loading.

b. Applies to fastening at studs, top and bottom plates and blocking.

c. Except as noted, shear values are based on a maximum framing spacing of 16 inches on center.

d. Maximum framing spacing of 24 inches on center.

\e. All edges are blocked, and edge fastening is provided at all supports and all panel edges.

f. Staples shall have a minimum crown width of 7/16 inch, measured outside the legs, and shall be installed with their crowns parallel to the long dimension of the framing members.

g. Staples for the attachment of gypsum lath and woven-wire lath shall have a minimum crown width of 3/4 inch, measured outside the legs.