Structural Fiberboard

Shearwalls

SDPWS / ASCE 7

Major References

SDPWS 4.3.7.4 and Table 4.3A

Wall Construction

(for more details, see table fable for Wall Construction )

Reference

SDWPS 4.3.7.4.

Surface

Either or both

Either or both

Orientation

Vertical

Vertical

Blocking

Blocked

Blocked

Max Stud Spacing

16”

16"

Stud Thickness

2” nominal

2” nominal

Sheathing and Fasteners

Sheathing thickness

½”, 25/32”

½”, 25/32”

Fastener spacing (for more details, see Fastener spacing table)

Edge spacing

2”, 3”, 4”

2”, 3”, 4”

Interior Spacing

2”-6”

6” max

Fastener types and sizes ( for more details, see Table for Fastener type and lengths

Common nail (not box)

Not included

not included

11 ga galv roofing nail

1½”, 1¾

1½”, 1¾ “

ASD Shear Capacity

Reference

Tabulated values divided by ASD reduction factor

SDPWS Table 4.3A , 4.1.4, unfactored

4"

3"

2"

4"

3"

2"

For wind design

237.5

322.5

365

475

645

730

For seismic design

169.6

230.4

260.7

Capacities given are for 4", 3", 2" panel edge nail spacing. Same capacity for both sheathing thicknesses.

Shear Capacity Adjustments and Notes

Reference

Notes under Sheathing Materials Table

SDPWS Table 4.3A Notes, 4.3.5 , 4.1.4

Specific Gravity (G) factor

1 - ( 0.5 - G)

1 - ( 0.5 - G)

Note for G

Note 1

Note 3:

ASD Reduction Factor

Incorporated into design values

SDPWS 4.1.4

Wind design

2.0

2.0

Seismic design

2.8

2.8

Note for ASD Factor

No note

Note 1 referring to 4.1.4

Aspect Ratio Factor

See section below this one

See below section

Perforated Wall Factor

Gypsum only allowed in combination with wood structural panels on perforated walls; refer to Wood Structural Panel Provisions

Aspect Ratios and Capacity Adjustment

Aspect ratio - h/b b = segment length, h =height. Applies to wall segments or FTAO piers.

( For more details see Aspect Ratio Limits and Factors )

Maximum aspect ratio

Aspect ratio shown in Elevation view for each segment.

SDPWS 4.3.3, Table 4.3.3

Adjusted

3.5:1

3.5:1

Unadjusted

1:1

1:1

Shear Capacity Adjustment

If not 1.0, shown in Elevation view. Also shown in Shear Design Results.

Segmented or FTAO walls*

4.3.3.2, 4.3.5.5.1 Exception 2

Capacity-based force distribution

0.1 + 0.9 b/ h

0.1 + 0.9 b/ h

Deflection-based force distribution

1.09 - 0.09 h/b

1.09 - 0.09 h/b

Perforated walls**

SDPWS 4.3.5.6, 4.3.3.4, Eqn. 4.3-5

All types of force distribution

Sb_i /Sb; b_i = 2b/h when h/b > 2

Sb_i /Sb; b_i = 2b/h when h/b > 2

*Applies to shear wall segments with aspect ratio between 1.0 and 3.5.

**Fiberboard is only allowed in combination with wood structural panels on perforated walls. On such walls, the perforated wall factor is applied to the fiberboard sheathing capacity rather than the Aspect ratio for fiberboard, as per 4.3.3.4.

Combination of Sheathing Capacities

For more details, refer to Combination of Sheathing Capacities,

Reference

SDPWS 4.3.5.4, , 4.3.5.4.2 Exception

Identical materials on both sides

Add capacities

Add capacities

With fiberboard with different specs on other side

V_wc=K_min G_ac

V_sc =K_min G_ac

With non-fiberboard on other side for seismic design

Twice weakest or strongest

Twice weakest or strongest

With gypsum wallboard or gypsum sheathing board on other side for wind design

Add capacities

Add capacities*

With lumber siding, wood structural panels, or lath/plaster on other side for wind desigm

Twice weakest or strongest

Twice weakest or strongest

Twice weakest or strongest: v_n(c) = max ( 2 x min ( v_n(1) ,v_n(2)) , max( v_n(1),v_n(2) ) )

Combination of Apparent Stiffness Ga

For more details, refer to Combination of Sheathing Stiffness

Reference

SDPWS 4.3.5.4

Identical materials on both sides

Add stiffnesses

Add stiffnesses

With fiberboard with different specs on other side

Add stiffnesses

Add stiffnesses

With non-fiberboard on other side

Twice side with weakest capacity or side with strongest cap.

Twice side with weakest capacity or side with strongest

Twice weakest capacity or side with strongest cap: G_a(c) = max (2 x G_a (min ( v_n(1) ,v_n(2))) , G_a (max( v_n(1),v_n(2) )))

Permissible Force Distribution Method

Refer to Shear Force Distribution Methods for more a description of these methods and how they are selected.

Reference

SDPWS 4.3.5.5.1, inc. Exception 2,

Deflection-based distribution

Allowed

Allowed

Capacity-based distribution

Aspect ratio adjustment applied to narrow segments, see above

Allowed with reduction in capacity for narrow segments

Seismic Information

Allowable Design Categories

ASCE-7 Table 12.2-1, SDPWS 4.3.7.4

All Fiberboard

Sets capacity to 0 for D, E, F

Allows A, B, C

Response modification factor R

Input in Site Dialog, Prompts to change upon load generation

ASCE-7 Table 12.2-1, 12.8.1.1

R -bearing walls

Default 2.0

2.0

R -building frames

Default 2.5

2.5

Deflection amplification factor C_d

Input in Site Dialog, Prompts to change upon load generation

ASCE-7 Table 12.2-1,

12.8.6

C_d - bearing walls

Default 2.0

2.0

C_d - building frames

Default 2.5

2.5

Overstrength Factor W₀

Cannot be overriden

ASCE-7 Table 12.2-1, inc. note b; 12.10.1.1.

W₀ - bearing walls, rigid diaphragms

2.5

2.5

W₀ - building frames, rigid diaphragms

2.5

2.5

W₀ - bearing walls, flexible diaphragms

2.0

2.0 or 2.5

W₀ - building frames, flexible diaphragms

2.0

2.0 or 2.5

*for drag strut force from discontinuous shear lines above, only

Use "shear panels with all other materials category" for R, , C_d , and W₀

Bending Resistance

Reference

SDPWS Table 3.2.1, WFCM Table 3A

Parallel to supports

WFCM 01 Table 3A*

SDPWS Table 3.2.1

* Use WFCM values because SDPWS values are the WFCM ones rounded off.