The table below lists the design code provisions applicable to cellulosic fiberboard shear wall design for the AWC Special Design Provisions for Wind and Seismic (SDPWS) and ASCE 7. One column is for the design code provision, the other is for the implementation in Shearwalls; in most cases they are the same.
For some provisions, more detailed information is found in a table dedicated to the provision in another topic that is cross-referenced in this table.
Structural Fiberboard |
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Shearwalls |
SDPWS / ASCE 7 |
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Major References |
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SDPWS 4.3.7.4 and Table 4.3A |
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Wall Construction |
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(for more details, see table fable for Wall Construction ) |
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Reference |
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SDWPS 4.3.7.4. |
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Surface |
Either or both |
Either or both |
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Orientation |
Vertical |
Vertical |
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Blocking |
Blocked |
Blocked |
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Max Stud Spacing |
16” |
16" |
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Stud Thickness |
2” nominal |
2” nominal |
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Sheathing and Fasteners |
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Sheathing thickness |
½”, 25/32” |
½”, 25/32” |
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Fastener spacing (for more details, see Fastener spacing table) |
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Edge spacing |
2”, 3”, 4” |
2”, 3”, 4” |
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Interior Spacing |
2”-6” |
6” max |
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Fastener types and sizes ( for more details, see Table for Fastener type and lengths |
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Common nail (not box) |
Not included |
not included |
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11 ga galv roofing nail |
1½”, 1¾ |
1½”, 1¾ “ |
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ASD Shear Capacity |
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Reference |
Tabulated values divided by ASD reduction factor |
SDPWS Table 4.3A , 4.1.4, unfactored |
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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 |
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Capacities given are for 4", 3", 2" panel edge nail spacing. Same capacity for both sheathing thicknesses. |
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Shear Capacity Adjustments and Notes |
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Reference |
Notes under Sheathing Materials Table |
SDPWS Table 4.3A Notes, 4.3.5 , 4.1.4 |
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Specific Gravity (G) factor |
1 - ( 0.5 - G) |
1 - ( 0.5 - G) |
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Note for G |
Note 1 |
Note 3: |
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ASD Reduction Factor |
Incorporated into design values |
SDPWS 4.1.4 |
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Wind design |
2.0 |
2.0 |
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Seismic design |
2.8 |
2.8 |
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Note for ASD Factor |
No note |
Note 1 referring to 4.1.4 |
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Aspect Ratio Factor |
See section below this one |
See below section |
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Perforated Wall Factor |
Gypsum only allowed in combination with wood structural panels on perforated walls; refer to Wood Structural Panel Provisions |
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Aspect Ratios and Capacity Adjustment |
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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 ) |
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Maximum aspect ratio |
Aspect ratio shown in Elevation view for each segment. |
SDPWS 4.3.3, Table 4.3.3 |
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Adjusted |
3.5:1 |
3.5:1 |
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Unadjusted |
1:1 |
1:1 |
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Shear Capacity Adjustment |
If not 1.0, shown in Elevation view. Also shown in Shear Design Results. |
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Segmented or FTAO walls* |
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4.3.3.2, 4.3.5.5.1 Exception 2 |
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Capacity-based force distribution |
0.1 + 0.9 b/ h |
0.1 + 0.9 b/ h |
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Deflection-based force distribution |
1.09 - 0.09 h/b |
1.09 - 0.09 h/b |
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Perforated walls** |
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SDPWS 4.3.5.6, 4.3.3.4, Eqn. 4.3-5 |
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All types of force distribution |
Sbi /Sb; bi = 2b/h when h/b > 2 |
Sbi /Sb; bi = 2b/h when h/b > 2 |
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*Applies to shear wall segments with aspect ratio between 1.0 and 3.5. |
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**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. |
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Combination of Sheathing Capacities |
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For more details, refer to Combination of Sheathing Capacities, |
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Reference |
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SDPWS 4.3.5.4, , 4.3.5.4.2 Exception |
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Identical materials on both sides |
Add capacities |
Add capacities |
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With fiberboard with different specs on other side |
Vwc=Kmin Gac |
Vsc =Kmin Gac |
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With non-fiberboard on other side for seismic design |
Twice weakest or strongest |
Twice weakest or strongest |
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With gypsum wallboard or gypsum sheathing board on other side for wind design |
Add capacities |
Add capacities* |
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With lumber siding, wood structural panels, or lath/plaster on other side for wind desigm |
Twice weakest or strongest |
Twice weakest or strongest |
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Twice weakest or strongest: vn(c) = max ( 2 x min ( vn(1) ,vn(2)) , max( vn(1),vn(2) ) ) |
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Combination of Apparent Stiffness Ga |
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For more details, refer to Combination of Sheathing Stiffness |
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Reference |
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SDPWS 4.3.5.4 |
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Identical materials on both sides |
Add stiffnesses |
Add stiffnesses |
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With fiberboard with different specs on other side |
Add stiffnesses |
Add stiffnesses |
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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 |
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Twice weakest capacity or side with strongest cap: Ga(c) = max (2 x Ga (min ( vn(1) ,vn(2))) , Ga (max( vn(1),vn(2) ))) |
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Permissible Force Distribution Method |
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Refer to Shear Force Distribution Methods for more a description of these methods and how they are selected. |
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Reference |
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SDPWS 4.3.5.5.1, inc. Exception 2, |
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Deflection-based distribution |
Allowed |
Allowed |
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Capacity-based distribution |
Aspect ratio adjustment applied to narrow segments, see above |
Allowed with reduction in capacity for narrow segments |
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Seismic Information |
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Allowable Design Categories |
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ASCE-7 Table 12.2-1, SDPWS 4.3.7.4 |
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All Fiberboard |
Sets capacity to 0 for D, E, F |
Allows A, B, C |
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Response modification factor R |
Input in Site Dialog, Prompts to change upon load generation |
ASCE-7 Table 12.2-1, 12.8.1.1 |
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R -bearing walls |
Default 2.0 |
2.0 |
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R -building frames |
Default 2.5 |
2.5 |
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Deflection amplification factor Cd |
Input in Site Dialog, Prompts to change upon load generation |
ASCE-7 Table 12.2-1, 12.8.6 |
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Cd - bearing walls |
Default 2.0 |
2.0 |
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Cd - building frames |
Default 2.5 |
2.5 |
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Overstrength Factor W0 |
Cannot be overriden |
ASCE-7 Table 12.2-1, inc. note b; 12.10.1.1. |
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W0 - bearing walls, rigid diaphragms |
2.5 |
2.5 |
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W0 - building frames, rigid diaphragms |
2.5 |
2.5 |
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W0 - bearing walls, flexible diaphragms |
2.0 |
2.0 or 2.5 |
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W0 - building frames, flexible diaphragms |
2.0 |
2.0 or 2.5 |
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*for drag strut force from discontinuous shear lines above, only |
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Use "shear panels with all other materials category" for R, , Cd , and W0 |
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Bending Resistance |
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Reference |
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SDPWS Table 3.2.1, WFCM Table 3A |
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Parallel to supports |
WFCM 01 Table 3A* |
SDPWS Table 3.2.1 |
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* Use WFCM values because SDPWS values are the WFCM ones rounded off. |
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