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The table below lists the design code provisions applicable to cellulostic fiberboard (CFB) shear wall design for the IBC 2012 and the 2008 AWC Special Design Provisions for Wind and Seismic (SDPWS) .
The table also contains two columns indicating how Versions 7-8 of Shearwalls implemented the provisions, and how the Shearwalls 9/10 program now does. If there was a change between the two versions, it has been indicated in bold.
References to the design codes precede each provision. The symbol T means "Table".
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.
The term "Design code" means that for Shearwalls version 7/8, the value or method used depended on design code chosen. Now only the SDPWS is used.
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Structural Fiberboard |
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Shearwalls |
SDPWS |
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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 4.3.74. |
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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” |
2” |
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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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11ga galv roofing nail |
1½”, 1¾ |
1½”, 1¾ “ |
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Staple 1/2 |
Not included |
Not included |
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Shear Resistance |
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Reference |
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T4.3A |
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½' thickness |
170, 230,260* |
170, 230, 260* |
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25/32" thickness |
170, 230,260* |
170, 230, 260* |
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*depending on 4, 3, 2 nail spacing |
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The shear capacities shown here are the seismic values in table 4.3A divided by 2.0 for ASD design. For wind design, multiply by the 1.4 wind increase factor (see Shear Capacity Adjustments, below) |
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Shear Capacity Adjustments and Notes |
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Reference |
Notes under Sheathing Materials Table |
SDPWS Table 4.3A Notes, 4.3.3 |
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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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Wind Increase Factor* |
1.4* |
Incorporated in Table 4.3A |
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ASD Reduction Factor** |
Values in Table 4.3A divided by 2.0. |
2.0 |
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Note for ASD Factor |
No note |
Note 1 referring to 4.3.3 |
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Aspect Ratio Factor |
See below section |
See below section |
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*Shearwalls multiplies seismic resistances from Section A the table by 1.4 for wind design. The values may be slightly different than those in Section B of the table due to rounding. |
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*The shear capacities shown above are the seismic values in table 4.3A divided by 2.0 for ASD design. |
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Aspect Ratios and Capacity Adjustment |
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Aspect ratio - h/b, bs = segment length, h =height Applies to wall segments or force-transfer piers. ( For more details see Aspect Ratio Limits and Factors ) |
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Maximum aspect ratio |
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SDPWS 4.3.4, Table 4.3.4 |
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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* |
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4.3.4.2, 4.3.3.4.1 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 distribution |
1.09 - 0.09 h / b, |
1.09 - 0.09 h / b, |
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*Applies to segmented and force-transfer walls only; for perforated walls the lengths of the wall segments are factored by 2b,/ h in the calculation of Co . This has the effect of decreasing Co . which is applied to the shear capacity. |
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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 4.3.3.4.1, 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* |
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* Use WFCM values because SDPWS values are the WFCM ones rounded off. |
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