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In the data group Ignore contribution of...
All gypsum-based materials, fiberboard and lumber sheathing for seismic design
If this setting is selected, gypsum wallboard, plaster materials, fiberboard, or lumber sheathing will not be considered as contributing to the shear strength of any shear walls designed to resist seismic loads.
You would activate this setting if you are doing both wind and seismic design and wish to have the extra shear strength that non-wood-panels provide for wind design, but do not want the penalty of the increased seismic loading due to smaller response modification factor R that is used when non-wood-panel materials are part of the the seismic resistance system.
Materials for which a segment has an invalid aspect ratio when the other side is valid
If this setting is selected, on segments with an aspect ratio of between 2.0 and 3.5, the shear contribution of a material that has a maximum aspect aspect ratio of 2.0 or less is ignored if the material on the other side has a maximum aspect ratio of 3.5. This allows the narrow segment to contribute to shear resistance, as it would otherwise be discarded entirely and considered a non-shearwall segment. If the setting is checked and the contribution of a material on a narrow segment is neglected, that material is included in the shear resistance on other segments on the wall that have aspect ratios less than 2.0.
Rationale For Setting
As SDPWS does not explicitly address this situation, the setting has been included to allow you to exercise your judgment as whether it is legitimate to ignore the contribution of the material with the low aspect ratio limitation on just side of one segment of the wall.
Applications
The aspect ratio limit in SDPWS Table 4.3.2 is 2.0 for unblocked wood structural panels and for non-wood-panels (gypsum-based materials and lumber sheathing), with the exception for wind design that gypsum wall board has a limit of 3.5 when combined with wood-based panels. The limit is 3.5 for blocked wood-based panels (wood structural panels and fiberboard). Fiberboard must be blocked.
So the main application of this setting is for seismic design with blocked wood structural panels on one side and gypsum wallboard on the other side. However, it applies in any circumstance where aspect ratio limits differ on either side of the wall, for example for gypsum wall board which is blocked on one side (limit 2.0) and unblocked on the other (1.5), and the aspect ratio is between 1.5 and 2.0.
Interaction with Allow 3.5:1 Aspect Ratio
When the Allow 3.5:1 aspect ratios setting is unchecked, then this option is unchecked and disabled, as in this case there is no advantage to ignoring the non-wood-panel contribution in terms of avoiding the penalty for a height-to-width ration between 2.0 and 3.5.
Walls entirely sheathed with gypsum-based materials or lumber sheathing
You cannot set this setting, it is always disabled, and is automatically checked when the Rigidity for shear force distribution setting is set to Shear wall capacity. Its purpose is to inform you of that the restriction based on SDPWS 4.3.5.5.1 is in effect, that is, that only wood structural panels and panels are allowed unless the force distribution is based on deflection analysis.
When this checkbox is checked, any wall that has either gypsum or lumber sheathing on both sides, or those materials on one side and nothing on the other side, is entirely neglected for design, deflection calculations, and capacity-based force distribution.
Precedence of Settings
It possible to have All gypsum based materials... for seismic design checked and Materials for which a segment has an invalid aspect ratio... unchecked. In this case, the restriction that all these materials are ignored takes precedence and the program disregards the setting pertaining to the differing aspect ratio limits in narrow segments.
Similarly, it is possible to have Walls entirely sheathed with gypsum-based materials... checked and All gypsum based materials... for seismic design unchecked. In this case, the program ignores the contribution of walls entirely sheathed with non-wood-panels for both seismic and wind design, even though the seismic option is unchecked.
In other words, any restriction indicated by a checked box is imposed, regardless of what other boxes are unchecked.
Output
Design Results Notes
The effect of these design settings is indicated in notes under the Sheathing Materials table
Shear Results Table
If the contribution to shear capacity for any shear line in the table has been ignored due to the Ignore non-wood-panel contribution… settings, then a note appears under the shear results table, referring you to the Sheathing Materials table to find out which wall groups were affected.