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Deflection Load Combinations from IBC 1604.3
Use L + 0.5D for deflection (Note d)
When this check box is checked then, for dry service conditions, the deflections for the load combinations D + L, D + Lr, and D + L + Lr are calculated with the dead load component multiplied by 1.0 for CLT and 0.5 for all other materials. For wet service conditions the dead factor is 1.0. This load combination is the short-term live load plus the creep component of dead load.
The live roof Lr load type is mentioned in the note, but not in the table heading.
All other load combinations, such as D + 0.75 (L + S), remain unchanged; the full dead load is used for deflections in those combinations. The reaction, shear, and bending are not affected for any load combination.
The program renames the setting to Use L+ D when CLT is selected or wet service conditions are in use..
Note d says that this provision is not to be used in conjunction with long term loading from NDS 3.5.2, so if this box is checked, the creep factor option is disabled set to 1.0 long term loading. Note that the dead load, including creep, for long term deflection is 1.5 D for dry service conditions and 2.0 D for wet service and CLT, so this checkbox offers you a choice of designing for total deflection using all long-term deflection or designing for short term deflection + dead load creep.
This setting can be saved as default for new member files, and is saved for each member file. The original default value is that it is checked.
.42W for C&C loads (Note f)
This implements IBC Table 1604.3 Note f, which says that C&C wind loads can be factored by 0.42, rather than the usual 0.6. This entails an additional factor of 0.7. By checking this you are saying that the wind loads on the member are component and cladding loads. When the setting is checked, the deflections for all load combinations containing a wind component are calculated with a 0.7 factor multiplied by the factor(s) that are currently applied to the wind component (0.6 wind factor multiplied by either 0.75 or 1 factor for combination with other non-dead loads).
This setting does not apply to Concept mode, because Concept Mode’s structural members are assumed to be part of the main wind force resisting system with respect to any vertical wind loads that are placed on the building, and Concept does not handle horizontal wind loads
This setting cannot be saved as default for new member files, but is saved for each member file. The factory default value is that it is unchecked.