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These settings affect the generation of hold-down forces from shear on shear resisting elements.
Hold-down offset
Here you specify the value of the hold-down offset, that is, the distance between the end of a wall segment and where the hold-down is situated, for all walls in the structure.
If a value is entered that is greater than or equal to ½ a shear wall segment length, the program reverts to the original default value of 1.5” for that segment. It issues no warning in this case, it is evident only by the placement of the hold-down in elevation view and its position as listed in the Hold-down Design table.
Center of wall studs
If this check box is selected, then the hold-down offset is the centre of the end wall stud assembly that you input in Wall Input View or Opening Input View for each wall segment in the structure.
Subtract offset…in moment arm calculation
This checkbox indicates whether the program subtracts the hold-down offset from the wall length when calculating the overturning moment arm.
AWC SDPWS 4.3.6.1.2 (Eqn. 4.3-8) indicates that this distance is not subtracted, however engineering mechanics, particularly when there is only one shear wall on a line, require that it be subtracted. The original default value is therefore to subtract the offset, but you can change this by Save as default for new files.
Include joist depth…in moment arm calculation
This checkbox indicates whether the program includes the floor depth above the wall in the wall height h when calculating the overturning moment arm.
SDPWS 4.3.6.1.2. Eqn. 4.3-8 and the definition of h in 2.3 indicate that this distance is not included, so the original default value is not to add the joist depth. However, as this creates gaps in the static analysis of multi-level structures, you can change this by Save as default for new files.