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The following inputs in the Structure Input form that allow for input of parameters that apply to all hold-downs on a single building level.
Length Subject to Shrinkage
The distance between extreme hold-down fasteners spanning perpendicular-to-grain wood that contributes to hold-down shrinkage. Typically the floor joist depth (floor depth - flooring thickness) plus the thickness of one bottom wall plate and two top plates on the lower level. Shrinkage is calculated by this distance x .002 x difference in fabrication and in-service moisture content percentage as input in the Design Settings.
You can set a default value for this length in the Hold-down Settings dialog, based on a proportion of the floor joist size plus an extra amount.
Anchor bolt length
This indicates the required length of the hold-down anchor bolt, if one exists for a particular hold-down.
It is the length between nuts of the threaded rod or bolt attaching the two brackets of a double bracket hold-down, or for a bolt securing a single-bracket hold-down into the foundation or other support, from the upper nut to the foundation surface.
Used to calculate the elongation of the part of the bolt that is in excess of the Max length for given displacement in the hold-down database. For double brackets, it is the length in excess of twice the maximum database length.
Typically this is the Length subject to shrinkage plus the flooring thickness, plus any gap between hold-down brackets and wall plates. However, in some situations it could be quite different, for example when wood I-joists are used. The I-joist web is included in the anchor bolt length but not in the length subject to shrinkage.
Context sensitive help
Each of these fields have context-sensitive help explaining their use, accessed via the question mark box at the top of the dialog box.