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Elongation and Slippage Combined as Single Displacement
Indicates that the published displacement includes deflection from fastener slippage and from elongation of brackets or straps, and that the published capacity includes the wood connection capacity horizontal fasteners. Otherwise, the published displacement is from elongation only and capacity is the tensile capacity of the hold-down - slippage is calculated separately by Shearwalls, and the wood connection is not considered.
Typically published displacements contain values which depend on the dimensions of the end studs, so that several Displacement records must be entered. For elongation-only values, only one record is required, which applies to all stud sizes.
Elongation for Connector Only (without Anchor Bolt)
Indicates that the elongation of the anchor bolt is not included in the published elongation value and the tensile capacity of the bolt is not included in the published hold-down capacity. If checked, the elongation of the entire anchor bolt is calculated using the bolt length as input in the Structure dialog on each level, and the tensile capacity of the bolt is not considered.
This cannot be used for those hold-downs which combine displacement and slippage in one published value, which also includes anchor bolt elongation.
Shrinkage Compensating Device
Indicates that the hold-down a mechanical device to adjust for wood movement, so that the wood shrinkage calculation and wood crush component are not included in the hold-down displacement. When checked, displacement is from fastener slippage and hold-down elongation only.
Always use Elongation at Maximum Capacity
Checking this box will cause the program to use the displacement or elongation at maximum capacity as the vertical hold-down displacement regardless of the force at the hold-down location. Otherwise, the program will factor the displacement by the proportion of actual to maximum force at the hold-down.
Using the maximum hold-down force is sometimes recommended because of the non-linear aspect of the slippage.
Checking the box is conservative with respect to shear wall deflection and the story drift check, however for low uplift force it may create more deflection than actually exists, and correspondingly lower rigidities for load distribution to that shear line, which is non-conservative with respect to shear wall design.