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The hold-down displacement contribution to deflection at each interior segment of the force-transfer wall is calculated as if there was a hold-down device at each opening, even though they are not present in force-transfer walls. The wall anchorage term in the equations for deflection is calculated as follows:
Shear Overturning Force
The shear overturning force is calculated using the reduced moment arm of those segments that are considered to extend from the bottom of the opening to the top of the wall. For full-height end segments, the wall height is used as the moment arm.
Dead and Wind Uplift Force
Dead loads and wind uplift loads on the same level as the segment are distributed to the segment ends for the purpose of deflection calculations. Dead and wind uplift loads over openings are distributed to the fictitious hold-downs at the sides of the openings, as if it was a segmented wall.
Forces from Upper Levels
Dead, wind uplift and overturning hold-down forces from floors above are included in the calculation of hold-down deflection if the hold-down forces on the wall above and on the wall below are at the same location; that is, these segments behave as segmented walls do in this regard.
Height-to-Width Factor
The factor h/b in the wall anchorage term uses the reduced segment height h for those segments considered to extend from the bottom of the opening to the top of the wall. For full-height end segments, the wall height is used.
Hold-down Devices Used
To determine hold-down elongation, the virtual hold-down devices used for the left end of all openings are the real hold-downs selected for the left end of the wall, and those used at the right end of openings are those selected at the right end of the wall.
When calculating deflections in the opposite direction, the hold-downs are flipped, so that for one actual force direction, the same hold-down devices are subjected to tension in all the deflections that are averaged to give the resulting wall deflection.