Engineering Design and Deflection Analysis

Important Note – These are descriptions to changes implemented in WoodWorks Shearwalls for version 9.1 and may not reflect current behavior.

1. Wind Capacity Increase Factors (Change 99)

   We have removed the ability to enter the Wind Capacity Increase factors in the Design Settings, because these inputs have become outdated. They have also been removed from the Design Settings output echo. If a file created with a previous version has factors other than those in the SDPWS and NDS design codes, the factors are changed to the design code values.

   1. Allowable Shear Stress Adjustment

      The allowable shear stress adjustment is showing the ratio of capacities for wind design vs seismic.  This was more important for the older IBC (2306.3 in 2009, 2306.3.2 in 2006) that allowed the increase.  The IBC now refers to the SDPWS, which has separate columns for wind and seismic capacities. 

      Note also that the 1.4 increase doesn’t pertain to lumber sheathing, so this removes this complexity from the program, in which the program used to factor lumber sheathing by the ratio of 1.4 and the entered value.

   2. C&C Load Duration for Nails and Sheathing

      Removing this eliminates confusion between the 1.6 duration factor increase vs. the 1.6 reduction from the published nominal values in SDPWS table 3.2.1 to the ASD values. Both of these factors are taken care of internally now.

      Although NDS 2.3.2 refers to these as “frequently used values” and presumably optional, and WoodWorks Sizer allows them to be modified, Shearwalls does not allow the duration factors for MWFRS to be changed, so it is inconsistent to leave them in for C&C design.

2. Tolerance in Determining Segment Loading (Change 92)

   If the force on a segment is less than ½ pound, it is considered to be zero and deflection and hold-down calculations are not made for that segment. Previously the tolerance was 0.1 lb, which led to segments that showed a zero force having significant deflection.

3. Elongation Override for Unloaded Segments (Change 93)

   The program was assigning a deflection due to hold-down elongation for segments that attracted zero loading when that elongation was taken from the override in the Design Settings. The program now assigns zero elongation in that case.

4. Design Cancel (Change 100)

   Fixed “Cancel” of design such that it cleans up the what it is doing on the current floor and then exits. Previously it was doing large amounts of unnecessary processing, and the box would freeze on the screen, but not do anything or affect the program.