Load Generation and Distribution

Important Note – These are descriptions to changes implemented in WoodWorks Shearwalls for version 10.3 and may not reflect current behavior.

1. C&C Wind Load Combination (Bug 2820)

   The wind load combination factor for C&C design of sheathing strength and nail withdrawal was not updated for ASCE -7 10 for version 10, it remained at 1.0 when it should be 0.6. This has been corrected.

2. Hold-down Offset using Center of Wall End Studs (Change 165)

   Since typically the centre of the end stud assembly is the location of the centroid of the hold-down force, we now allow you to use the distance from that location to the end of the wall as the hold-down offset used for moment arm calculations.. A checkbox in the Hold-down settings is used to indicate you want to use this value, allowing a different value for each wall in the structure according to the number of end studs entered in Wall input view.

   When drawing, the program now draws the tension side hold-down at the full stud thickness from the wall end, because it depicts the bracket, not the center of the bolt through the studs.

3. Hold-down Force Accumulation Tolerance (Change 169)

   The program now accumulates hold-downs forces from the floor above with the one on the floor below when these forces are that are offset by as much as 1.5 " in plan. This is the minimum distance from wall end.

4. Vertical Distribution of Seismic Forces Coefficient k (Bug 2515)

   The following problem relates to the co-efficient k from ASCE 7 12.8.3, which is used to distribute forces to the shearwall levels.

   1. Use of k to Distribute Forces to Levels

      Despite the fact that the program output the value k in the log file, a value of 1.00 was always used in the formula 12.8-12 for C_vx. However, a value of other than 1.00 corresponds to structures greater than 75 feet in height and is quite rare in practice. Nevertheless, the program now calculates the value k used for C_vx for structures with a period greater than 0.5.

   2. Period T used to Calculate k

      The maximum period T_max defined in 12.8.2 was mistakenly used to determine k. Now the approximate period T_a is used. The optimal approach would be to use the actual period T as input in the Site Dialog, however due to the small chance that there would ever be a period greater than 0.5 leading to a k other than one, it was not regarded as worth the effort to implement the calculation of different k and C_vx values in each building direction.

5. Nonsensical Seismic Loads on Certain Windows 8 Computers (Bug 2830)

   For certain Windows 8 installations, for any structure, all seismic loads were astronomically high nonsense values. This has been corrected.