Envelope (Low-rise) Load Model

Important Note – These are descriptions to changes implemented in WoodWorks Shearwalls for version 10.0 and may not reflect current behavior

ASCE 7 has restored the model of low-rise loading in figure 28.4-1 to have the same nomenclature and set of load cases that it did with ASCE 7-98 and before, and that was implemented in the versions of Shearwalls before 2004c , released in July, 2006. Version 10 restores these load cases and nomenclature.

The main change to this model is that the MWFRS in the transverse to ridge direction has 2 separate load cases, Case A and Case B. Preciously what is now Case A was applied only to the transverse direction and Case B only to the longitudinal direction. Case A in the longitudinal direction creates opposing shearline forces that tend to cancel out and rarely govern when compared to Case A, but this case has been restored to the program for completeness.

1. End Zone Changes
   1. Longitudinal End zone

      The longitudinal load Case B end zone width has been reduced to ‘a” rather than 2a. ‘a’ is defined in Note 9.

   2. Transverse End zone

      There is now an end zone for the load case B on the transverse surface that has been implemented..

2. Plan View
   1. Load Arrows

      The large load arrows in plan view are now shown at an oblique angle which indicates the low rise wind range for that case.

   2. Show menu

      The term MWFRS Direction is changed to Orientation, and it no longer controls whether it shows transverse or longitudinal, instead just acts as it does for all-heights in turning off one direction to reduce clutter.

      The Wind Load Case now allows you to choose between Case A and Case B , whereas previously it was disabled for low rise..

      Equivalent changes have been made in the Loads and Forces settings.

   3. Case A Side, Case B End

      A new option has been added to show the loads for Case A in the longitudinal direction, and Case B in the transverse direction, as these are the cases that will ordinarily govern for design. In this case, the program shows exactly what it did for Version 9, with the load arrows appearing at right angles.

3. Load Input

   The load list now shows A or B under the heading A/B rather than T or L under T/L

4. Output

   In the following tables, and in the log file output, the Load Case T or L is changed to A or B

   Wind Shear Loads.

   Hold-down Design

   Drag Strut

   The explanations in the legends have been changed accordingly.

5. Windward Corner Nomenclature

   In the Show menu and in the Hold-down table legend, “Wind Reference Corner” has been changed to “Windward corner” to agree with current ASCE terminology.