Release Notes Simpson Strong-Tie Weak Story Tool Software

  • Fixed a bug in which the program crashed when the user would try copying and pasting a diaphragm shape from one floor to another.

  • Fixed a bug in which the program allowed the user to enter an invalid Hmin for a Simpson frame and save it but caused the program to crash when the frame selection form was re-visited.
  • Fixed a bug in which the top print margin increased each time the document was re-opened and printed.
  • Modified messages about eccentricity to follow Guidelines more closely.
  • Fixed a bug in which changing the Simpson frame of an existing assembly would not take effect immediately.

  • Fixed a bug in which pasting walls sometimes caused the program to crash.

  • Fixed a bug in which the adjustment factor accounting for differences in wall heights within the same level was not applied correctly. This only affected models with walls that overrode the story height.
  • Fixed a bug in which conflicting status messages were reported for buildings with adequate performance in the existing condition.

  • Fixing a bug in the calculation of the allowable eccentricity of the retrofitted structure, which in some cases led the program to approve retrofitted structures with eccentricity greater than allowed by the guidelines.
  • Fixing a bug in which entering incompatible units (e.g., in the Perforated Area text box) would cause a crash.

  • Set up summary charts so that legend appears on printout.
  • Corrected eccentricity requirement for retrofitted structure. It had been 5% but should have been 10% per Guidelines section 6.3.1.

  • Corrected issue in which trying to plot backbones of walls without assemblies assigned would cause a crash.
  • Corrected issue in which having no torsional strength would allow analysis and would cause a crash.
  • Corrected issue in which a file with many images would crash on opening.
  • Corrected issue in which a building with too much strength in the existing condition may mistakenly be indicated as adequate in the status label.
  • Corrected issue in which saving a .wst file did not change the extension to .swst.
  • Corrected issue in which trying to print would delete analysis results.

  • Corrected issue in which eccentricity validation for the X and Y directions was flipped (previously validation eccentricity for X direction was attributed to the Y direction in the Summary Log and visa versa).
  • Corrected issue in which a building that could not be classified as having a weak story in its existing condition would be reported in the Executive Summary portion of the Summary Log as being adequate, while the detailed summary indicated that other retrofit measures were required.
  • Corrected issue in which changing printing options would delete analysis results.
  • Corrected issue in which trying to insert a large image would cause WST to crash.

  • Corrected issue in which with scaling an image too large would cause a crash or hang-up.
  • Corrected printing issue with sheathing layer and assemblies charts.

Weak Story Tool
with Simpson Strong-Tie® Strong Frame® Moment Frames


Category: Lateral Systems
Updated: November 30, 2016
Size: 8 MB

Release Notes   Requirements

The Weak Story Tool with Simpson Strong-Tie® Strong Frame Moment Frames is an enhanced version of the original Weak Story Tool shown in The Federal Emergency Management Agency (FEMA) document FEMA P-807, "Seismic Evaluation and Retrofit of Multi-Unit Wood-Frame Buildings with Weak First Stories". FEMA P-807 describes procedures for the analysis and seismic retrofit of vulnerable wood-frame buildings that are common in Northern and Southern California and the Pacific Northwest. The Weak Story Tool assists in performing the analysis outlined in FEMA P-807 with the aid of a CAD interface to account for the locations and structural properties of the various lateral load resisting elements before and after retrofitting. The enhanced Weak Story Tool with Simpson Strong-Tie® Strong Frame Moment Frames combines the convenience of designing a variety of retrofit solutions that include Strong Frame® special moment frames with a simplified method for cost evaluation.



  • Familiar functionality built on FEMA’s original Weak Story Tool featuring a CAD-like graphical interface to layout walls and Strong Frame® Special Moment Frames
  • Seamless sizing, and specifying of standard and customized Strong Frame® Special Moment Frames and the appropriate Yield-Link™ Structural Fuse within the tool for FEMA P-807 solutions
  • Building analysis summaries including evaluation data, shear-wall and moment frame backbone curves, and performance data
  • Save electronic files that can be opened in the Strong Frame® Moment Frame Selector software for anchorage design
  • Ability to enter building properties and geometry for more than one level
  • Calculates and tabulates structural properties and locations of sheathing assemblies and moment frames
  • The option to choose the probability of exceedance for retrofit acceptance from 5% to 50%

System Requirements

  • Microsoft Windows® XP or newer
  • Microsoft .NET Framework


Our Technical Support Department hours are M–F from 8am–5pm Pacific Time.

In most cases you will receive a response in two business days or less.

For help, please email wst-help@strongtie.com.

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© 2015 Simpson Strong-Tie Company Inc.