In MecaStack v5747 we made major changes to the breach stiffener calculations. The output for the stiffener analysis was not very clear or easy to follow and so we attempted to improve upon the formatting of the output. It is now presented in 2 columns which makes it easier to read, and then we also made more heavy use of subscripts and superscripts.
The final change made was to fix some problems we found in the calculations. When a Troitsky or Modified Troitsky breach analysis was performed, then the stiffener was checked for combined bending and axial loading per AISC 360-22/16. We found that these calculations were not always correct, and so we spent considerable time cleaning those calculations and validating the results. We found that there were several instances where the calculations were returning errors (NaN or Infinity), but the table of contents still showed "Green" results, and so unless the user looked at the detailed calculation they didn't realize no result had been calculated. In general when a unity ratio was calculated we have found that when it was in error, it was usually too high. This isn't always the case, but more times than not the values were previously too conservative. Unfortunately there are also examples where the results were too low, or as previously mentioned the calculations failed and the user wouldn't know within investigating the details.
We understand that these kinds of changes can cause major problems on existing designs that were created before these revisions/corrections were made. We apologize for the inconvenience, but hope you understand that when we find a mistake in our calculation then we are obligated to fix it. If for some reason you decide that you prefer to use the results prior to these corrections being made, then you can download a specific version in one of two ways:
1) Within MecaStack go to help and then select "Rollback to previous Update".
2) If you don't want to remove your current version, and instead install a 2nd version that is older. Then you can download directly, and during installation give the folder name a different name (i.e. mecastack_v???).
https://www.mecaenterprises.com/downloads/software/mecastackinstallation_v5746.exe
(Replace the version v5746 with the version you desire).