When analyzing a model, all spring hanger supports were set to "Undesign", forcing AutoPIPE to calculate the correct spring hanger based on analysis settings during a Hanger Selection analysis.
Perform a Static Analysis and note the results for all restraints in the model.
Next, uncheck the "Undesign" check box on a few, not all, of the spring hangers and rerun the Static Analysis again.
Compare the results for Restraint reactions to the previous analysis results, note that they are different, why?
When ever faced with a problem like this, comparing the results of one analysis to another analysis, best to create a complete model input listing report and complete model output report with all sub reports Enabled / checked ON, then compare these reports to be sure that everything is as suspected or if items were inadvertently changed by the user or program. See the following WIKI here to create and compare these reports.
In this case, pay special attention to the remaining spring hangers that still have "Undesign" enabled / checked ON. Be sure to compare the results of the Spring Hanger selection reports for these spring supports to the original report values; note the difference, WHY?
The difference is based on how the Hanger Selection Procedure process is performed, See AutoPIPE help for Hanger Selection Procedure "hot load design method" or "cold load design method". This will provide detail of how the the Hanger analysis is performed. The results from the hanger analysis is then used in the Static Analysis. In the first go around where all spring hangers were set to "Undesign", the program calculated the correct spring rate at each support. On the second go around after some of the spring supports were removed from the hanger selection, this affected the Hanger Analysis procedure and thus results are different .
Spring Hanger Selection