We have tried to compare the results of V22.04.00.40 & V22.05.00.131 prior to shift to the latest update - same STAAD file (no modifications).
As shown in the snapshot, significant post-processing output differences were found.
The largest differences noted were on the Wind Load Cases.
The STAAD Generated Wind Load values, however, were found to be the same.
So it must be a change in the calculation/routine that caused the significant difference.
Can anyone please clarify the wind load calculation procedure for Update 5?
Could you please attach the related STAAD.Pro model?
I have uploaded the file through the Communities Secure File Upload.
I just checked the primary loads for the cases mentioned since the trial item was big, but most likely the results are not far from what I originally reported. And for all the cases done, the significant differences was consistently ONLY in the Wind Load Cases. I do hope we can clarify this matter soon. Thank you!
Maybe I am misunderstanding this issue - what the percentage difference in the results which you are comparing? You keep calling it as significant, but I can find a very small differences only. Maybe I am comparing different things than you. Could you please clarify?
The summary I have shared is the differences of the post-processing outputs (support reactions, node displacements, beam end forces) from STAAD. From this table, we expect at most 0.005 differences in values from different versions. But for the comparison of Update 4 & Update 5 we got (based on the sample) an axial beam end force value which is +/-0.95kN in the Primary Load Case alone. This results to +/-400kN axial force after the direct analysis. Thus, members that previously had an Update4 ratio of 0.7 are now failing in Update5 due to the increase in forces. I hope that clarifies the matter, please let me know if it is still unclear :)
+/-400 kN difference occurs due to a defect in the TRUSS specification as I mentioned previously. If you comment out the TRUSS specification from the model and run the analysis again, you will see that the difference in member forces is minimal (not more than 0.3%) and this leads to identical design results.
I have uploaded a file yesterday which includes a tab of the comparison of results without the TRUSS specification as you have recommended earlier, but the results are not far from the initial findings.
For reference, I have also tried to remove just the temperature load and to have the temperature load but no TRUSS Specification
If it were the TRUSS specification, the difference should not be in the Wind Load Cases only. I was thinking, it might have been somewhere in the routine & not the generated wind load itself that caused the difference.
Basically we are talking about 2 different issues:1) The TRUSS specification issue, which leads to significant changes between the results in some loads cases.2) Wind Load generation issue, which leads to a very small differences between the applied wind load.If we do not use the TRUSS specification and compare the analysis results (i.e. member forces) you will see that the differences between the forces are very small (for primary cases and combinations) and these are due to issue #2. However, the design results (utilization ratios) will be identical between different versions WITHOUT TRUSS spec.