When assessing hydrostatic loads, I have found that STAAD does not treat them properly. If a hydrostatic load is applied in one direction and a different hydrostatic load is applied in the opposite direction, the shear force diagrams are wrong. To get around this on a simple project, I manually combined the load cases. However, for a more complex project, this is not viable.
Using the combination or the repeat load makes no difference to the results.
Any thoughts?