I believe there's a problem in defining the modal mass in the physical modeller, since it allows taking the mass out of the gravity cases, and you cannot add additional masses as from snow or live loads, it was achievable in staad update 8 but isn't the same in update 9. kindly guide me how this can be solved without detaching the physical model?
Ahmed S. Kamel
Follow the process explained in the STAAD.Pro Physical Modeler Help manual section Applying Loads > Working with Load Groups > To add a mass model load group.
thanks for your answer, so if I need to add 50% of the live load should i make a new load group and specify it as Live, and then so for the rest of the loads? as shown in picture?
then it's obligatory to define load category in the load cases tab? if I defined the Load group as you see in the previous picture, will the software consider both "mass that comes form the dead load" and convert the live load into a mass multiply by 0.5 this is the modal mass?
No. For the mass Load Group the Category must be set to Mass. Once this group is created, you need to select that Load Group as an active Load in the Loading menu. Once this Load Group is selected as active Load, you then add loadings in the Nodes, Members or Surfaces menu. If you want to copy the loading from some specific load case which has been already entered, you can use the Add Loads feature in the Loading menu. Also, you need to remember that these loadings (masses) should be entered in all 3 global directions, so you can easily do that (by using the copy/paste commands) in the loading spreadsheets (Spreadsheet menu). You can review this video for more details: www.youtube.com/watch
the modal mass is created in 3D, by adding the combination factors of the loads in the load cases is defining which loads are taken in the modal mass? kindly find these two pictures
Load Group Factors are used to include some specific Load Group (Reference Load) in some specific Primary Load Case with the entered factor.