In RAM Elements (and Ram Connection), every load combination is given a type that determines when the load combination is utilized. The figure below illustrates how several different types of combos could be used in a single file.
On the Analysis tab of the Process – Analyze model dialog box, the user indicates if second order analysis will be considered. This is required when using tension-only members or compression-only springs, but may be turned on for any model.
Whenever a second order analysis is performed, the program individually analyzes each selected load case and combination that is checked on the Condition tab.
If second order analysis is NOT performed, then the program only analyzes the selected load cases. The results for all combinations are generated using the principal of superposition, so the user can no longer uncheck individual combos.
Furthermore, if the user opts not to analyze certain load cases, any combinations including those load cases will not have any results available.
The program uses "Service" or "Service-Steel" type load combinations for checking beam deflections. If a model has only "Design" or "Design-Steel" combinations and no service combinations, this feature will not be available. Add at least one service combo (e.g. 1.0 DL + 1.0 LL) to access this feature.
In the lower right hand corner of the program window is the Current Load Condition selection. If the selection is a load case, then you can enter loads for that load case on members, nodes, shells etc. If that selection is a load combination then you can view, but not edit or add to the existing loads.
Change the condition to a valid load case in order to add loads.
Load cases that are associated with dynamic response spectrum analysis should not have any static loads at all.
Yes, you can literally copy the data (ctrl+C) from one file to paste (ctrl+V) into another. You can also copy the data and paste into Excel for future use in another file. Note, the list box data like "Type" will be converted into integers during this process.
You can also save your load conditions from a complete model and then recover those load conditions in a new file. Those options, as well as the option for generating load combinations, are all under the Home Ribbon Menu - Load Conditions group.
Program generated load combinations only include positive factors on lateral wind or seismic loads. If the model is subject to equal magnitude, opposite direction lateral loads, then additional combinations should be manually added using negative load factors on those load cases. If the opposite direction lateral loads should be applied to different members, as is often the case with wind load, then an additional negative direction Load Case should be added instead.
This is contrary to the behavior in RAM Structural System, where rigid diaphragms and linear-elastic braces are the norm.
Yes, in the Load Combinations Generation Dialog, at the lower left is a folder selection which defaults to C:\Program Files\Bentley\Engineering\RAM Elements\ComboGenerators\. in the main module the program will list each file with a .rag extension for selection. These *.rag files are plain text files with simple code to express how load combinations should be generated using constants, Boolean operators (AND, OR), and load types.
For full details on the .rag file format refer to the program help, by pressing F1 while this dialog is open.
For information on load combinations for Connection Design see Ram Connection Capabilities and Modeling
Ram Elements - Tension Only Members