The Load Combinations Mode allows you to manually define or generate a set of custom load combinations. The member forces and other analytical results from those combinations of load cases can then be displayed on screen or reported. If your model is made of steel frames and if you are going to be using the RAM Frame - Steel Mode for the design of those frames, then there will be a separate set of load combinations defined in that mode which are used only in the steel member design. To initiate the Load Combinations Mode:

• Select Mode > Analysis > Load Combinations.
  

The mode will change and some of the menu options will be affected.

• Select the new menu item Combinations > Custom Combinations.

The program can generate load combinations using templates. The templates are text files stored along with the rest of program tables. The templates are grouped in categories like Concrete combos, Soil Combos, LRFD combos, etc. Those templates are further broken down by building code (at least in the US).

• In the Custom Load Combinations dialog box that opens select CONCRETE_ACI (CONCRETE_BRITISH) as the template ID.
• In the Code for Combinations select ACI 318-08 (BS8110 1997).

Different codes modify load combinations in various ways and the program doesn't always know which approach to take. In the case of ACI 318-08 load combinations, the program needs to know if the seismic load was initially defined as a service level load case or an ultimate load case. In our case, the ASCE 7-05 seismic load case we defined was an ultimate level load case.

• Uncheck the first box labeled Seismic is Service. Multiply by 1.4
• Leave the second box checked, this model did utilize the Kd factor in our wind load case (for British code users check the box labeled Use 0.9 Instead of 1.0 for Dead Load Factor).
• Click [Generate] and the program will generate the full set of code combos. This could result in several hundred load combinations. The new load combinations are automatically checked to be Used. You can uncheck any of the boxes in the "Use" column to inactivate a particular load combination without deleting it entirely.

Now the analysis results of the selected load combinations can be viewed using the same commands as described in previous sections.

• Select Report > Member Force Envelope > Single.
• Select any lateral member.

The program will generate a report of the minimum and maximum forces in that member for any load combination. The envelope values reports are algebraic. In other words, the minimum moment might be a bigger negative number than the maximum, positive moment. Note that the maximum value may occur at the end or at any point along the length of the member. The location of the maximum force, along with the load combination which produces it are both reported.

• Select Mode > Analysis > Load Cases to return to that mode.

You have completed the analysis of the structure for each of the individual load cases. You will now proceed to design your frame members using combinations of those loads.