Load combinations are combinations of load cases that you set up to reflect particular load situations. For example, if you are designing an office building in the northeast United States, you will want to apply a snow load for the building. But the building may also be in an area where strong winds are experienced in the spring, with or without snow. So now we are looking at three load combinations for which you must account: snow, wind, and snow + wind. Add a live load of people and a dead load of office furniture, and you have many more combinations for different load scenarios.

You can create as many load combinations in the Load Combination Manager as you need, and analysis will be done for each combination. The load combination data is sent with your model to the analytical package for analysis. All you have to do is add the snow load, the wind load, the live load, and the dead load to your model using the Add Member Load and Add Nodal Load tools. Remember that the loads you add must be associated with a load case. The load case is the link between all parts of the load functionality.

Structural discipline seed files can contain load combinations. This means that when you create a model with a seed file that contains particular load combinations, you have already established some of the load combinations that you want analyzed. You can create seed files with different load combinations for different needs (snow, wind, live, dead) and cut down on the amount of load combinations that must be created manually.