Load case vs combination?

[StructureMan44]

What is the difference between load cases and combinations? When doing calcs by hand I only use load combinations (1.2DL + 1.6LL, etc.) At my firm when using software we enter both but the load cases are the load combinations multiplied by 1.

 

[TehMightyEngineer]

My understanding of the terminology and usage is load case is the various different loading permutations applicable and are typically unfactored. For example, the various cases of wind loads (8 directions, torsional load case, max internal or max external pressure, etc.). The load combinations are the IBC/ASCE load combinations where you combine the loads from one load case into the resulting factored design load.

So, for example you might have the following load combination for multiple live load cases:

1.2DL + 1.6LL(case 1)
1.2DL + 1.6LL(case 2)
1.2DL + 1.6LL(case 3)
etc.

Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries

http://www.americanconcrete.com

 

[IronCityEngineer]

Load cases are the types of loads that are applied to the structure: dead, live, wind, ice, snow

Load combinations are how the load cases are combined.

 

[Once20036]

What's the software that you're using?
What load cases are defined?
What load combinations defined?

If you're inputting load combinations with a 1.0 load factor(1.0*Dead +1.0*Live), it may be for bearing pressures under foundations. Essentially inputting both ASD load combinations and LRFD load combinations.

I believe this doesn't make a huge difference until you get into non linear effects. For small, squat, simple buildings with low lateral forces, it may just be terminology.