Load combination classes

Combinations fall into five different classes, with a number of options available for each of the classes:

Combination class	Description	Active	Strength	Service
Construction Stage	Only required for design of composite beams	Not applicable	Not applicable	Not applicable
Gravity	Consists of gravity loads only (self weight, dead, slab dry, slab wet, imposed, roof imposed, snow)	On/Off	On/Off	On/Off
Lateral	In addition to gravity loads, contains lateral loads due to notional loads or wind	On/Off	On/Off	On/Off
Seismic	Consists of gravity and/or lateral loads as well as seismic load cases	On/Off	On	Not applicable
Modal Mass	Only required if you perform a modal analysis	On/Off	Not applicable	Not applicable

Active: Selecting and clearing the option switches the combination on and off for analysis and design.
Strength: If the Strength option is not selected and the combination is active, the combination is not assessed for design.
Service: If the Service options is not selected and the combination is active, the combination is not assessed for deflection.