Load combination properties

Load Combination Name The label used to identify the load combination.

Combo Type The choices are:

Single: this is the standard type.
Lateral Group: this is used for a floor that is part of the lateral force resisting system [especially mat foundations (rafts)].

Note: The primary purpose of Load Combination types is to reduce the number of lateral load combinations. A secondary purpose is to provide easy enveloping for results such as soil bearing pressure.

Analysis Type The choices are:

Linear: this is the standard type.
Zero-Tension: these load combinations do NOT have alternate load factors and never consider pattern loading or the "Don't Reduce Integrated M and V Due to Sign Change" option for span segments and design sections (See Using the Don't Reduce Integrated M and V due to Sign Change option ).

Active Rule Sets These control which rule sets are used for design calculations. Up to six active rule sets can be associated with each load combination. See Selecting Design Rules for further explanation.

Load Factor The factor applied to a particular loading in the load combination.

Alternate Envelope Factor You should only use these if you fully understand the principle involved. Do not set these factors to zero without understanding their use. If you are unsure then set them to equal the corresponding load factors. See About alternate envelope factors .