Set additional parameters for seismic combinations

You can define additional parameters for specific combination cases.

1. Click Loads Manual combinations. The Combinations dialog opens.
2. Select the combination for which you want to set additional parameters from the Combination list.
3. Click Change. The Combination Definition/Modification dialog opens.
4. Click Parameters The Combination Parameters dialog opens.
5. For a seismic analysis, select the type of seismic combination (SRSS method - Square Root of the Sum of Squares; CQC method - Complete Quadratic Combinations, 10% method, 2SM method - double sum). These options are available only if a case was defined for a seismic analysis.
6. Assign a Nature to the combination (dead, uniform, live, snow, wind, temperature, accidental, or seismic), similar to assigning nature to a simple load case. The nature should be specified, if a given combination participates in subsequent automatic combinations defined using the Manual combinations - generate option from the Load Case Code Combinations dialog.
7. Decide whether to create a Quadratic Combination. If this option is active, it means that the results for this combination will be calculated as the square root of the sum of squares. For example, if the combination consists of three cases a, b, and c, and the reaction force Rx is to be calculated, then the value of the reaction force in a quadratic combination is determined by the following formula: .
8. Click OK.