Function
- Convert a load combination containing a number of load cases into a single static load case.
- The conventional linear load combinations, which combine the analysis results of individual load cases, cannot be used if the analysis involves nonlinear elements such as Gap, Hook, Cable, Tension-only and Compression-only elements. For example, a load combination of 1.4D+1.7L needs to be applied as a single load case for the design of a structure consisted of nonlinear elements. This feature lessens the burden of generating such load cases manually. If the ground boundary conditions of a substructure are modeled using compression-only elements, it may not produce accurate results for load conditions that involve uplift pressures or create unstable structures. Therefore, the output values for such load conditions may not be correct, and the results of load combinations that include them may also be unreliable.
- While performing structural analysis using nonlinear elements, all the load cases of a selected load combination should be converted into a single static load case. However, it is difficult to create each static load case from a number of load combinations. Using the "Create Load Cases Using Load Combinations" feature automatically converts a selected load combination into a static load case with a load factor.
Call
From the main menu, select [Load] tab > [Load Type : Static Loads] > [Create Load Cases] group > [Using Load Combinations]
Input
Create Load Cases Using Load Combinations dialog box
Selected Combinations
Defined Combinations
All the entered load combinations are displayed. General load combinations are marked by "CB" Steel Design load combinations by "CBS" Concrete Design load combinations by "CBC" and SRC Design load combinations by "CBR"
Selected Combinations
Select a load combination to be converted into a new static load case. ENV Type load combinations or the load combinations including response spectrum analysis results, which do not show concurrent forces, cannot be selected. Once a load combination is converted into a static load case, it becomes inactive and its result is not displayed.
Load Case & Design Combination Name
Enter a prefix for a selected load combination. Then the load combination name along with its prefix will be used as a name for the new static load case. For example, select "COM" and enter "ST" as a prefix. Then "ST_COM" will be the name of a new static load case.
Design Combination Generate Position
Generate new load combinations from the new static load cases, depending upon the selected load combination type. Auto-generated load combinations will consist only of static load cases with load factor of "1".
In the old version, the static load case corresponding to each load combination was supposed to be created manually. However, in V7.0.1, the program automatically creates new load cases and converts the load combinations into the new load cases. This is particularly useful when the number of load combinations is large.
Select Loads
Among the load cases constituting a load combination, select the load cases to be converted into a new static load case.
In a structural analysis using nonlinear elements (tension-only / compression-only elements or Gap, Hook, Cable, etc.), usual procedures that linearly combine the results of individual load cases cannot be used. In such a case, using a load combination as a load case becomes very useful.