Generate load combinations

This window is a small editor that lets you enter combinations that will generate the model based on their category. According to the building code which has been taken, the user can create a list of all required combinations in order to generate load combinations according to their category (based on the load case category, DL for dead loads, LL for live loads, etc).

The formulae have to be organized in the following order:

  • Mathematical symbols (+,-)
  • The reserved words AND or OR must always be followed by a space.

    Note that the rest of the components of the formulae may or may not be separated by spaces.

  • A factor which may be any real number
  • The name of the desired category. The category should be one of the standard ones (DL, LL, LLr, WIND, SNOW, EARTH, EQ, etc) or one previously defined by the user.
  • Steps 1 – 4 are repeated as required
  • Special commentary lines are also allowed if they start with "//"

Note that the reserved word AND is used to show that each load combination to be generated has to include ALL the load cases that belong to the specified category, while the reserved word OR is used to generate different load combinations for each load case of the specified category

The following example illustrates the procedure

//Example combinations
+AND 1.40DL + AND 1.70LL
+AND 1.05DL + AND 1.28LL + OR 1.40EQ

If there is one dead load case (DL1, category=DL), two live load cases (LL1, LL2, category=LL) and two seismic load cases (EQ1, EQ2, Category=EQ) the following load combinations will be generated:

1.4DL1 + 1.7LL1 + 1.7LL2
1.05DL1 + 1.28LL1 + 1.28LL2 + 1.4EQ1
1.05DL1 + 1.28LL1 + 1.28LL2 + 1.4EQ2

As can be seen, the seismic load cases are not included in the same combination due to the OR designation, while the live loads are always in the same combination due to the AND designation.

In order to generate load combinations for design, service checks or as amplified seismic loads, one of the following lines should be included in the file prior to the formulae in order to have the correct type of combinations:

//To generate combinations to be used with any material:
[COMBOTYPE=COMBO_SERVICE] 
[COMBOTYPE=COMBO_DESIGN]
//To generate combinations to be used with specific materials:
[COMBOTYPE=COMBO_SERVICE_STEEL] [COMBOTYPE=COMBO_DESIGN_STEEL]
[COMBOTYPE=COMBO_AMPLIFIED_SEISMIC]
[COMBOTYPE=COMBO_SERVICE_CONCRETE]
[COMBOTYPE=COMBO_DESIGN_CONCRETE]
[COMBOTYPE=COMBO_SERVICE_WOOD] 
[COMBOTYPE=COMBO_DESIGN_WOOD]
[COMBOTYPE=COMBO_SERVICE_MASONRY]
[COMBOTYPE=COMBO_DESIGN_MASONRY]

When the OK button is pressed the combinations will be generated based on the selected load combination file and the currently available load cases. It is important to note that only the names of the categories can be used in the editor. Load combinations in the template file will be ignored if they contain a load category that is not currently used in the model.

See the example files (path: main program directory /ComboGenerators folder) that come with the program, which have the basic load combinations to consider for the different codes.

In the case of some design modules as retaining wall or continuous beam, the user will have specific files of combinations according to the design code. These files will appear automatically at the moment to call the generator and they will have the extensions .rwg for retaining wall and .cbg for continuous beam.

At the same time the user would select Files of type, choose all files *.*, and have all the available files of combinations of the program at his service, but we remind to the user, it is advisable to use specific combinations corresponding to each module.

Options

Setting Description
Apply notional load cases to gravity load combinations only This option is only enabled when the model has notional load cases defined. When the option is checked, the notional load cases are only combined with the gravity load combinations (load combinations without lateral load cases). If the option is unchecked, then the notional load cases are combined with all possible load combinations defined in the generator file.

Available tools

New formulae file

Creates a new customized load combination generator file.

Delete formulae file

Deletes the selected load combination generator file. Note that the generation files that come with the program (identified with the icon) can not be deleted.

Save template file:

Save a file with the current list of combinations to create a template for future use.

Copy:

Copy the combinations formulae of a template file.

Paste:

Paste the copied formulae to a new template file.