Configuring Load Cases Combinations

 

Combinations represent formulas containing load cases (or other combinations) and calculation coefficients. It is possible to define combinations for finite elements analysis, concrete analysis, steel analysis and timber analysis. The combinations can be user-defined, loaded from files that contain predefined combinations according to standard regulations or automatically generated according to Eurocodes.

The number of combinations defined in the current model is displayed in the Project Browser, in the Settings category.

Combinations in Advance Design

Combinations displayed in the Project Browser

 

How to access the command

 

How to create user-defined combinations

  1. Access the command as described above. The Combinations dialog box appears. All fields that do not contain a combination definition are empty, and in addition, the columns with the number of the load case and the corresponding factor are distinguished by colour.

  1. Click the Add button to add a combination line.

Each row consists of a combination.

Each combination has its own ID number located in the first cell of the row.

  1. Input the calculation coefficient in the Coeff column.

  2. Input the ID of the corresponding load case in the Case column.

Combinations dialog box

Combinations dialog box

 

Note

Each case described in the model (i.e., load case, combination, etc.) has a unique identifier. The IDs of the load cases are viewed in the properties window. Using these identifiers, combinations of load cases and combinations of combinations are defined.

  1. Click OK to apply and close.

How to load combinations files

  1. Access the command as described above. The Combinations dialog box appears.

  1. Click the Loads CBN button.

  2. The Open dialog box is displayed. Each combination file corresponds to a standard. Select the corresponding combination file and click the Open button.

Combinations files

Loading combinations files

Note

If the codes contained in the selected combination file are different from the codes currently assigned to the load cases of the model, a dialog box appears with the message Would you like to update your load cases codes? By selecting Yes, all the existing codes are replaced with the ones contained in the combination file, using the family type criteria.

Confirmation message

Update confirmation message

The combinations are automatically generated: The load cases corresponding to the regulation of the selected file are detected and automatically combined with the coefficients. All possible combinations are generated and displayed in the Combinations dialog box.

Tip

The codes corresponding to each available standard combination file can be viewed. Click View and select the standard combination file to view. Click Open and the file (.cbn) is displayed as a text document along with the code convention of the corresponding standard.

  1. Click OK to apply and close.

 

How to automatically generate combinations according to Eurocodes

  1. Access the command as described above. The Combinations dialog box appears.

  1. Click the Simplified Comb. button. The Combinations options dialog box appears. This dialog box allows the user to automatically generate load cases combinations in conformity with EN 1990:2002, tables A1.1, A1.2 (A,B,C), A1.3 and A1.4. The Ψ coefficients can be adapted to specific situations.

    Combinations option dialog box

Automatic generation of combinations according to Eurocodes

 

 

Project situation

ULS: defines the ultimate limit state combinations: EQU, STR/GEO.

SLS: defines the service limit state combinations: Characteristic, Frequent, Quasi-permanent.

Predominant action: when enabled, it defines the corresponding load case as dominant variable.

Dead loads, Live loads, Snow loads, Wind loads and Temperature loads: drop-down lists define the coefficients values in conformity with Eurocodes.

Using the User-defined option, it is possible to define custom factor values.

: restores the default values.

: generates the load cases combinations.

 

  1. Enable the ultimate limit state combinations set and service limit state combinations set.

  1. Enable the predominant actions by clicking the corresponding icon.

  2. Set the options considering the location of the construction. Select the User-defined option to input custom coefficient values.

  3. Click Generate. The corresponding combinations are displayed in the Combinations dialog box. In case of generating a lot of combinations, now the progress bar is shown and there is a possibility to abort the operation with pressing the End key on the keyboard.

How to reinitialize the default values

To return to the default values, click .

 

How to define concomitance between load cases

In Advance Design it is possible to define the concomitance between load cases when generating combinations.

  1. Access the command as described above. The Combinations dialog box appears.

  1. Click the Detailed Comb. button. A dialog box appears with the message Would you like to update your load cases codes? By selecting Yes, all the existing load case codes are updated.

  2. A dialog box appears with the message Would you like to apply all the concomitance rules set by default? By selecting Yes, the concomitance matrix will be reinitialized according with these rules.

  3. The Concomitance between load cases dialog box appears. The table contains all the load cases generated in the project, listed on rows and columns. Each cell of the matrix defines the concomitance status between two loads (the load from the row and the load from the column) by a certain value. Define the concomitance status between the loads:

    • 0 - Exclusive: when one of the load cases belongs to a combination, the second one must be excluded.

    • 1 - Possible: the loads can belong to the same combination.

    • 2 - Forced: both loads must belong to the same combination.

    Concomitance between load cases dialog box      

Concomitance between load cases

 

Tips

  1. A color is assigned for each situation. When changing the concomitance status, the field color changes accordingly.

  2. You can define the type of the combinations sets to be generated by the concomitance matrix by clicking the Parameters button. The General parameters dialog box appears.

  3. It is possible to export the content of the table to Excel application, by clicking the Export Excel button.

  4. The concomitance table can be printed by clicking the Print button.

  5. You can define the concomitance rules between load cases or between load families by clicking the Rules button. The Concomitance rules dialog box appears.

  6. The default values can be restored by clicking the Reset button.

  1. Click Generate. The corresponding combinations are displayed in the Combinations dialog box.

  2. Click OK to apply and close.

 

How to define loads combinations for the concrete design calculation

The concrete design expert calculates the concrete elements by serviceability limit states (ELS) and ultimate limit states (ELU and ELUA). The combinations of load cases used in the reinforced concrete calculation are defined using the Combinations dialog box.

The combinations that were defined (by manual input or by loading a standard combinations file) within the Combinations tab are automatically recognized and loaded in the Concrete tab of this dialog box. To configure the combinations used in the reinforced concrete analysis:

  1. Access the command. The Combinations dialog box appears.

  2. On the Combinations tab, define the load combinations:

or

  1. Access the Concrete tab. The combinations defined according to the concrete regulation codes on the Combinations tab are automatically recognized and loaded on the Concrete tab.

Concrete combinations

Defining loads combinations for the concrete design calculation

 

 

Concrete combinations list: Displays all the combinations created according to the selected concrete standards, that will be used during the concrete calculation. The Code column displays the code of the corresponding combination. Type allows the definition of the combination limit state and Duration allows the definition of the action period (for example, the actions of the combinations that include seism cases are on a short term).

Modify list: Opens the Combinations - selection dialog box which allows the selection of the load combinations for the concrete design calculation.

Display by type: Filters the content of the combinations list according to their type (state).

Display by duration: Filters the content of the combinations list according to duration: under 24h, 1 to 24h or over 24h.

  1. For each combination, it is possible to define the limit state type and the duration of the load application, using the drop-down list options corresponding to each column.

Tip

The displayed combinations are filtered by type or by duration of loads application using the corresponding drop-down lists located at the bottom-right of the dialog box.

  1. To define which combinations are used during the calculation, click Modify list to add / remove combinations. The Combinations selection dialog box appears. The table on the right contains the selected combinations, which are considered during the analysis. By default, all the available combinations are selected. The table on the left contains the combinations that are not used during the analysis. (The list is empty when all combinations are selected.)

  1. Click OK to apply and close the combinations selection dialog box.

  1. Click OK to validate and close the Combinations dialog box.

How to define loads combinations for the steel design calculation

The combinations defined according to the steel regulation codes (by manual input or by loading a standard combinations file) on the Combinations tab are automatically recognized and loaded on the Steel tab of the Combinations dialog box.

To configure the combinations used in the calculation of deflections, shapes and fire verification of steel elements:

  1. Access the command. The Combinations dialog box appears.

  1. On the Combinations tab, define the load combinations:

or

  1. Access the Steel tab. The combinations defined according to the steel regulation codes on the Combinations tab are automatically recognized and loaded on the Steel tab for the deflections, profiles and fire verifications.

Steel combinations

Defining loads combinations for the steel design calculation

 

 

Steel verification drop-down list: Defines the steel verification type: Deflections, Profiles or Fire (available for EC3). For each verification there are available certain combinations.

Steel combinations list: Displays all the combinations created according to the selected steel standards, that are used during the steel calculation. The Code column displays the code of the corresponding combination. It is possible to define type, strength and safety factors.

Modify list: Opens the Combinations - selection dialog box which allows the selection of the load combinations for the steel design calculation.

Display by type: Filters the content of the combinations list according to their type.

  1. From the drop-down list located at the top-left of the dialog box, select the steel verification type (i.e., deflections, profiles or fire) to view the corresponding combinations.

  2. Define the parameters of each combination specific to the selected component (i.e., deflections, profiles and fire verification), using the options in the available columns (i.e., type, safety factors, strength factors, stability factors, etc.).

Defining the parameters

Defining parameters

 

Tip

Filter the displayed combinations by the criteria available in the bottom-right drop-down list.

  1. To define which combinations are used during the calculation, click Modify list to add / remove combinations. The Combinations selection dialog box appears. The table on the right contains the selected combinations, which are considered during the analysis. By default, all the available combinations are selected. The table on the left contains the combinations that are not used during the analysis. (The list is empty when all combinations are selected.)

  1. Click OK to apply and close the combinations selection dialog box.

  2. Click OK to validate and close the Combinations dialog box.

How to define loads combinations for the timber design calculation

The combinations defined according to the timber regulation codes (by manual input or by loading a standard combinations file) on the Combinations tab are automatically recognized and loaded on the Timber tab of the Combinations dialog box. To configure the combinations used in the timber analysis:

  1. Access the command. The Combinations dialog box appears.

  1. On the Combinations tab, define the load combinations:

or

  1. Access the Timber tab. The combinations defined according to the timber regulation codes on the Combinations tab are automatically recognized and loaded on the Timber tab for deflections, profiles and fire verifications.

Timber combinations

Defining loads combinations for the timber design calculation

 

Timber verification drop-down list: Defines the timber verification type: Deflections, Profiles or Fire. For each verification there are available certain combinations.

Timber combinations list: Displays all the combinations created according to the selected timber standards, that will be used during the timber calculation. The Code column displays the code of the corresponding combination. Type and Duration columns allow the definition of the combination type and duration.

Modify list: Opens the Combinations - selection dialog box which allows the selection of the load combinations for the timber calculation.

Display by type: Filters the table content according to the combination type: ULS, SLS, AULS.

Display by duration: Filters the table content according to the duration.

  1. From the drop-down list located at the top-left of the dialog box, select the timber verification type (i.e., deflections, profiles or fire) to view the corresponding combinations.

  2. Define the parameters of each combination specific to the selected component, using the options in the available columns (i.e., code, type, duration).

Defining parameters

 

Tip

It is possible to filter the displayed combinations by type and/or duration, using the corresponding drop-down lists at the bottom-right of the dialog box.

  1. To define which combinations are used during the calculation, click Modify list to add / remove combinations. The Combinations selection dialog box appears. The table on the right contains the selected combinations, which are considered during the analysis. By default, all the available combinations are selected. The table on the left contains the combinations that are not used during the analysis. (The list is empty when all combinations are selected.)

  1. Click OK to apply and close the combinations selection dialog box.

  2. Click OK to validate and close the Combinations dialog box.

How to select combinations

Access the Combinations dialog box.

How to define the list of combinations used in specialized analyses

The list of combinations used in the concrete, steel and timber analysis can be modified, in order to define which combinations are used during the calculation.

  1. In the corresponding analysis tab, click Modify list to add / remove combinations. The Combinations selection dialog box appears. The table on the right contains the selected combinations, which are considered during the analysis. By default, all the available combinations are selected. The table on the left contains the combinations that are not used during the analysis. (The list is empty when all combinations are selected.)

To select combinations:

Tips

To select non consecutive items, separate the identifiers with a space: 1 5 10.

To select a range of consecutive items, use the dash: 1-10.

The selection methods described above can be combined: by entering 1 2 102-104, the selected cases are 1, 2, 102, 103 and 104.

  1. To move the selected combinations form a list to another, click the corresponding arrow button.

  1. Click OK to apply and close.

How to delete combinations

Exchange of load combination definitions with Excel

In Advance Design, it is possible to easily manage load combination definitions by using Excel. On the dialog window used for defining load combinations the Import and Export buttons are available:

 Exhange of load combination definitions

Link with Excel

 

The Export button exports the definitions of all load combinations existing in the project to a new Microsoft Excel spreadsheet. For this, a dedicated xlsx file is created on the path selected by the user.

Export option

Load combinations definitions exported to Excel

 

The Import button reads the definitions of load combinations from the selected spreadsheet and adds them to the existing definitions on the current project. In case when in the project there are already combinations with the same ID number, then the ID number of the imported combinations is modified. If the definition of a combination in the Excel file is incorrect (e.g. it contains case numbers that do not exist in the model) then such a combination is omitted during import, along with an appropriate warning.

 

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