Design Parameters


Design parameters are values that can be assigned to structural members (singly or as part of a selection set).  The specific parameters are dependent on which design code has been chosen.  When a specific design code has been chosen, the associated parameters are then initialized with default values.  The user then applies these parameters to structural members by selecting members individually or as a collection.

Bentley Structural relies on the OpenSTAAD API as a means of read/write of STAAD.Pro STD files.  Part of the OpenSTAAD installation and the basis of values used by the API are data and settings files.  While these files are similar if not exact as those installed by STAAD.Pro, they are not shared.  This fact can lead to confusion in that users think that when they alter settings in STAAD.Pro that the changes will be seen when they export a model from Bentley Structural to STAAD.Pro.  With that said, OpenSTAAD delivers files that define both the available codes and the associated design parameters.  These files are also found within the STAAD.Pro installation.

The available codes that the OpenSTAAD API supports can be found in the “codes.ini” file located in “C:\Program Files\Common Files\Bentley Shared\IEG\OpenSTAADBentley\Data\” (Figure 1).  While it is possible to read this file directly, any access of values within it should be done solely through the OpenSTAAD API. 

Figure 1: Sample of codes.ini settings file.

References within the codes.ini file point to supporting INI files that define the available design parameters and their default values.  For example, when a user chooses the AASHTO, the file referenced would be “SteelAashto.ini” (Figure 2).  These parameters file lists out the finite set of parameters that apply to this code and their default values.  Recall that STAAD.Pro delivers an exact copy of these file in its language folders (“C:\Program Files\SPro2007\STAAD\Language\”).

Figure 2: sample of code specific settings file.

Currently in Bentley Structural, an initial implementation of Design Parameters is such that the code and parameter assignment are disconnected such that the code is set at export time while the design parameters are all displayed and editable during placement and modification.  Regardless of the code that a user chooses, all of the possible design parameters are listed and none of them are initialized.  To resolve this issue and confusion that may occur, it is necessary to better define the workflow so that the two settings (Design Parameters and Code) are linked to one another in the interface.

This document outlines the modification that will be necessary within Bentley Structural to improve the user’s ability to assign design parameters.

Basic Requirements

  1. 1.      User shall be able to assign or not assign a design code.
  2. 2.      The available design codes shall reflect those available in the “codes.ini”.
  3. 3.      The available codes shall be obtained using the OpenSTAAD API.
  4. 4.      The last used design code shall be stored and recalled each time the user opens the export dialog.
  5. 5.      Depending on the design code that the user chose, only the available design parameters shall be accessible.
  6. 6.      All design parameters shall be initialized to the values obtained from the corresponding parameters file.
  7. 7.      The last used design parameters shall be stored and recalled each time the user opens the export dialog.
  8. 8.      A user shall be able to apply the design parameter and there values to any structural member by choosing a structural member or selection set.
  9. 9.      If a user has not chosen to assign a design code, the design parameters should not be written to the STAAD.Pro file regardless if the values exist on the structural member.
  10. 10.   The use of design parameter shall exist only for export to STAAD.Pro from Bentley Structural.
  11. 11.   Only design parameters that exist on structural members shall be written to the STAAD.Pro file is the parameter applies t the code that is chosen at export time.

The existing user interface for the STAAD.Pro within Bentley Structural for export to STAAD.Pro shall include editable fields for each of the possible design parameters (i.e. a union of all possible design parameters).  Each design parameter shall be enabled/disabled depending on the deign code that is chosen.  None of the design parameter fields shall be enabled if the user has not chosen to export the STAAD.Pro file and assign a design code.  At export time a button shall be provided that allows the user to apply the design parameters to individual structural members or selection sets.


Figure 3: STAAD.Pro Export Dialog Design Options Tab.

Figure 4 - With "Specify Design Code" checked, the rest of the controls are enabled

Figure 5 - Use the "Apply” button to assign Design Parameters to members in the model

Note: When running the "Apply" Design Parameters command, it is important to heed the prompts at the lower left of the screen.  When the apply button is pressed, the user is prompted to select the member, once a member is selected, the user is prompted to accept the member, when the member is accepted, the user is prompted a third time to select the next member or reset to complete the command.  It is easy to overlook this third step.  Be sure to use the element info tool to verify the design parameters have been applied.

Figure 6 - First prompt to select a member

Figure 7 - Second prompt to accept the member

Figure 8 - Third prompt to identify next member or reset

Figure 9 - Confirmation that design parameters were successfully assigned

Figure 10 - Use the "Remove" button to remove Design Parameters from members in the model.

Figure 11 - Use the "Match" button to copy Design Parameters from member to another.