From ETABS to Tekla Structural Designer

This article explains how to send a ETABS model to Tekla Structural Designer, using BIM Expert.

1. Preparation in ETABS

Analysis in ETABS is not required.

2. Send the ETABS model to Tekla Structural Designer

2.1 From ETABS to BIM Expert

In the Model tab, select ‘Import’. Next, choose the source software manufacturer, namely ‘Computer and Structures, Inc’ (CSI) . Click  to continue.

Choose ‘ETABS’.

Alternatively, models can be sent to BIM Expert directly within ETABS (Tools > BIM Expert), but you first need to add BIM Expert as a plug-in to ETABS.

2.2.1 Settings

Select your ETABS version, and were the model is coming from:

• A running instance – that means, the model is currently open in ETABS
• An existing model – click ‘Browse… ‘ to open your file browser, go to the model location and select the model (an .edb file)

On top of the geometry conversion, you can also consider loads and results in points, bars & plates.  Bar results are the most used and relevant ones, so only considering the bar results is enough. Plate results can be huge amount of data, that is currently not used any further.

Next, the ETABS material and sections must be mapped with BIM Expert ‘s materials and section. BIM Expert will try to find as many automatic mapping matches as possible. In case all sections and materials find a match, you will not see any dialogs for mapping.

2.2.2 Material mapping

Database materials such as steel (e.g. S235, ASTM-Grades), concrete (e.g. C25/30, M50) and timber (e.g. C24, D50, GL28c) are mapped automatically. In some cases, the match is not automatically found, because the name differs (S355-link instead of S355). In that case, you can select the correct material from the database.

Tip: When searching an item in the database, type the first letters of the name to find it more quickly.

2.1.3 Section mapping

Database sections (such as I, H, UB, UC, W, C, U, O, ☐ and L sections) are mapped automatically. In some cases, the match is not automatically found, because the name differs  (e.g. name is HEB300 – S235 instead of HEB300). In that case, you can select the correct cross-section from the database.
Tip: When searching an item in the database, type the first letters of the name to find it more quickly.

Parametric sections (e.g. rectangles, circle, trapezium, …) are not in the database. They should always be added as new.

2.1.4 Loads mapping

If you opted to consider the loads during export, the ETABS load combinations need to be categorized. Each valid ETABS combination must be categorized into Eurocode or American combinations. Use the checkbox ‘Use categories according to Limit States’ to switch between European and American combination categories.

Depending on the design code, you must map each combination with either

• Eurocode Limit States
  • ULS – Ultimate Limit State Combinations: Fundamental (FC), Seismic (SC), Fire (FI) or Accidental (AC)
  • SLS – Serviceability Limit State Combinations: Rare (RC), Frequent (FC) or Quasi-Permanent (QP)
  • Custom
• Armerican
  • Strength
  • Service
  • Custom

On hoovering with the mouse over the combination’s name, you can see the build up of the combination (e.g. 1.35 DL + 1.50 LL).

Use SHIFT and CTRL commands as in Windows to select one or multiple items. For example, to select all, use ‘CTRL+A’ and then, select the “+” button in the corresponding column.

Envelope combinations and dynamic seismic combinations are cannot be matched, as this is not supported by BIM Expert. These types of combinations are considered non-valid and will be greyed out. Static seismic combinations can be mapped.

Remark: If you cancel that load mapping dialog, combinations are neglected and the conversion proceeds.

2.1.5 Reporting

In case of severe incidences, you get a report of the incidences. It usually concerns load cases or element behavior that are not supported by BIM Expert. Click ‘Continue’ to proceed anyway.

The model is now in BIM Expert.

2.2 From BIM Expert to Tekla Structural Designer

In the Model tab, select ‘Export’. Next, choose the destination, namely “CXL’. Click  to continue.

Next, you will be prompted to save the file

2.2.1 Material & section mapping

Most common materials and sections are mapped according to the TSD neutral file mapping conventions. If there is no match found, a default section and material will be applied. You can specify these defaults in ‘File > Settings > CXL’

3. Final steps in Tekla Structural Designer

1. On the BIM Integration tab, click Structural BIM Import.

   The BIM Integration wizard opens.

2. Use the […] button to browse and select the appropriate CXL file.

   The remainder of the fields are populated with the settings read directly from the file.

3. Click Next to continue.

   The Import Options page shows the settings related to the file, it will indicate if this is a first time import or an update, and allows the user to choose Metric or Imperial for the units, a design code and the default level type. The level type can later be adjusted in the construction levels dialog if required.

4. Click Next to continue.

   The Relocate Import Model page allows for models to be moved to around the datum position in Tekla Structural Designer from a real world co-ordinate. The extent of the model can be seen from the information displayed on the right hand side of the dialog.

5. Click Next to continue.

   The Integration Filter will be displayed. The five options shown here allow you to verify if grids, levels etc. are to be imported. Please note that the settings held in the Delete Existing… and four Update… columns should not be used when performing a First Time Import and are only used when synchronizing changes into an existing Tekla Structural Designer model.

6. Click Next to continue.

   Mapping of materials to recognised grades will be shown now. Here you can view the different materials recognised in the incoming CXL file and the options to alter materials with a more preferred grade.

7. Click Next to continue (if available).

   Following on from Material mapping, the dialog for Decking mapping will be shown (if applicable). Again this allows users to view the decking types being imported and have the option of overwriting the details if required.

8. Click Finish

   After the file has completed processing, the model will be displayed within the Structural 3D view and you can then proceed with validation of the structure before applying any analytical information.