Precast member design workflow

Added September 16, 2020 by Tekla User Assistance tekla.documentation@trimble.com

Software version: 
Tekla Structural Designer 2020

Precast member design workflow

Precast member design workflow

The basic workflow for precast design in Tekla Structural Designer is described in the sections below:

Configure precast beam and column design settings

Specific precast beam design settings and precast column design settings that apply to all the beams and columns in the model should be specified prior to running the designs.

These are set on the repective Concrete>Precast pages of the Design Settings dialog.

By ensuring the defaults are set correctly you can avoid having to manually set the values in each Tedds precast calculation as it is run.

You still have control within individual calculations to adjust these settings on a member by member or group basis.

Define and place precast members

To place precast members, simply use the Concrete Column > Precast, or Concrete Beam > Precast commands on the Model tab.

An alternative to this would be to use the Concrete Column > Column, or Concrete Beam > Beam commands and to subsequently change the Fabrication parameter to be Precast.

Configure precast groups

Customizable member groups are created automatically. You can choose whether to utilize them for design purposes via the Design Groups page of the Design Settings dialog.

Using precast member design groups can help speed the overall design process, particularly so in the case of medium to large size models.

  • An envelope of group design forces is passed to a single Tedds calculation.
  • User can manipulate design options, member size, material etc.
  • Any changes are applied to each member in group.
  • Each individual member of group is checked against individual loads without any further user interaction.

The initial precast member design groups can be reviewed from the Groups tab of the Project Workspace - you can move members into new groups as required.

Set the Tedds results output level

You can choose the output level for the Tedds precast calculations in advance by clicking Home > Settings > Report > Tedds Reports

By ensuring this is set correctly beforehand you can avoid having to manually set the level in each Tedds precast calculation as it is run.

The setting applies to all Tedds linked calculations (precast and timber).

Establish design forces by running the analysis

Precast members can only be designed provided a set of analysis results exist. These can be generated from the Analyze ribbon by running Analyze All (Static).

A design force envelope is established, and all critical load combinations are considered in one Tedds calculation.

Provided load combinations have been created, once analysis has been performed the Design using Tekla Tedds options become available.

Design using Tekla Tedds

Note: We recommend that the Tekla Structural Designer model is developed as much as possible prior to considering the design of the precast members. This should ensure that the correct distribution of forces is carried through into the Tekla Tedds calculations.

Design a Selection

To design several precast members or groups in one go:

  1. Select the precast members you want to design.
  2. Right click and select Design using Tekla Tedds> Selection
  3. Design the selected members.
    Note: If grouped design is active, a single grouped design is performed for each group included in the selection using critical design forces established from all members in the group (irrespective of whther ot not they were included in the selection). At the end of the process all members in each designed group are checked, (irrespective of whether or not they were included in the selection).
  4. When changes are made to the model, you can check if the existing sections are still sufficient by by running
  5. Check In Tedds from the Design tab.
    Note: Tedds calculation data is retained from one run of the design to the next unless changes are made in Tekla Structural Designer that force the Tedds calculation data to be re-established. If you want to manually clear the Tedds calculation data from a previous design run you can do so by running Clear Tekla Tedds Data from the right-click context menu.

Design a group

If you have activated concrete member design groups, each group can be designed as follows:

  1. Highlight any member in the group, right click and select Design using Tekla Tedds> Group

    This design gathers the analysis results for all members in the group and collates them in to one design. (In effect assuming that all the worst case loads are happening on one member simultaneously.)

  2. Design the selected member for these loads.

  3. Click Finish.

    If the section size was changed during the design, all members of the group will be updated to the new section. If the reinforcement data was changed this is also copied to all group members.

    Irrespective of whether the section or reinforcement has been changed or not, all members in the group are then automatically checked against only the loads that they see individually. A pass fail status and utilization ratio is calculated accordingly for each one.

  4. In the Review View, review the utilization ratios for all members in the group - if these all indicate an efficient design, the process can stop at this point.
    Note: For columns in particular, the envelope of design forces applied to members of the group can be overly conservative - e.g. if some columns are loaded about one axis, and some loaded about the other, they are all designed as if loaded about both axes.
  5. If a group member has a lower than desired utilization, right click on it and select Design using Tekla Tedds> Member

  6. In the Review View, review the resulting utilizations for the group members - note that some of might now fail.

  7. Using the new utilizations to better inform you choice, add extra groups as necessary and re-allocate the members between the groups.

  8. Run Design using Tekla Tedds> Group for one member in each of the new groups.

  9. Iterate the process, starting from step 5 above.

  10. When changes are made to the model, you can check if the existing designs are still sufficient by by running Check In Tedds from the Design tab. Alternatively you can check groups individually by running Check using Tekla Tedds> Group for one member in each group.
    Note: Tedds calculation data is retained from one run of the design to the next unless changes are made in Tekla Structural Designer that force the Tedds calculation data to be re-established. If you want to manually clear the Tedds calculation data from a previous design run you can do so by running Clear Tekla Tedds Data from the right-click context menu.

Ungrouped Design

If you have elected not to make use of design groups, each member can be designed individually as follows:

  1. Highlight the member, right click and select Design using Tekla Tedds> Member
  2. Design the selected member.
  3. Continue to design additional members in the same way as required.
  4. When changes are made to the model, you can check if the existing sections are still sufficient by by running Check In Tedds from the Design tab.
    Note: Tedds calculation data is retained from one run of the design to the next unless changes are made in Tekla Structural Designer that force the Tedds calculation data to be re-established. If you want to manually clear the Tedds calculation data from a previous design run you can do so by running Clear Tekla Tedds Data from the right-click context menu.

Design model

If you want to design every precast (and timber) member in the model in one go:

  1. In the Project Workspace, click Group tab.

  2. In the tree, right-click Groups.

  3. In the context menu, select Design using Tekla Tedds > Model

    At the end of the process the status and utilization of each member is displayed in a Review View.

Check the design after changes

If changes are made to the model you can run a 'check' design to determine if the existing sections are still sufficient. A check is quicker to perform than a design because the Tedds calculation runs in the background without having to display the Tedds calculation dialog.

The updated utilizations can then be reviewed in a Review View.

Check the whole model

To check all the existing Tedds member designs,

  1. Click Check In Tedds from the Design tab.

    This reruns all the Tedds calculations in the background using the latest analysis results.

Check a selection

To check several members or groups in one go,

  1. Select the members or groups you want to check.

  2. Right click and select Check using Tekla Tedds> Selection

    The Tedds calculations for the selected members or groups run in the background using the latest analysis results.

Check a member

To check a single member,

  1. Highlight the member you want to check.

  2. Right click and select Check using Tekla Tedds> Member

    The Tedds calculations for the selected member runs in the background using the latest analysis results.

    The updated status and utilization are displayed in the member tooltip.

Check a group

To check a member group,

  1. Highlight a member in the group you want to check.

  2. Right click and select Check using Tekla Tedds> Group
    • The Tedds calculations for the selected group run in the background using the group critical design forces.
    • All members in the group are then checked against their individual design forces.

Output the calculations

The Tekla Tedds design results are returned to the Tekla Structural Designer model.

At this stage you can display member design status and utilization ratios from a Review View.

You can also display the design status tabular results.

Detailed Tekla Tedds calculations for precast members do not exist within Tekla Structural Designer itself, instead they are available by exporting to Tekla Tedds.

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