New Steel Column Base Plate Connection Modeling & Design - Eurocode and USA Head Codes

Tekla Structural Designer
Tekla Structural Designer

New Steel Column Base Plate Connection Modeling & Design - Eurocode and USA Head Codes

In Tekla Structural Designer 2021 it is now possible to explicitly model and design steel column Base Plate Connections to the Eurocode and USA Head Codes. The design is carried out and reported fully within the program, with no use of Tekla Connection Designer (TCD), as shown in the picture directly below. For full details of this new feature see the Help topic Column base plate design workflow and this related video.

  • New/ changed operation - base plates will be added (or can be created) in this release for steel columns for all Head Codes and will be listed in the Structure Tree as described below. Other changes are dependent on the Head Code as follows:

    • Eurocode - base plate connections are no longer listed in the Connections tree (after running the Update Connections command/ for existing models in which this has been done). Additionally, for the UK/ Irish Eurocode NA, they can no longer be exported to TCD for design (TCD can still however be used on its own if you wish).

    • United States - base plate connections are no longer listed in the Connections tree (after running the Update Connections command/ for existing models in which this has been done).

    • British Standards - as currently, base plate connections can be added but are not designed directly in Tekla Structural Designer. They can be designed in Tekla Connection Designer (TCD) - either integrated within Tekla Structural Designer or via export. New in this release is that they are listed in both the Structure Tree and the Connections Tree. For more information see the Help topic: Create and design other connections

    • Australia & India - as currently, base plates cannot be checked in Tekla Structural Designer or designed in TCD.

  • Modeling - to enable base plate connections definition, Bolts/ Rods and Weld data is added to the database in this release (see picture below). The bolt/ rod data includes all the required dimensions and design strengths required for design, while the weld data is in terms of the leg length size and, for the USA Head Code, the electrode strength. You can add to and/ or make your own named copies of bolt/ rod sizes and add your own welds data should you need to.

    • Note that base plates and anchor plate Width & Thickness are taken from the existing Plate Dimensions in the Sections Database.
    • Creation - base plate entities are now automatically added on creation of a new steel column when it requires a support. Base plates can also be manually created using the new Add Base Plate button on the Design tab of the ribbon (final button on right of ribbon).

      • Adding base plates works like adding pad bases - you can click on either the column or its support, or window over a selection of multiple columns/ supports. A column which has no support cannot be selected for application.

        • When a pad base (spread footing) also exists at a column support, the base plate connection’s concrete base properties are automatically populated from this.

    • Existing Models - the process and workflow for existing models created in prior releases depends on the scenario, of which there are three:

      • No base plate connections exist - you can add them manually as you need as described above.

      • Base plate connections already exist (the Update Connections process has been run previously) but have not been sized/ designed (using TCD) - when opened in this release, the existing base plate connections are automatically listed in the Structure Tree (see below) and their properties populated. They will no longer be listed in the Connections Window of the Project Workspace (Eurocode and USA Head Codes). The “Autosize” property for them will be off and you can enable it if you wish (recommended - see below) to obtain initial sizing.

      • Sized/ designed base plate connections already exist (Eurocode Head Code models only) - the same process described above occurs and again the base plate “Autosize” property will be off - you can leave it in this state to retain all the sized connection properties. The base plate’s design status will be reset and you can then run a check to update this (see below).

    • Base plates can be selected, moved, copied and deleted - either singly or a selection - just like other entities. Also like other entities, they have a full set of properties which can be accessed for review/ editing both via a dedicated dialog - as shown below - and via the Properties Window for a single or multiple selection.

      • Since they are associated with a column, when selecting a column to move/copy/delete the base plate, as default, will be selected also (just as a column support is) - you can then choose to only move/copy/delete the column by de-selecting the Base Plate from the associated operation dialog.
    • Base plates are also automatically listed in the “Members” group of the Structure Tree, grouped by their column section size. As well as selecting base plates here, it is also possible to run a check design of them via the right-click context menu as shown in the picture below.
    • Autosize - this key property of base plates is enabled by default when they are created. This uses simple geometric rules to produce an initial valid and sensible base plate size and configuration for the column’s section size. When the column's section size is changed - for example by an auto-design - the base plate is adjusted accordingly.

      • The autosized base plate is not guaranteed to be adequate so this should not be confused with auto-design. The engineer will typically need to manually configure the connections - in terms of plate size and thickness, bolt size and layout and weld sizes etc - then run a check to assess if they are adequate.

  • Design Process - as mentioned above, the design process is essentially manual configuration and check-design. Once the column section sizes have been established with autosize enabled, this setting can then be turned off and you can make further manual edits to the base plate properties should you wish to. All base plates can then be checked in a single process via the new “Check Base Plates” button on the Design Ribbon. You can also run design for some or all base plates from the Structure tree as shown in the picture above, as well as for individual base plates via the right-click context menu.

    • Property Sets - note that Property sets can be created for/ from and applied to base plates, just like with other entities in Tekla Structural Designer - so you can use these to rationalize your design for similar/ typical base plate connections.

    • Review View - base plates design results are available with other members via the main Design group of the Review View Ribbon, (not the Connections ribbon group), so you can quickly visually review their design statuses and ratios. The recently added (in 2020 SP6) Review View Entity type filter for Connections can be enabled to focus the view only on base plate design results as shown in the picture below. For more about this feature see Review View - Design Status Enhancements
  • Design Scope & References - these are as follows depending on the Head Code:

    • Eurocode - the design covers all Eurocode Country NA variants and the checks follow the SCI design guide ‘Green Book’ P358 so the scope is:

      • Connection type/ configuration - Simple (i.e. no applied moment) column bases only for I, H or hollow section columns and steel grades S235, S275, S355 & S460 (the default grade for base plate is S355). No eccentricity of the column to the base plate is allowed (ebpz = 0).

      • Design forces*; axial compression and major axis shear (Warning or Beyond scope messages will be issued where these conditions are not met). All load combinations are considered except EQU, GEO, and SEIS combinations from RSA.

      • Design checks - Base plate size (Effective Area Method), Shear and Welds capacity

        • *Note that, unlike for the previous export of column base plates to TCD, the minimum design forces (Design > Settings > Design Forces) are not considered for design within Tekla Structural Designer hence all non-zero forces from analysis are considered.

    • United States - design checks are per AISC DG1, AISC 360 (05, 10 & 16) and ACI 318 (08, 11, 14 & 19) and the scope is:

      • Connection type/ configuration - Simple (i.e. no applied moment) column bases only for W, M or hollow section columns for all steel grades (default grade for base plate is A36-36).

      • Design forces; axial compression only. All load combinations are considered except seismic from RSA.

      • Design checks - Base plate Bearing Strength and Plate thickness.

  • Drawings & Reports:

    • Drawings: Base plates are now included in the following drawings (*anchor plates applicable to Eurocode only):

      • GA drawing - the following information is included; Base Plates, Bolts/Rods, Base plate & bolt/rod details*. Note that the 2x column scaling option applies to base plates also. See picture below for an example (Eurocode).

      • Non-concrete column drawings - both In elevation at the bottom of each column view (minor & major) and In plan (x4 scale in order to clearly show bolt layouts) with the following information included; Base plate, Bolts/Rods, Grout, Welds, Anchor plates*, Base plate, bolt/rod, grout & anchor plate details*. See picture below for an example (Eurocode).

      • New Dedicated Base Plate Drawing - a dedicated Base Plate Member Drawing as been added with the following information shown in elevation & plan where applicable: Base plate, Bolts/Rods, Grout, Welds, Anchor plates*, Concrete base, Base plate, bolt/rod, grout, concrete base & anchor plate details*

      • To control these new items and drawing, new associated layers have been added to Draw > Settings which are on as default in the settings sets for this release. Layer styles and configuration can be adjusted as required.

    • Reports - base plates output can now be included in reports as follows:

      • Model Report - new Base Plates and Base Plate Design Summary report items have been added to Model Report > Chapters and options. The Base Plates item adds the Member Report for all base plates in the model (see below) and the Summary produces a simple condensed table with a single row for each base plate giving the main dimensions, number of bolts, UR and overall design status as shown in the picture below.

      • Member Report - a new Member report has been added for base plates which can be configured and generated in the same manner as other member reports, both individually and included in the model report. The Member Report dialog now includes a “Base plate” member type which has default Design and Design Summary styles as for other member types and these are configured in the same manner. The report includes the new Base plate detail drawing (by default) and an example of the output this gives is shown below.
      • Material List - base plate quantities can also be included in the Material List Report with the following information included (controlled by the Material List > Options > Steel settings); Plates, Bolts and Anchor Plates*.

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