Enhanced Sway/ Drift/ Wind Drift & Seismic Drift Check Control and Reporting - All Head Codes

Added July 13, 2021 by Tekla User Assistance tekla.documentation@trimble.com

Software version: 
Tekla Structural Designer 2021

Enhanced Sway/ Drift/ Wind Drift & Seismic Drift Check Control and Reporting - All Head Codes

Enhanced Sway/ Drift/ Wind Drift & Seismic Drift Check Control and Reporting - All Head Codes

The control settings and reporting for the Sway/ Drift/ Wind & Seismic Drift Checks have been thoroughly updated and enhanced for this release in line with customer feedback. All these checks assess the relative lateral deflections of successive levels - resulting from lateral loads of various kinds - and so their results and reporting requirements are similar. Tekla Structural Designer has always performed these checks very thoroughly in line with the design code intent by assessing the deflections of all columns and walls (where not specifically excluded) on a stack/panel basis and also reported the results on this basis. While this does follow the code requirements, they generally describe these checks in terms of levels - rather than stacks/panels - and with one check per level rather than many. Hence the sway results as previously presented were potentially less in line with the engineer’s expectations, over-complex and difficult to efficiently assess. This is addressed in this release as follows:

  • Common Changes - all the Sway/ Drift/ Wind Drift & Seismic Drift check results in all reporting locations are now presented in terms of levels rather than column/ wall stacks/ panels.

    • Level Check Control - there is now a single control in Level Properties “Check for drift” as shown below. This is only listed for levels set as floors and when enabled removes the level from the check reporting for all sway/ drift checks (although the checks are still performed for stacks/ panels above/ below it).


      Note: Because the above “Check for drift” setting can sometimes be misinterpreted as a control that switches checks on and off, if you are running 2021 SP2 or later, to clarify its purpose you will find it has been renamed "Reporting Level" as shown below. For more details see: 2021 SP2: Embodied carbon - New reporting for piles and distribution by level



    • Status Window Sway/ Drift Results - the check Warning and Fails status for these results in the Design Status group are now grouped by Level as shown below right - each level group lists the individual columns/ walls with the status for that level. This can indicate immediately the level(s) where sway/ drift is a problem while the previous result display did not.

  • Accessing Sway/Drift Review Views - the Review Data Table and Show/Alter State Views can now be opened directly from the Status Window as shown in the picture below - just right-click over a Warning/ Fail message in the sway/ drift results tree and select to open either its associated Review Data Table or Show/Alter View from the context menu. The Show/Alter State Views automatically open with the Review Mode activated.

  • Sway/ Drift Review Data Tables - these are similarly improved as shown in the pictures below comparing the 2021 (Eurocode) Sway results to those in previous releases. The results are now reported by level, producing a more compact results table where problematic levels are immediately apparent. While the picture below shows the (Eurocode) Sway results table, all Sway/ Drift, Wind Drift and Seismic tables for all Head Codes are similarly improved.

    • Similar to the Material List and Embodied Carbon tables, the sway/ drift result tables now have two levels - Summary Only and Detailed - controlled by the “Summary Only” toggle button directly below the table drop list at the top right of the Review Data ribbon tab. The Summary Only option (default) lists only the critical columns/ walls stacks/ panels for each level. Set the “Summary Only” toggle button to see results for all columns/ walls stacks/ panels (sorted by level).

    • In a similar manner to the Material List and Embodied Carbon tables, you can also now double-click on a row in the sway/ drift review tables to locate the associated column/ wall stack/ panel in the model - doing this will automatically switch to the 3D Structure view, select and arrow it.

    • Note that results for both columns and walls can now be viewed simultaneously in a single table where previously they could only be viewed separately.






  • Show/Alter State Views - the Review Mode view for these is improved to give results on an individual stack/ panel basis (for all Combinations), again giving a much clearer indication of where sway/ drift problems are located as shown in the picture below. Where previously the entire column/ wall was assigned the critical status/ color, now each stack/ panel is assigned its own individual status/ color. This is controlled by the “Entire Member” Mode option which is enabled by default. You can check this off to see a view similar to previous versions with the entire column/ wall having the status/ color of the critical stack/ panel. While the picture below shows an example (Eurocode) Sway results view, the views for all Sway/ Drift, Wind Drift and Seismic results for all Head Codes are similarly improved.

    • The legend is also expanded with more statuses including “Not Required” for stacks/ panels for which the sway/ drift check has been turned off.

    • The following additional improvements are made for the Toggle and Set On/ Off modes used to set the sway/ drift check on/off for selected members. Again this applies to all sway/ drift checks and Head Codes.

      • These modes can now be used for walls where previously only columns were available.

      • An Entity Type filter has been added to specify which entities can be selected for the current operation with options of; All, Columns, Walls.






  • Wind Drift - some specific improvements are made to the settings and checks for Wind drift, again in line with customer feedback.

    • Wind Drift Limit - a new Wind drift ratio limit value control is added in Design Settings > Sway & Drift Checks as shown below. This allows the engineer to set the drift limit for the entire model in a single step, where previously this was set on an individual column/ wall and span/ stack basis.




  • The column/ wall properties are changed accordingly also - in place of the previous limit value, there is now an “Override…” checkbox. This is off by default, in which case the value set in Design Settings is used. When enabled you can enter your own limit value - again on an individual column/ wall and span/ stack basis.




  • The Review View > Show/Alter State Wind Drift controls for the “Set On” mode are also enhanced accordingly; options are added to enable the override option and set the limit value for selected members. The view color-coding and legend update to reflect this operation for the current drift limit value to show; members with the current override applied, those with other override values and the default (set in Design options), as shown in the picture below.

  • Resultant Wind Drift - to cater for wind loads/ resulting displacements being at some intermediate angle w.r.t. the building directions, a new Design setting has also been added to set the Wind Drift check to consider Resultant (i.e. square root of sum squared) drift values, rather than values for each building direction separately as previously, as also shown in the picture above right. This is on by default and, in conjunction with the enhancement detailed above, produces a much more immediately useful and compact results table, as illustrated in the picture below. Simply set the new setting off should you wish to see check results for each direction separately.

    • Note that you can also now select individual load combinations to review their results via the combinations drop list at the bottom right of the program window as shown below. By default this is set to “All Combinations”, giving the critical results considering all combinations. In recent previous releases this was the default setting and could not be changed to view individual combination results.

    • The check details report the derivation of the resultant deflection and drift values when this setting is enabled.





  • Reports - all the associated report items for the sway/ drift checks have also been updated accordingly to encompass the improvements detailed above. It is thus now possible to obtain much more succinct and clear sway/ drift reports.

    • The configuration settings for the Wind Drift item are also changed to reflect the enhancements as shown below - the options for reporting only critical stack/ combination are removed as no longer required.



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