Tekla Structural Designer 2018 release notes

Tekla Structural Designer
Tekla Structural Designer
British Standard
Not environment-specific


With the release of Tekla Tedds 2018, Tedds Engineering Library (March 2018) update, the new Tekla Structural Designer > Tekla Tedds Timber Design Calculation link can be used to design timber members in a Tekla Structural Designer model (for the Eurocode headcode). For how to use the link please see the Tekla Structural Designer Tekla User Assistance video Timber design using the Design using Tekla Tedds Export feature.

This release will upgrade your Tekla Structural Designer installation to version number and should be installed to ensure optimum function of the program.  It includes a number of significant new features together with several enhancements and issue resolutions as detailed below. 

If you are upgrading from a version earlier than Tekla Structural Designer 2017i SP4 (version you can find details of enhancements and fixes included in all previous releases in Tekla User Assistance (TUA) and Tekla Downloads via the links below:

Licensing & Installation

  • Licensing:
    • New Licenses - Tekla Structural Designer 2018 will require the activation of a new license.  You should already be in possession of your Product Activation Key (PAK) as these are usually distributed prior to the software release.  Please contact your local Service Department now if you do not have your PAK.  To minimise any down time we advise that your PAK is activated before installing Tekla Structural Designer 2018. 
    • Server Licensing - for Server licensing there is a new version of the Tekla License Service.  Please note that this must be installed on your license server to ensure licensing functions fully and correctly.  Just follow our simple online Setup Guide to ensure your installation and licensing goes smoothly.
  • Installation:
    • 32-bit - As previously notified Tekla Structural Designer 2017i was the last release that included a 32-bit version.  Hence only 64-bit operating systems are now supported on which the 64-bit version of the program will be automatically installed.  Please see System Requirements for more information.
    • Previous Versions and file compatibility - to aid with transition, this release will install alongside existing versions and does not overwrite them.  Files from all previous versions can be opened in Tekla Structural Designer 2018 however note that, once saved, they cannot then be opened in an older version.  If you wish to retain this option we therefore recommend using the File > Save As… option to save a new version of the file in Tekla Structural Designer 2018 and retain the original.
    • Section Databases - in this release Section databases include new and updated properties required for new features, enhancements and fixes.   A message that a new database is available will be displayed in the Process Window as shown below when this release is installed and run for the first time. 

      TSD 2018 - Update materials.png
    • Your local section databases should then be upgraded as follows;
      • Open “Materials” from the Home Ribbon, select the “Sections” page in the list of options, click the “Upgrade” button, then click this button again in the subsequent “Upgrade Database” dialog.  Repeat this process for the other databases (Material, Reinforcement...etc ) to ensure all your databases are up to date.
      • For the US Head Code with US Customary units, the section database and models including plated sections should also be updated as follows:
        • Go to Home > Materials > Sections > Plate Dimensions and click the (new) “Reset” button on both the “Widths” and “Thicknesses” pages to correct the stored plate dimension value precision. (For more information on this requirement please see Product Bulletin PBTSD-1803-2).
          • Note that this will remove any user-added plate dimensions which will then need to be re-added.

          TSD 2018 - Update Plates.png
        • To correct existing user-added plated sections go to Home > Materials > Sections > Manage Sections and Edit each one, re-selecting the reset dimension entry box(s) which will now appear blank.
          • Note that new sections with the same plate dimensions can be added first and the properties compared for the engineer to decide if this is necessary.
        • For existing models using plated sections edited as described above, the sections should then be re-selected for all members using them.

Issues with Associated Bulletins

  • Steel Members - Plated Sections - where US customary units were used, plate dimensions were stored with insufficient precision resulting in a loss of accuracy for plated section properties.  We would note that in general the issue affected principally analysis, as design for plated sections was not carried out in previous releases for countries/codes for which US units are customary.  Additionally, since plated sections are most commonly large and section properties would tend to be underestimated, any error would most likely be minor and conservative.  For more information please see Product Bulletin PBTSD-1803-2 (54288).
    • This issue is addressed in this release for new plate dimensions and plated sections - plate dimensions are now stored with increased precision improving the accuracy of plated section properties.
    • Please see the Installation section above for what to do for existing plate dimensions, plated sections and models using these.
  • Steel Design - Braces - BS Head Code - for braces subject to tension using double-angle sections, the tension capacity check used the gross area Ag of the brace, rather than the net area Ae , potentially producing an unconservative design result.  This issue relates only to  Tekla Structural Designer 2017i (version released in Sept 2017) and subsequent releases.  For more information please see Product Bulletin PBTSD-1803-1 (54881).
    • The issue is fixed in this version.

New Features

FLAT SLAB DESIGN - New!  Slab Deflection Analysis

A completely new feature is now added for the rapid and rigorous assessment of slab deflections accounting for the slab reinforcement and the effects of cracking, creep and shrinkage.   A new Help Topic guides the engineer on the use of the new feature - see Help > Engineer’s Handbooks > Slab Deflection Handbook > Slab Deflection Example (Eurocode)/ (ACI) > Rigorous Approach…  Also see the following videos on the new feature in TUA

  • Rigorous Slab Deflection Eurocode
  • Rigorous Slab Deflection US Code

    TSD 2018 SDA.png
  • The Head Codes supported for this new feature in this release are Eurocode (All Countries and NAs) and US.
    • For the Eurocode, the method follows guidance in EC3 and the Concrete Society Guide TR58 “Deflections in concrete slabs and beams”.
    • For the US code, the engineer can follow either a simplified route for basic ACI 318 compliance or take on some of the more detailed guidance in ACI 435.
  • A new dedicated Slab Deflection Ribbon Tab is added to manage the new analysis and results.  This features new controls to define specific slab Event Sequences - such as when the slab is struck, when certain loading is applied/removed etc - and their associated parameters.

    • Event Sequences can contain any number of loadcases, each with a user-defined percentage of load applied for the sub model and from chasedown analysis.
    • Once events are are defined, a single analysis process is run which can be set for; the Current Level (when in a level view), Selected Sub Models or the entire model.  
    • Following analysis, a new View Type “Slab Deflection View” enables comprehensive assessment of deflection results in detail, as well as overall Slab Deflection Pass/Fail Statuses and Utilisation Ratios.
  • A new form of nonlinear, iterative analysis underpins the feature termed Iterative Cracked Section Analysis:
    • During analysis, this automatically calculates unique properties for every shell of the slab 2D element mesh based on; the input parameters, the amount of reinforcement in the slab and the bending moment induced.  For every shell:
      • For each direction an Effective Reinforcement is determined.
      • For each Event (for each direction) the cracked/uncracked status is determined, the extent of cracking is assessed and a unique effective stiffness is established and assigned.
    • For each event, the final solution produces; Total, Differential and Instantaneous deflections.  Any of these can be selected for review via graphical contour diagrams and as governing criteria for deflection checks.
    • In addition to deflections, for every shell the engineer can also graphically assess, via colour coded diagrams; Extent of Cracking, Relative Stiffness and Effective Reinforcement values.
    • While the analysis involves a potentially huge amount of detailed and intensive computation, convergence of the solution is generally rapid and we believe the analysis speed is class-leading.
  • With the primary focus on productivity and ease-of-use, while the underlying analysis is rigorous and complex, the feature is straightforward to use:
    • Check Lines - rather than producing as a final result only deflection contour diagrams, a unique feature enables the graphical definition of automated deflection Check Lines  of any number and in any location.  Any number of dedicated slab Deflection Checks related to the Events can be defined for the lines in the Slab Deflection Check Catalogue, each with their own deflection criteria and limits.  The Check Lines are automatically processed and checked as soon as they are created and analysis results are available.  They produce a clear pass/fail status for each line and slab panel they intersect and can be individually interrogated in detail.  After any changes and re-analysis the Check Lines are automatically re-checked.  Concise results for each line including overall status and key values can be included in a Report.

      TSD 2018 SDA check line.png
    • This feature, in conjunction with the rapid analysis, allows value-engineering and assessment of alternative schemes in economic timeframes, all in a single model and interface.
    • Full control is available over all parameters which govern the analysis:
      • Two new Deflection parameters are added to slab properties; Cement Class and Restraint Type.
      • Further analysis parameters, such an Allowance for shrinkage factor (default value = 25%), are found via Slab Deflection Tab > Options.  These settings are also listed in Home > Settings where they can be set for new models.
      • While generally sensible default values are set for all parameters, the engineer is encouraged to review and edit them as appropropriate for their unique building, circumstances and requirements.
  • Considerable effort has also been expended to make the process transparent to the engineer, rather than a ‘black box’:
    • An automated Composite Modulus Report is available from the right-click context menu > “Export Eff. Modulus Report to Excel”.  This can be produced for a selected slab item or all items and lists detailed composite modulus calculation values for each Event.
    • Extensive, detailed intermediate values are listed for each individual shell in the cursor tooltip when viewing all the following graphical shell result diagrams; Extent of Cracking, Relative Stiffness and Effective Reinforcement values.

INTEGRATION -  New!  Tekla Portal Frame Designer and Tekla Connection Designer

Tekla Portal Frame Designer (TPFD) and Tekla Connection Designer (TCD) replace the previous Fastrak versions - their scope and functionality being essentially unchanged.  New links in Tekla Structural Designer link to these enabling integrated, dedicated Portal Frame and Connection design.

Portal Frames

  • The Head Codes supported in this release are Eurocode (UK and Irish NA’s only) and BS.
  • Portal Frame objects defined in Tekla Structural Designer can now be exported to TPFD - either individually via right-click “Export to Portal Frame Designer” or multiple frames by selecting then clicking Home > TPFD Export.
  • All Portal Frame geometry and loading is defined in Tekla Structural Designer and exported to TPFD.  Member restraints defined by connecting members, such as rails and purlins, are also exported.
  • Once the frame is designed in TPFD, changes in section size for stanchions and rafters can be returned to the Tekla Structural Designer model.
  • Note that the TPFD file is not saved in Tekla Structural Designer nor are Design Status or Details.  Hence Design Report output is made from TPFD and the file can be saved in this program if it is required for future reference.
  • A number of improvements and enhancements have also been made the Portal Frame definition dialog in Tekla Structural Designer.


  • The Head Codes supported in this release are; BS, Eurocode (UK and Irish NA’s only) and US (Base Plate Connections only).
  • A new Connections Workspace is added to manage connections.  Choosing “Update Connections” from this (via a right-click) runs an initial automatic creation process (using hard-coded defaults for plate and bolt sizes etc) which populates the workspace with a list of all created connections.
    • Connections are listed by Type and Reference e.g. Base Plate Connections, Beam to Beam Moment Connections, Beam to Column Moment Connections.  Connection icons are also added to the building model itself identifying their location.

      TSD 2018 Connections.png
  • The following connection types can currently be defined; Column Base Plates, Beam-to-Beam Moment Connections and Beam-to-Column Moment Connections.
  • Following design of the building, connection geometry & forces are automatically set for each connection.  Connections can then be fully edited and designed directly in Tekla Structural Designer in a dedicated dialog opened by right-clicking the connection either in the Workspace or via its icon in the Scene .  All connection details and design statuses are saved in the Tekla Structural Designer model file.
    • Base plate size, connection status and utilization ratio are returned to the Tekla Structural Designer model, however any changes to Column and Beam size/ Grade must be manually updated and analysis updated to reflect these.
  • Although it is possible to design portal frame connections in Tekla Structural Designer, it should be noted that the design forces used for connection design within Tekla Structural Designer would be those from Tekla Structural Designer (elastic) analysis, not those from TPFD (elastic-plastic) analysis.  Therefore it is advised that connections within portal frames - i.e. Column Base, Eaves moment and Apex moment connections - should be derived from TPFD and not from Tekla Structural Designer .
  • Single and multiple connections can also be exported to an external TCD instance/ file; either singly via the right-click context menu, or multiple connections by selecting then clicking Home > TCD Export.  When the connection is designed externally in this manner design details can be returned to Tekla Structural Designer via to menu command Connection  > Return connection to TSD.

CONCRETE DESIGN -  New!  Design to Australian Concrete Codes.

For the Australian Head Code, Reinforced Concrete (RC) members are now designed to AS 3600-2009 (incorporating Amendment Nos 1 and 2) and AS/NZS 4671-2001.  The new design capability applies to all of; Beams, Columns, Walls and Slabs and to auto-design for reinforcement selection, as well as checking.   In addition GA and Detail Drawings for all members feature the calculation and display of lap lengths and anchorage lengths to the code provisions.

TSD 2018 AUS Concrete design.png

Beams Design Features

  • Design for major axis bending and shear and torsion for auto generated gravity and pattern load combinations.
  • Deflection check as per AS 3600-2009, cl. 8.5.3, 8.5.4.
  • Can be set to use either the simplified method or the span to depth ratio check.
  • Both methods calculate and check short term and long term deflection.
  • Crack control check as per AS 3600-2009, cl. 8.6.1.
  • The service moment is calculated and checked against the limiting steel bar stress and the following bar diameter and spacing limits:
  • Maximum diameter of bar as per Table 8.6.1 (A) of AS 3600-2009
  • Maximum Centre to Centre spacing as per Table 8.6.1 (B) of AS 3600-2009

Column Design Features

  • Check and design for all auto generated gravity and lateral load combinations for axial loading + biaxial bending and shear.
  • Caters for both braced and unbraced (short & slender) conditions.
  • Confinement to the core if required is checked as per AS 3600-2009, cl. 10.7.3.
  • For both check and design, spacing of fitments is determined to satisfy the confinement pressure.

Wall Design Features

  • Design for biaxial bending and shear for all auto generated load combinations.
  • For braced and in-plane load effects the design method follows Section 11 of AS 3600-2009.
  • For other cases the RC Column design method is used.
  • Axial checks cater for both compression and tension forces, for the braced and unbraced (short & slender) conditions, including the provisions of plain wall and end zones.
  • Similar to RC Columns, design covers confinement to the core as per AS 3600-2009, cl. 10.7.3.

Slab Design Features

  • Design of both slab panels and patches for bending following Clause 9.1.
  • Deflection Check following Clause 9.3 via the span to depth ratio limit method.
  • Similar to the method for RC Beams, a Crack Control check is carried out for slab panels  - the service moment is calculated and limits applied for bar tensile stress and maximum bar size and spacing.

NORDIC EUROCODES -  New!  National Annex (NA) Support

Three new Head Codes are added for Eurocode design for both concrete and steel to the National Annex’s (NA’s) of the following countries:

  • Finland (Eurocode) – EC with Finnish NA’s
  • Norway (Eurocode) – EC with Norwegian NA’s
  • Sweden (Eurocode) – EC with Swedish NA’s

For new models these can be set via Home > Settings and for existing models via Home > Model Settings > Design code.

  • The following set-up process for new models is recommended for engineers designing to these codes:
    • Import for example the Finland Setting via Home > Settings > Settings Sets > Import...
    • Set the imported settings to active before selecting OK on the Settings dialog.
  • The following set-up process for existing models is recommended for engineers designing to these codes:
    • Select the desired country Head Code for one of the new countries e.g. “Finland (Eurocode)” in Model Settings
    • Ensure that the “Design Codes” box displays the desired Action and Resistance codes and National Annexes.


For all these Headcodes, the following general features/areas are updated:

  • New Building attributes (displayed in Properties Window when “Structure” heading of Workspace Structure Tree selected):
    • For Finland a new Consequence Class setting is added which defines the factor kFl – an additional factor used in the strength combinations (and automatically applied in the Combinations Generator).
    • For Sweden a new Reliability Class setting is added which defines the factor ?d – an additional factor used in the strength combinations (and automatically applied in the Combinations Generator).
  • Loadcase types:
    • Additional loadcase types are added for Finland and Sweden for Snow loading in addition to Snow and Snow Drift.  These all have separate ψ factors used in the creation of combinations.
  • The Snow Wizard - the Wizard is comprehensively updated for all new Head Code Countries notable items being:
    • For Finland and Norway settings are added for the effect of Topography (Very wind swept, Normal and Sheltered)
    • For Norway, Snow load is determined from the site altitude and reference to characteristic snow load relative to a given municipality location (from the NA table)
    • Calculation of snow load shape coefficients ? and drift lengths ls are updated appropriate to the selected Head Code.
  • The Wind Wizard - the Wind Wizard is comprehensively updated for all new Head Code Countries notable items being:
    • Calculation of wind zones and generation of wind loadcase is exactly as per the (already existing) Singapore NA.  Note that the Structural Factor cscd is user-defined.
    • Finland:
      • Basic Wind Speed defaults to 21 m/s.
      • 5 terrain categories options are added (0, I, II, III, IV).
      • Note that thermal inversions for buildings > 100m tall are not considered.
    • Norway:
      • Basic Wind Speed defaults to 0 m/s and must be user-defined following reference to the Wind Speed map and tables of the NA.
      • A Region setting is added (Options of; Area 1, Area 2 or Area 3) representing the three different height zones in the country.
      • The orography factor (co(z)) and turbulence factor (kl) arae user-defined directly for the defined 3D or 2D orographic feature.
      • Note that transition zones between changes in terrain category are not considered.
    • Sweden:
      • Basic Wind Speed defaults to 0 m/s and must be user-defined following reference to the Wind Speed map and tables of the NA
      • Note that tall neighbouring structures and obstructions are not considered
  • The Seismic Wizard:
    • Finland and Sweden have no NA for EC1998 – the Eurocode (Eurocode) Seismic Wizard is therefore used for these Headcodes.
    • Norway does have an NA for EC1998 - the following details are accordingly implemented for this Headcode:
      • The spectrum type is not required by the NA and is removed.
      • The ϕ factor for Imposed load types A, B and C is set = 1.0 (not 0.8).
      • Norway specific settings are added for; soil factors,  γI importance factors and spectrum (TB, TC and TD factors).
  • Combinations - manual combinations and the Combination Wizard have been updated to cater for:
    • New building attributes (kFl and γd).
    • Revised ψ factors.

Steel Design

All Steel members can be designed to the new Headcodes - the following noteable updates/ settings are made:

  • Steel grades:
    • As per Europe Eurocode
  • Cold formed grades:
    • Norway - as per Europe Eurocode
    • Finland & Sweden - 8 additional grades are added.
  • Order Lists
    • Default Order Lists are added for the Swedish Head Code and will be set as default as long as the engineer has the Sweden Settings active
  • Buckling checks:
    • Note that for the determination of interaction factors kyy, kyz, kzy, kzz, for calculating Mcr:
      • Method 2 will always be used, regardless of the NA selected.
      • Please note that, while the Swedish NA requires Method 1 to be used, in this release Tekla Structural Designer will still use Method 2.
  • The following NA dependent variables are set appropriately for the selected head code:
    • Partial Safety Factors - ?M0, ?M1, ?M2
    • LTB factors - λLT,0 , β
    • Mcr modification factor f - Finland = 1.0
    • Shear web buckling - η
  • Design of composite beams to the new Headcodes is currently beyond the scope.

Concrete Design

All RC members and objects can be designed to the new Headcodes.  From a thorough review across all the new country NAs, the unique Nationally Determined Parameters (NDPs) set by each were determined and implemented, notably:

  • Beams
    • A total of 45 NDPs are identified and implemented.
    • For example; for the Finnish NA, Bending design Cl. 3.1.6(1)P - Long term comp strength factor αcc = 0.85; for the Norwegian NA, Shear design Cl. 6.2.2(1) - Shear strength reduction factor, CRd,c = 0.15 / γc ; for the Swedish NA, Bar limits Cl. - Maximum area of steel, As,max = unlimited
  • Columns
    • A total of 25 NDPs are identified and implemented.
    • For example; for the Finnish NA, Axial loading Cl. 7.2(5) - Tensile strength reduction factor, k3 = 0.6; for the Norwegian NA, Bending design Cl. -  Slenderness limit, λlim = 13*A*B*C/√n ; for the Swedish NA, Bar limits Cl. 9.5.2(2) - Column minimum area of steel, As,min = 0.002*Ac.
  • Walls
    • A total of 34 NDPs are identified and implemented.
    • For example; for the Finnish NA, Shear design Cl. 3.1.6(1)P - Long term comp strength factor, αccw = 0.85; for the Norwegian NA, Bar limits Cl. 9.5.2(1) - Column minimum bar diameter, φ = 10 mm; for the Swedish NA,  Axial loading Cl. 7.2(5) - Tensile strength reduction factor, k3 = 1.0
  • Slabs (panels and patches) and Slab Punching Checks
    • A total of 17 NDPs for slabs and 14 NDPs for punching checks are identified and implemented.
    • For example; for the Finnish NA, Span to depth ratio Cl. 7.4.2(2) - Structural system factor, k = 0.8 (simply supported), 1.0 (end span), 1.2 (internal), 0.3 (cantilever); for the Norwegian NA, Punching shear design Cl. 6.4.4(1) - Punching strength reduction factor, CRd,c = 0.15 / γc ; for the Swedish NA, Bar limits Cl. - Maximum area of steel, As,max = unlimited
  • Isolated Foundations and Pile Caps
    • A total of 28 NDPs for Isolated Foundations and 31 NDPs Pile Caps are identified and implemented.

Significant Enhancements

General & Modelling

Workflow & Performance Enhancements

  • To aid the interactive design of parts of a model - after an overall design or running a separate analysis process - the Structure Tree > Check and Design commands are now extended to the automated Member and Wall groups of the tree.  Each sub-group of these can now be selected for Check/Design of its entire contents so, for example, all Concrete Columns or Walls, or all steel beams of a certain size, can easily be checked or designed in a single operation.

    TSD 2018 Design of Parts.png
  • Punching Checks - similar new context menu setting for Punching Checks are also added to the Structure Tree making it possible to either Check or Design checks only in a selected Level or selected Sub structure, rather than for the entire model (4265).
  • Analysis Phase Performance
    • Data handling to/from the analysis Solver was refined for the new slab deflection analysis which has led to performance enhancements in the main building analyses also.
    • Chasedown analysis is now performed in parallel.
    • The benefits of all the above are difficult to quantify precisely as they are heavily model and operation dependent.  However, as an example, improvements in analysis time of the order of 50% over previous versions are achievable.
  • Design Phase Performance
    • Parallel processing - to take advantage of modern multi-core processors use of this capability is extended to other areas, for example a number of check procedures, such as Punching Shear checks, are now performed in parallel.

BIM Integration

Structural BIM Import Enhancements

  • Integration with Tekla Structures 2018 - this version features a better structural workflow and improved link with Tekla Structures 2018, especially for the scenario of starting in Tekla Structures 2018 and linking to Tekla Structural Designer.
    • A new export from Tekla Structures uses the Analytical Model, rather than the Physical Model.  The Tekla Structures Analytical Model process is also improved to avoid unnecessary offset members, eccentric connections and non-connection of members as illustrated in the picture below.

    • Offsets between physical and analytical members are maintained from Tekla Structures 2018 to Tekla Structural Designer.
      • This relates to offsets parallel to the analysis axis and is not applicable for braces.
    • Improvements are also made to the transfer of openings in slabs and walls.
    • Overall the improved integration saves time and reduces the need for modeling twice.
  • Structural BIM Import - Steel Column Splice Offsets - splices occur  at changes of section in continuous steel columns.  They can be modelled in a various ways in the BIM Application (such as Tekla Structures or Revit).  Tekla Structural Designer import and options is improved to better handle these scenarios.
    • A new Structural BIM option is added “Ignore splice offsets in physical member positions” in the Settings dialog (Global & Model).

    • The default for this is checked on, meaning behaviour in general is similar to the previous behaviour.
      • The setting should be unchecked where both the physical and analysis offsets are modelled in the BIM application - the actual splice offset in Tekla Structural Designer will then match the offset in the BIM application.
      • It is also recommended it is unchecked where offsets are ignored for the physical and analytical model in the BIM application.
    • The BIM Export will mirror the Import setting/behaviour.
  • Section & Material Mapping - improvement are made to the range of sections and materials that are mapped for the following countries/regions*.
    • Australia
    • India
      • With the exception of Sail Sections.
    • Taiwan, Thailand and Korea
    • *Note that the improvement required updates to all components of the BIM ‘chain’; the BIM Application (e.g. Tekla Structures), the Integrator application where applicable (e.g. the Revit Integrator developed by Trimble) and Tekla Structural Designer.  Hence all these components should be updated to the latest versions for optimum operation.

New!  ADAPT Export

  • An ADAPT Export command is now added to the Home Ribbon > BIM Integration options which produces an ADAPT text file (*.inp) which can be opened in Adapt Builder for additional design of post-tensioned floor solutions.

  • The entire 3D model is exported which includes the following properties*; Levels, Materials, Section Types, Physical Model Geometry, Load Cases and Combinations, Loading, Reactions, Member Releases.
    • *It should be noted that some geometries and configurations possible in Tekla Structural Designer are beyond the scope of ADAPT and there are not exact equivalents for all properties of the Tekla Structural Designer model.  This imposes some unavoidable limitations on the Export at this time.  Some notable limitations are:
      • Only concrete materials and members are exported.
      • Only rectangular and circular column sections are supported.
      • For concrete walls, the following are not supported; wall openings, non-rectangular walls, wall extension, walls with top ends not at a level.
      • This is not an exhaustive list - please refer to the Tekla Structural Designer Help documentation for more details.

Review View

Show\Alter State Enhancements

  • A new Show\Alter State Ribbon command “Section \ Material Grade” replaces and enhances the previous “Steel +” command.   When selected, the engineer can set the active Attribute to either of new “Section” or “Material Grade” options.

    • The new “Section” Attribute allows the section sizes of members of any material to be graphically reviewed and copied - for example the section size of concrete beams and columns (including individual spans/stacks).
    • The new “Material Grade” Attribute allows the grades of members of any material to be graphically reviewed and copied  - for example the concrete grade for concrete walls (including individual panels).
  • Portal Frames are now added as a selectable Entity Type for Show/Alter State operations, facilitating graphical review and editing of Portal Frame attributes.

Utilization Ratio Display Enhancements

  • New options are added to Home > Settings > Scene to control the number and colour of Utilization Ratio legend divisions (10903,13462).
    • Up to 10 Minimum Value divisions can be specified.
    • The colour for each value can be user-selected.


Analysis & Results

Results View

  • The Results Ribbon is reorganized and rationalized as shown in the picture below.

  • Rather than individual buttons for each force/direction, the ribbon now features drop lists for each main result listing all available options.
  • For 1D Results, new “...Biaxial” options are added for Shear and Moment to simultaneously display the forces about both axes.
  • A new Beam End Reactions result is added which displays the selected Force name(s) and value(s) adjacent to the ends of beams in the Scene diagram.

    • A new “Beam End Forces” option which displays similar values is also added to Scene Content > Plan options.


Head Code BS (All Countries)

Steel Design - Single Angles  - Design for bending 
  • Design of single angles in bending is now added to complement the design for common asymmetric sections to  the BS code implemented in previous releases - namely double angles and tees.  All strength checks are performed for single angles (and tees) while LTB and Combined Buckling are beyond scope for double angles.
  • Many Single angles are Class 4 (slender) sections in bending which is catered for in the new design.
  • For slender section design, an effective cross section approach is used.  Additional design moments resulting from the shift in centroid of the effective cross section are calculated and included.
  • Current scope and limitations:
  • The following member characteristics are designed; Beam, Truss Member top and bottom.
  • Intermediate Lateral Torsional Buckling (LTB) restraints are not considered - the member can only be either fully restrained or unrestrained for LTB.
  • Angle sections are designed for; Axial Tension and Compression; Major, Minor and Biaxial Bending and Shear; Combined Axial + Bending; LTB and Compression Buckling; Combined Buckling. 
  • Angles subject to moment with high shear are beyond scope.

Head Code Eurocode

Steel Design - Beams - Design for Torsion
  • Steel beams subject to torsion can now be designed to the Eurocode using SCI P385, 'Design of Steel Beams in Torsion'.  While this is written with the UK NA in mind, it is believed that the method would be acceptable to other NAs and so its use is extended to all currently supported NAs. 
  • The design caters for torsion combined with other load effects; torsion with and without moment (biaxial) and/or shear (biaxial).
    • Axial force is ignored and an appropriate warning issued if present.
  • The following new properties to control the check are listed under the “Torsion” heading in the beam properties:
    • “Check for torsion” (default is ON)
    • “Apply rotation limit” + limit value entry box when enabled (default is OFF).  The default limit is 2 degrees, but this can be edited by the User.
    • Torsion restraint information is displayed for information only with the following assumed; Torsion - fully restrained; Warping - free.
      • Note that this applies to beam ends only - no account is taken of intermediate restraints from supported members.
  • The new design applies for the following settings and circumstances;
    • Characteristic; Beam.
    • Sections; Doubly-symmetric I-sections and structural hollow sections RHS/SHS/CHS (steel and cold formed).
    • Single span beams.
    • Pinned end connections only.
    • Check design only is supported but not auto-design.
  • The scope and procedure is as follows:
    • Open sections (doubly-symmetric I-sections) are designed only for torsion resulting from loads applied directly within the beam span - termed “Applied” torsion moment.  This includes loads applied by members connecting with the span and to both the torsion force and rotation limit checks.  Torsion resulting from loads applied outside the span is termed “Inherent” torsion.  When this is detected no checks are performed and a warning is issued.
    • Closed sections (structural hollow sections) are designed for all torsion forces when carrying out strength checks; however, when checking rotation due to torsion “applied” torsion moment only will be considered.
    • Note that web openings are beyond scope.
  • The Beam Load Analysis view includes new features to calculate and report the angle of twist θ and, for open sections, its 1st, 2nd and 3rd derivatives θ’, θ’’, and θ’’’ which are required for the torsion design (available for All Head Codes).

Head Code US

Steel Design - Beams - Plated (Built-up) Sections
  • Steel beams with plated sections can now be designed to AISC 360-05 and 360-10.  Formerly, while it was possible to define plated sections and use them in a building, no design was undertaken.
  • Scope:
    • Characteristic of Beam and non-composite only are allowed.
    • Double & single symmetric I-section are allowed.
    • Single and multi-span continuous beams and cantilever spans are allowed.
    • As with rolled I-sections, the flexure class Slender is beyond scope, but axial class Slender is allowed.
    • There is no torsion design but all other checks as for rolled sections are undertaken; axial, major & minor flexure and shear, LTB and combined forces.
    • Check design only is supported but not auto-design.
    • Web openings are not catered for.
  • Notable aspects of the new design are:
    • In minor axis shear the Cv factor is calculated & applied separately for top & bottom flanges.
    • Flexure design requires some parameters unique to plated section design when compared to that for rolled sections; notably the web plastification factors (Rpc and Rpt) in flange yielding & LTB checks.  The AISC 360-10 approach to evaluating Rpc and Rpt is adopted for AISC 360-05 also.
    • A proportioning limit check is introduced, based on Section F13.2 and eqn F13-2 of AISC 360.
    • For the combined forces check, as for rolled I-sections, equations H1-1a and H1-1b are implemented; however the check is Beyond Scope for sections that fail the proportioning limit check noted above, whether any axial force is compressive or tensile.
Steel Design - Beams - Web Openings
  • Steel beams with web openings can now be designed to AISC Design Guide 2, Steel and Composite Beams with Web Openings, and the requirements of AISC 360-10.
  • Openings are distinct from ‘holes’ - they are relatively large voids cut into the webs of beams, required for the integration of services within the beam depth, such as ducting etc.
  • Openings are defined in a simple and intuitive manner with real-time graphical confirmation of the opening dimensions and location(s).  The definition process is ‘intelligent’ - dimensional constraints are constantly checked and the engineer is warned if any are contravened.  Graphical icons indicate when the proximity of openings becomes too close and tooltips in the definition dialog guide the engineer with allowable dimension values.

  • Design details contain extensive output for the new checks and calculations for web openings, all of which can be included in reports.
  • The Design process is ostensibly to AISC 360 with the following notes/provisos:
    • AISC 360 contains no detailed guidance in any dated version for beams with large and/or multiple openings.
    • Reference has been made to AISC Design Guide Series – DG2.
    • We note however that DG2 was written in 1990, references AISC 360 1986,  and was last updated in 2003.
    • Where applicable, Tekla Structural Designer applies the provisions of AISC 360-10.
  • Scope and usage:
    • The member characteristic of Beam only is supported - both composite and non-composite construction are allowed.
    • Auto-design is not catered for - the setting for this must be unchecked in order for openings to be defined.
    • The opening shape can be rectangular and circular only.
    • Equal flanged rolled I-sections are allowed but not plated sections.
    • Beams must be pin ended (simply supported) - multi-span continuous beams and cantilever spans are not allowed.
    • Curved, haunched and tapered beams are not allowed.
    • Design is to LRFD only, not ASD.
    • DG2 covers Compact sections (Class 1 & 2) only so Class 3 and 4 are not allowed.
  • Notable aspects of the new design are:
    • The are no checks in DG2 on web posts, so openings must be sufficiently widely spaced to be considered ‘isolated’.
    • Circular openings are treated as an equivalent rectangle - 0.45 φo wide by 0.9 φo high.
    • Opening can be ‘reinforced’ (stiffened):
      • This can be to one side or both sides but is always top and bottom.
      • No checks are performed on the reinforcement and its welds per se, but its influence on the opening design is considered.
    • Deflections:
      • While DG2 gives simplified rules for limited cases, these are difficult to apply to the more general scenarios of geometry and loading encountered in Tekla Structural Designer - hence these simplified rules are not implemented.
      • Instead Tekla Structural Designer uses a more generally applicable approach from first principles  as per Eurocode and BS design.
    • In addition to checking the moment-shear interaction at the opening centerline, the following design aspects are also considered:
      • Buckling of the top tee in compression.
      • The influence of openings on LTB of the beam - each unrestrained segment being checked for each opening within it.
      • The proximity of ‘concentrated loads’ to openings.
      • For composite beams – the effect of slab reinforcement and the minimum number of shear connectors required adjacent to the opening.

General Fixes & Enhancements

General & Modelling

  • Performance and Stability - a number of fixes and enhancements are made to improve general program stability and performance.
  • Materials - Grades - Eurocode Head Code (All Countries):
    • Steel - the following new grades are added for S235 Grade steel; S235, S235 JR, S235 J0, S235 J2 (4596).
    • Timber - grades/ values are updated in accordance with Eurocode Timber strength classes document BS EN338:2016 (53035).
  • Grid Lines - user-defined grid line User names and original unique numbers were not retained when a grid line was moved to another Architectural grid system by editing its “Grid” property (14692).
  • Sections - Plated Sections - a number of improvements are made to the definition of plated sections:
    • Previously it was not possible to select a plate of less than 150mm in breadth for the top or bottom flange of a plated I-section beam (14702).
    • The manner of definition for Plated Beam and Column sections reverts to that prior to 2017i - the overall section depth can now again be manually entered as any value rather than being selected from a drop-down list of fixed plate sizes in the database (54404).
  • Beams - Composite Beams - the automated effective width calculation now ignores brace members when detecting the proximity of members which may limit the width (13126, 14262).
  • Sloping Members - Size - the correct physical length, rather the the projected horizontal length, is now shown in the Properties > Size page for inclined members of all types (14755).
  • Property Sets - Braces - the Tension Only and Compression Only property is now added to property sets of braces (4592).
  • BIM Integration - Cellbeam Export:
    • In some circumstances for curved beams supported purlin reaction loads were not exported to Cellbeam (14698).
    • For the circumstance of loads applied by other means (such as a connected column) a warning is added on export that (in addition to directly applied loads) only reactions from supported transverse beams are considered (14651).
  • Concrete Walls - Meshed Walls - this issue relates only to version 2017 ( in March 2017), in which it was introduced, and subsequent releases.  Where beams connected to a wall between levels the beam analysis elements were not correctly connected to and supported by the wall mesh elements.  A workaround was to create a construction level at the wall and beam intersection point - this is no longer required (14772).


  • Roof Panels - Snow Loading - for the circumstance of overlapping slab and roof items (for example on a flat-roofed building), roof panels had a setting “Decompose only wind”.   When set on, only wind loads were decomposed by the panel, not any other area loads in the plane and area of the panel such as gravity loads (which would be decomposed by the overlapping slab items).  This setting is now extended to include snow loads (previously these also would not be decomposed by the roof panel with the setting on) and renamed “Decompose only wind & snow ” so that the same behaviour occurs for snow loads applied to roof panels by the Snow Wizard (14680).

  • Snow Wizard - US Head Code - for snow drift loads, the upper and lower roof lengths were incorrectly transposed in the calculations for the windward and leeward drift heights (14742).
  • Seismic Wizard Loading - ELF - for a specific and relatively rare circumstance - where columns or parapet posts were stacked on a column at a node to which braces also connected - the static seismic forces could be applied opposite to the correct direction.  Where this occurred it would be apparent from a review of the Seismic forces and could be worked around by using a vertical beam instead of a column or parapet post.  The workaround is no longer required (14793).
  • Load Decomposition - Area and Patch Loads - in some circumstances, for loads applied to roof panels in inclined planes, area and varying patch loads would fail to decompose correctly.  Where this occurred a warning that applied loads and reactions did not balance would be issued in the Process Window , and errors would be shown for the affected load case(s) in the Project Workspace >  Loading check window (14824, 14861).
  • Load Combinations - Generator - Eurocode - for both the Singapore and Malaysia Eurocode NA's, the values of the accompanying wind load factors ?0 and ?1 are corrected from 0.6 and 0.5 respectively to 0.5 and 0.2 .  The associated Help topic table for psi factors  (14768).


  • Supports - a new validation check is added for models containing supports at multiple levels.  For the circumstance where such supports may have been applied or left remaining inadvertently, a new warning “Raised support provides lateral restraint” is issued where one or more supports, that are not at the lowest Z elevation of all the supports, have Fx or Fy or Mz set to "fixed".  The check caters for the circumstance of sloping mat foundations and wall bases (4480).
    • As with an number of optional validations, should the engineer wish this can be conveniently disabled via the right-click context menu as shown in the picture below.


Analysis & Results

  • Analyse All (Static) - Drift and Wind Drift - in a similar manner to Sway calculations/ checks currently, the calculations for Drift (for the US Head Code) and Wind Drift checks are now performed by the Analyse All (Static) process.  The Status of the checks are reflected in the Project Workspace > Status tree under the Design heading, and the checks are listed in the Review Data > Seismic Drift table and the associated Report item (54622).



  • Concrete Design:
    • Columns and Walls  - All Head Codes - Minimum Moments - for the specific circumstance of the moments from analysis being < the minimum moment for both axes, design codes generally require that the minimum moment need only be considered acting about one axis at a time.  However, in previous versions Tekla Structural Designer always applied the minimum moment in both directions simultaneously, producing a bi-axial moment and what might be considered an over-conservative design (4599, 12047).  The behaviour is now as follows:
      • For any section that is not circular or rectangular, the minimum moment is always applied as before about both axes, the rationale being:
        • Firstly, we believe, the logical intention behind the requirement is that a cross section should be able to resist a minimum moment in every direction.  However, if the local X and Y axes of a member are not aligned to the strongest and weakest axes (e.g. for an L-shape section) then applying the minimum in only one of the X or Y directions will not guarantee meeting the intention.  Hence we consider applying the moment about both axes together for this contingency is a safe and conservative approach.
      • For rectangular (non-square) sections, the minimum moment is applied in the weaker direction.
      • For square and circular sections, the minimum moment is applied in the direction with the smaller analysis moment.
    • Beams - Check design - for beams in ‘check mode’ (i.e. when the autodesign setting is off), following edits to section size and/or cover, consequent changes in the vertical locations of reinforcement bars are now automatically updated when running design checks, for the design and subsequently produced drawings.  Previously in this circumstance it was necessary to open the beam interactive design dialog and make a change to update the bar locations (14453).
  • Steel Design:
    • Beams:
      • Camber - when the camber value is automatically calculated and applied, a “to nearest” interval value in Beam Properties > Camber settings is used to round the calculated “precise” value to a practical one in increments of the interval.  Previously camber values could be rounded up to the nearest interval rather than down.  Now the value is always  rounded down to the nearest interval value so that, for example, for  “to nearest” = 0.25 in, an automatically calculated precise value of  1.38 in will be rounded down to 1.25 in (14822).
      • Web Openings  - Eurocode and BS Head Codes - Steel and Composite - for multiple openings, a Beyond Scope design status could occur for some openings when all openings were not defined in order of their distance from the start of the beam.  This could be worked around by clicking the “Sort” button on the Web openings page of beam properties.  Openings are now automatically sorted during the design process so the error no longer occurs and the work around is no longer required (14449).
    • Single and Double Angle Sections - Taiwan Sections - a design error would occur due to the omission of some section properties in the section database.  The required section properties are now added and design completes (14761).
  • Seismic Design - Seismic Drift - this relates to the the ASCE, UBC and EC Seismic Loading Codes which have a seismic stability coefficient theta (θ).
    • Following design (of models including seismic combinations) the value of theta is checked, for each direction, and a warning now issued when the value is such that P-delta effects should be accounted for, but only First-order analysis has been set in Design Options > Analysis.  Note that the upper limit for the coefficient “theta_max” (θmax)  is still considered and a Beyond Scope status applied when this is exceeded.
    • The warning is issued in a similar manner to that currently for Sway and Drift; as a Warning Status icon in the Project Workspace > Status tree under Design > Seismic Drift; in the Review Data > Seismic Drift table and the associated Report item.  When the warning is triggered, the following warning text is displayed in Seismic Drift details "Warning - P-delta effects must be considered - run Second-order analysis (Design / Options)"” (54578).
  • Piled Rafts and Pile Caps - the critical combination was not identified correctly in pile design details when the pile tensile capacity was set to 0 kN.  The issue affected only the display of the critical combination, not design results, and could be worked around by entering a nominal small value for the tensile capacity.  The workaround is no longer required (14722).

Head Code BS

  • Steel Design:
    • Gable Posts - the enhancements listed below are made to design for the Gable Post characteristic.  Note that the previous recommended workaround for the limitations the enhancements address was to use either a beam or column characteristic as per Product Bulletin PBTSD-1711-1.  This is no longer necessary for the BS Head Code, but the bulletin advice remains in place for the Eurocode (54271, 54272, 54274):
      • Member properties now include settings for Lateral and Strut restraints similar to those for the column characteristic.
      • Deflection checks for Wind load are now performed.
      • LTB and combined buckling checks are now performed.
    • Beams - LTB - in certain circumstances an LTB check could be performed and fail status assigned when the maximum moment was less than major moment ignored forces level (14821).
  • Concrete Design - Beams - beam reinforcement autodesign now considers the code requirement of link size being least 0.25* the compression reinforcement diameter.  Previously this requirement was checked only after the autodesign process, meaning the check could fail following an auto-design (13867).

Head Code EC

  • Composite Beam Design:
    • Deflection - the Post Composite deflection values reported as the “Design Value”, in the design summary table, and the “Deflection with partial shear connection” in the check details are now consistent (14759).
    • Precast Concrete Planks - the upper  limit of SCI P401 4.2.1 is now applied to the automatically calculated effective width.  Note that for the purposes of this the total concrete infill is currently assumed to be 500mm on each side (14574).
  • Concrete Design - Columns and Walls - for the slender case and where minimum moments apply, the minimum moments are no longer amplified producing a less conservative result (54664).

Head Code India

  • Foundations - Isolated Pad and Strip - the adjusted calculation of design forces method which was implemented in 2017i for the ACI and BS codes is now implemented for the Indian code (54223):
    • Previously, the method of determining a design base pressure distribution for base (internal) design forces calculation ignored foundation selfweight, soil selfweight, dead or imposed load surcharge.  Provided all the pressures determined were ≥ 0 this was valid as these loads do not generate bending or shear in the base.  This would be the case for most models/ bases, but not those which were sufficiently lightly-loaded such that some pressures were < 0.   For such cases this could lead to design being beyond scope and failure of auto-design to find a reasonable solution for size.
    • The full pressure profile is now calculated and then reduced (for the effects of foundation selfweight, soil selfweight, dead or imposed load surcharge) to calculate the design forces.  This means it can now cater for situations where full pressure is ≥ 0, but the minimum design pressure can be < 0

Head Code US

  • Steel Seismic Design :
    • Beams - the angle of braces within an SCBF displayed in SCBF beam design details, for seismic forces transmitted to the beam, could be incorrect.  This affected only the presentation of results, not the calculation of seismic forces (14752).
    • Beams and Columns - for beams and columns forming part of an SFRS, the brace and beam capacity values used in the beam or column design were incorrectly multiplied by the redundancy factor ? (set in the SFRS page of the Seismic wizard) producing an over conservative result (14750, 14777).
    • Braces - Seismic Strength - for braces forming part of an SCBF, clause F2.5b(3) of AISC 341  was incorrectly always applied resulting in all HSS sizes failing the check.  The check is now correctly omitted (as per the Help Documentation) when the brace effective area Ae = the gross area Ag (which is always the case for HSS’s) or the User percentage = 100% (i.e. no reduction is made in the section) (14755).
  • Concrete Design - Beams - in some circumstances, for beams with autodesign set to off, out of date required torsion reinforcement area (At) data could be retained and used in checks producing an erroneous design status.  This could be worked around by auto-designing the reinforcement for affected beams.  The torsion reinforcement area is now calculated as part of the check design process and the workaround is no longer required (54804).

Reports & Drawings

  • Reports - Member Design - member user names (set via the Properties Window > Name > User name option) are now used for individual member design tables in the Member design reports (14625).


The number in brackets after an item denotes an internal reference number.  This can be quoted to your local Support Department should further information on an item be required.

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