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Software Release History - Version 19

Version 19.1 | Version 19.0

New Facilities and Improvements in LUSAS Version 19.1

V19.1-2 made available on 8 February 2022

This is a major release of new facilitites, enhancements and change requests

New software product: LNG Tank Analysis and Design System

  • The 'LUSAS LNG Tank Analysis and Design System' allows engineers to automatically create a range of 2D and 3D finite element models of full containment circular tanks from user-defined parameters. From these models, a range of analyses can be performed, and design checks can be optionally carried out for specified load combinations.

Steel Frame Design

  • The Steel Frame Design software option has been extended to include design checks for BS5400-3:2000

Concrete Creep and Shrinkage

  • The range of concrete creep and shrinkage material models has been extended to include those for Chinese code JTG 3362-2018 and fib Model Code 2010.
  • For Codes of Practice that include suitable clauses, material properties and creep/shrinkage behaviours can be adjusted according to a prevailing temperature during the service life of the structure. This includes CEB-FIP Model Code 1990, fib Model Code 2010, and JTG 3362-2018.
  • The age of structural elements at the time of their activation can now be calculated with adjustment for temperature during curing.


  • Time dependent prestress capabilities have been extended to include those for Chinese code JTG 3362-2018 and fib Model Code 2010.

Vehicle Load Optimisation

  • The Vehicle Load Optimisation facility has been extended to support optimised loading and custom vehicles for Unites States of America AASHTO MBE Section 6A (LRFR) and United Kingdom CS 458 rev 0 with ALL Model 1.

RC Frame Design

  • RC Frame design now allows the direction of the neutral axis to be defined for uniaxial bending as part of defining the RC design attributes for all supported design codes.

Design combinations

  • The Design combinations facility now supports CS 454, IRC: 6-2017, EN1990 for Railway Bridges and Footbridges - for Recommended Values and Irish, and UK National Annexes, and EN1990 for Highways Bridges and Footbridges for the Italian National Annex.
  • The design combinations implementation for Highway Bridges for EN1990 for Recommended Values, Irish, and UK National Annexes has been extended to include 'Persistent Combination Set C'.

Cursor-based box selections

  • A right-to-left definition of box extents can be optionally set to select all features crossed by the selection box (as often used by CAD software), rather than include only those items wholly inside the selection box. 

Thick beam warping

  • For thick beams that support warping, torsional end conditions can now be defined.

LUSAS Teaching and Training version limits increased

  • The Teaching and Training version of LUSAS, which restricts the size of model that can be solved, now has the following increased limits:




Degrees of Freedom







File export

  • Export of LUSAS model data to a Visual Basic Script file is now provided.

Improved exporting of results data for use by the Composite Deck Designer (PontiEC4)

  • Exporting of results can now be used with 2D grillage or 3D analysis models made from beams, shells, or a combination of those element types.
  • Composite Design Member details are now used when exporting force and moment results data for use in carrying out design checks by the Composite Deck Designer (PontiEC4) software option. As a consequence, beam/shell slice resultants can now also be exported.

For more information see Composite Bridge Deck Design (PontiEC4)

Associated model data

  • The 'Associated Model Data' folder, that holds files created in the course of a building a model and running an analysis, is now named 'LusasFiles32' for a 32-bit installation.
  • The previous ability to specify alternative locations of files that are created in the course of building a model and running the various analyses associated with it, as specified via the LUSAS configuration utility, has been removed.

Restricted 64-bit LUSAS Modeller (Beta)

  • Version 19.1 offers a new restricted 64-bit beta version of Modeller that should only be used if advised to do so by LUSAS Technical Support. Users are recommended to keep using 32-bit Modeller as geometry cannot be edited in this beta version.

New Facilities and Improvements in LUSAS Version 19.0

Release history

V19.0-3 made available on 3 January 2020

This is an error fix release to correct an urgent software issue preventing the loading of any results file generated since midnight 1st January 2021 into LUSAS Modeller. 

Other error fixes and change requests are included.

V19.0-2 made available on 27 July 2020

This is a major release of new facilitites, enhancements and change requests

In summary:

  • Steel / Composite Bridge Wizard introduced for quick and easy modelling of slab-on-beam composite I-girder bridges.
  • Composite Bridge Deck design introduced for AASHTO LRFD 8th Edition.
  • Steel Frame design has been extended to include AISC-360 and GB50017.
  • Reinforced Concrete frame design extended to include AASHTO 8th Edition, AS5100.5-2017, IRC:112-2011 and CSA S6-14.
  • Vehicle load optimisation has been extended to include IRC:6-2017.
  • Geotechnical modelling capabilities extended to include additional Ko models, Phi-c reduction, drained and undrained conditions, and a Hoek-Brown material model.
  • Bridge deck (grillage) attributes introduced for slab, and girder with top slab modelling of grillages.
  • Bridge deck temperature and shrinkage profile loading.
  • General variation of temperature or strain through-section
  • Generate influences from beam / shell resultants and inspection locations.
  • Model view "orientation cube" introduced.
  • Branched analyses introduced.
  • Access to Fast and Frontal Solvers provided.
  • Direct Method Influence analysis improvements
  • Rail Track Analysis enhancements.
  • Slice resultants improvements.
  • Results averaging speed-up.
  • New and updated worked examples.

New facilities and improvements in more detail:

Steel/Composite Bridge Modelling

Composite Bridge Deck Design

Steel Frame Design

Reinforced Concrete Frame Design

  • RC frame design software option now supports:
    • AASHTO 8th Ed. (USA)
    • AS5100.5-2017 (Australia)
    • IRC:112-2011 (India)
    • CSA S6-14 (Canada)

Reinforced Concrete Slab Design

Vehicle Load Optimisation


General modelling, analysis and results improvements


New and updated worked examples


Steel / Composite Bridge Modelling Wizard

The Steel Composite Bridge Wizard generates the model geometry and corresponding mesh, geometric, material, support and local coordinate attributes for models of slab-on-beam composite I-girder bridges where the slab and web are modelled with shell elements and the top and bottom flanges, web stiffeners and bracing are modelled using beam elements.

Models can be defined that accommodate:

  • Straight or curved decks of constant radius.
  • An arbitrary skew, where a skew can additionally be set per support and interpolated across the spans.
  • Any number of spans and supports.
  • Square and skew bracing.
  • Transverse stiffeners.
  • Design utilities for design checking against supported design codes.

Example of a curved multi-span steel composite bridge deck with bracing created by the wizard


Composite Bridge Deck Design

The Composite Bridge Deck Design software option can be used with new or existing bridge models for software licences that support this facility. It is for use with 2D Grillage/Plate and 3D element model types. When used with LUSAS Bridge LT only 3D beam and 2D grillage models are permitted.

The Composite Bridge Deck Design option provides a consistent approach to design, regardless of the analysis approach adopted, using slice resultants to calculate design forces. This allows an analysis model to be created without having to define design details initially. It allows for the complexity of the analysis model to be increased without changing the design data, and also permits a number of changes to be made to the design information to see what the effect of a particular change would be, without having to change or solve the analysis model each time.

The following steps are required to carry out a composite bridge deck design check:

  1. Create a model of the bridge deck by using the Steel Composite Bridge Wizard, or by using the grillage wizard, or by manually creating an appropriate model, and solve it to obtain results.
  2. Define a composite bridge deck design member for each girder (simple spans) or series of girders (continuous spans) of interest in the model.
  3. Specify the design code to be used by selecting the Design> Composite Deck Design menu item.
  4. Define a results utility This identifies the design members for which calculations are required and brings together the loadcases / combinations appropriate to the various limit state checks.
  5. View the results in tabular format, and optionally add selected results to a model report.

Design codes supported

The following design code is currently supported:

  • AASHTO LRFD 8th Edition. (USA) - AASHTO LRFD Bridge Design Specifications 8th edition, American Association of State Highway and Transportation Officials 2017.

Steel Frame Design improvements

The Steel Frame Design software option now supports 

  • ANSI/AISC 360-16 Specification for Structural Steel Buildings, American Institute of Steel Construction, Chicago, July 2016
  • GB50017-2017 Standard for design of steel structures, China Architecture & Building Press, China.

Reinforced Concrete Frame Design improvements

The RC Frame Design software option now supports:

  • AASHTO 8th Ed. (USA)
  • AS5100.5-2017 (Australia)
  • CSA S6-14 (Canada)
  • IRC:112-2011 (India)

Reinforced Concrete Slab/Wall Design improvements

The reinforced concrete slab/wall design facility now supports:

  • GB 50010-2010 Code for design of concrete structures, China Architecture & Building Press, Beijing.

Vehicle load optimisation enhancements

The Vehicle Load Optimisation software option now supports:

  • India IRC:6-2017 Standard Specifications and Code of Practice for Road Bridges - Section : II - Loads and Stresses (7th Revision) Indian Roads Congress, New Delhi.


Additional K0 models

Two additional K0 initialisation options, 'Wroth' and 'OCR sin(phi)', have been added to the Modified Cam Clay material model to allow initial stresses in soil to be calculated.

Phi-c reduction

Phi-c reduction attributes can now be defined and assigned to a model to assess soil stability and safety factors for soil that is represented by Mohr-Coulomb or Hoek-Brown material models. Attributes can be assigned to all or just some of the relevant features in a model, allowing the safety of a particular slope (for example) in a large analysis to be evaluated without other parts of the model being affected. Assignment is made to a particular loadcase or analysis stage, which defines the applicable loading, boundary conditions and activation status.

By its very nature, a phi-c reduction analysis will always run until solution failure, so it is best used in branched analyses where it can be used to study safety factors at several stages of construction without terminating the solution.

Drained and undrained conditions

Drained and Undrained attributes can be defined from the Attributes > Pore Water Pressures... menu item. They are used to define regions of a model where the soil is drained or undrained.

Drained and undrained attributes can be assigned to features representing soil that are meshed with two phase elements and modelled with two-phase materials in both 2D or 3D models. The use of such attributes is a conceptual shortcut from the beginning to the end of a consolidation analysis, representing the extreme undrained and drained conditions.

Hoek-Brown material model

The Hoek-Brown model is now supported. This is an elastic-perfectly-plastic constitutive model suitable for the modelling of rock failure. It is an empirical model, and its parameters are based on both laboratory test data, and visual observation of the rock. The model can be used with standard continuum elements as well as the two-phase elements.

General modelling, material and results enhancements

Bridge Deck (Grillage) attributes introduced

Bridge Deck (Grillage) geometric attributes have been introduced to define geometric properties of specific types of bridge decks that are analysed with reference to, or derived from grillage formulae published by Hambly and others.

When assigned to a model along with a new Bridge Deck (Grillage) material attribute, which contains separate material definitions for the slab, girders, slab and reinforcement (for cracked sections) that are defined in the relevant Bridge Deck (Grillage) geometric attribute, users can more easily analyse the different phases of construction of these types of bridge decks with one model by the use of the multiple analysis facility. In short, one set of grillage geometric attributes is suitable for the life of a bridge, as the sections do not change, whereas several material attributes may be needed to represent the in-construction, short term, and long term cases.


Bridge deck temperature and shrinkage profile loading

Bridge deck temperature profile loading can be defined for the following design codes.

  • AASHTO 8th
  • AS 5100.2:2017
  • EN1991-1-5:2003 Approach 1
  • EN1991-1-5:2003 Approach 2

Bridge deck shrinkage profile loading currently supports:

  • AASHTO 8th

General variation of temperature or strain through-section

For general use, a temperature/strain profile loading can be defined by stating the temperature of the top of the section followed by defining a series of segment thicknesses and corresponding values for the specific height at which the expression is being evaluated. Segment thicknesses and temperature/strain may be stated as a single value, or as expressions, making it possible to replicate expressions in bridge industry Codes of Practice and define code-specific profiles that are not currently supported elsewhere in LUSAS.

Defined profiles can be visualised for a stated visualisation height. The same profile may be assigned to multiple geometric sections of differing heights.


Generate influences from beam/shell resultants and inspection locations

Direct Method Influences can now be generated from beam/shell slice resultant locations and at inspection locations. Direct Method Influence attributes can be assigned to pre-defined Inspection locations, or to Beam/Shell Slices using the 'Assign to' context menu item for the DMI attribute, and then selecting the inspection points or beam/shell slices to which the assignment should be made on the Influence Assignment dialog that subsequently appears.

The ability to assign DMI attributes to Beam/Shell Slices now makes it possible to use the Vehicle Load optimisation facility on bridge decks idealised using mixed beam and shell elements.

Model view "Orientation cube" introduced

An orientation cube can now be optionally displayed in each model view window. This provides visual feedback on the orientation of a model, and rotates and updates as the model is rotated or orientated. The top of the cube is aligned to the defined vertical axis for the model.

The orientation cube has labelled faces with default names of Left, Right, Bottom, Top, Back and Front, and edges and corners that highlight when a cursor is moved over them. Selecting a face, edge or corner of the cube will orientate the model to be viewed from the selected direction. The model can also be dynamically rotated by clicking and dragging to rotate the orientation cube.

Home, Dynamic Rotation, Resize, and Perspective buttons can be optionally added beneath the axis cube for easy selection.


Branched analysis introduced

Analysis branches may be added to the Analyses Treeview by selecting the New > Branch context menu item for any loadcase in the Analyses Treeview that has (or inherits) a nonlinear or transient control. They allow the creation and solution of one or more sub-analyses to investigate the response of the model at a particular loadcase or "stage".

Examples of use include:

  • Carrying out a linear moving load analysis of construction equipment during each stage of the construction of a segmental bridge deck,
  • Performing an eigenvalue natural frequency analysis or a buckling analysis during construction.
  • Performing a phi-c reduction analysis to derive safety factors for a geotechnical model from each stage in an excavation process.
  • Performing an earthquake analysis where gravity is applied in a static nonlinear step, then the earthquake is run as a transient branch. Several sample earthquakes may be run in each branch.

Any number of sub-analyses may be defined for a single parent loadcase.

Access to Fastest available and Frontal Solvers provided

The Fast Multi-frontal solver is now made available by default to new clients.

Two Solver-related radio buttons previously included at the bottom of the 'Model properties' dialog have been replaced with a droplist control on the dialog that additionally allows specifying solution options on the 'Solve Now' dialog. These now allow for solving by the fastest available and appropriate solver for the task in hand, or the frontal solver, which provides more error diagnostics should issues arise. An option to only solve for the first loadcase (for quick model attribute assignment checking purposes) is also included.



Direct method Influence analysis improvements

Direct Method Influence analysis is now faster because the Solver results file is now generated at the same time as the stress recovery stage, saving significant processing time.

Larger Direct Method Influence analyses can now be carried out with either a finer grid or a finer mesh without manually setting any additional parameters. The analysis is split into batches that make maximum utilisation of the memory available but which ensure that no matter how large the DMI analysis, it will solve successfully.

Rail Track Analysis enhancements

The LUSAS Rail Track Analysis software option now includes the following new features / enhancements:

  • Bearings can now be modelled offset (inboard) from the ends of the decks.
  • Multiple Train Loading Groups can be analysed within the same analysis.
  • Avoidance of stubby elements in the modelling.
  • Improved pier modelling.
  • Train loads are allowed to be outside the extents of the model. This allows long trains to be passed over structures without having to have excessively large embankments to model the correct arrival and departure of the trainset from the structure.
  • Use it for EuroCode nomenclature of Traction loads (instead of Acceleration).
  • Significant speed up of train/rail load definition and assignment.
  • Section axes for deck and pier now included in the Geometric Properties worksheet.
  • Improved results / chart titles in the tabulated output.

Slice resultants improvements

Once defined, slice sections are now visualised immediately on the model without the need for a solve to have taken place first.

Results averaging speed-up

Averaging of element results across discontinuities has been made more efficient, reducing the time it takes to display averaged results in this situation.


User change requests

In addition to the range of new facilities and improvements listed, many user change requests have also been implemented. The originators of all requested changes to the software (some of which are included in the above list of enhancements) that have been incorporated in this release will be notified individually.


All online and printed documentation has been updated for this new release. Manuals are provided in PDF format as part of any LUSAS installation, and are also available for download from the LUSAS website.

New and Updated Worked Examples

The following new and updated examples illustrate some of the new facilities provided in this release.

Within LUSAS, see Online help > Worked Examples > For LUSAS Bridge and LUSAS Civil & Structural for details.

Other worked examples

All existing worked examples have been updated to match changes made to the software.

Individual worked examples in PDF format are provided as part of the LUSAS software download file or release DVD, and are also available from the online help. Examples are also available from the LUSAS User Area.


Potential issues opening PDF files referenced in CHM files

On some PCs, and for certain operating systems, the installation of security updates as released by Microsoft can affect the opening of PDF files from the table of contents panel within the CHM file-based help. Any links to PDF files from within help topic pages may similarly be affected.

If problems are found when attempting to open these files from within the online CHM file supplied please note the following:

  • Selected manuals are supplied in PDF format on the installation kit and these are normally installed into the <LUSAS Installation Folder>/Programs/PDF_Manuals folder.
  • Workarounds/solutions may be provided by Microsoft during the availability and support of this particular LUSAS software release.

Previous new facilities and improvements in this release

None, this is the first release of Version 19.

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