Engineering analysis and design software
Bridge design and engineering

Software Tour

Design code facilities

For steel and concrete bridge design to Eurocodes, LUSAS provides the means to carry out:

  • Traffic loading to EN1991-2
  • Member resistances to EN1993
  • 2nd order analysis for EN1993/4
  • Pedestrian dynamics to EN1990
  • Thermal actions to EN1991-1-5
  • Combining actions to EN1990
  • Execution analysis to EN1991-1-6
  • Steel and Composite deck design to Eurocodes

Vehicle load optimisation, slab design, prestress and post-tensioning, and concrete creep and shrinkage calculations are carried out in accordance with a variety of design codes, including Eurocodes. See below for more details.

Traffic loads to EN1991-2

  • National Annexes supported in the Vehicle Load Optimisation facility include those for the UK, Ireland, Italy and Sweden. Nationally Determined Parameters and the appropriate LM3 (special vehicles) for each country are included. A "recommended values" option is also available (incorporating Annex A vehicles). In all cases there is flexible selection of the special vehicles. Psi/alpha factors may also be modified.

  • Characteristic, Combination and Frequent cases can be generated with a single analysis. Suitable defaults are set, but the load groups to be included may be modified.

  • Eurocode traffic loads (including rail traffic loads) are available in a vehicle library. These may be used in any static or dynamic analysis, moved over the structure in convoys, arranged to any required pattern, and readily combined with other actions.

See Load types and combinations for more details.

Member resistances and 2nd order analysis

Elastic critical buckling load can be determined directly from an eigenvalue buckling analysis in LUSAS enabling the calculation of member resistances to EN1993 clause 6.3. The eigenvalue buckling analysis also enables an assessment of the importance of 2nd order effects, and if deemed to be important these may be obtained by carrying out a geometrically nonlinear analysis.

LUSAS allow buckling analyses to be carried out on structures idealised using beams, plates, shells, or solids or any combination. Material nonlinear effects (yielding or concrete cracking) and boundary nonlinear effects (lift-off, tension-only members etc.) can also incorporated. Animations, contours, diagrams and load / displacement graphs can be viewed for selected nodes.

Typical pedestrian bridge model

Pedestrian dynamics

A LUSAS model that is used to determine natural frequencies for the simple criterion in EN1990 clause A2.4.3.2(2) can be easily updated to include dynamic actions. Nonlinear behaviour (such as tensioning-stiffening associated with the use of cables) can also be incorporated. 

The LUSAS pedestrian load wizard creates the necessary moving and varying-magnitude load, based on input such as the recommended Bridge class (NA to EN1991-2, Table NA.7). Its use:

  • Simplifies and automates pedestrian load generation

  • Generates all loadcases to model the passage of pedestrian groups

  • Provides results that can be printed, exported to spreadsheets, or graphed 

Pedestrian types (walking or joging/running) control the reference load and speed of the moving pulsating load representing the pedestrian or pedestrian group. Both forward and reverse moving loading is possible. Graphs of loading can be automatically created.

Results can be printed and exported to spreadsheets or graphed using standard graphing facilities to assess, for example, the acceleration or displacement at a selected node against time.

Pedestrian Load Wizard


Vehicle load optimisation in general

Country design codes currently supported by the Vehicle Load Optimisation software option include:

  • Australia AS5100-2:2004

  • AUSTROADS standard

  • Canada CAN/CSA-S6-06

  • China JTG D60-2004 and HK

  • Eurocode EN1991-2 incorporating the National Annexes of UK, Ireland, Italy, Poland and Sweden.

  • Finland Highway Loading standard.

  • India IRC6:2000 and IRS: CBC-1997

  • Korea Highway Loading standard.

  • Malaysia JKR Highway Loading standard.

  • Norway Highway Loading standard.

  • South Africa TMH7

  • Sweden BRO standard

  • Transit New Zealand Bridge Manual (SP/M/022 2nd Edition)

  • UK Highways Agency Departmental Standard BD21/97, BD21/01, BD37/88 and BD37/01

  • USA AASHTO LFD and LRFD standard

See Vehicle Load Optimisation for more details

Steel and Composite deck design

The Steel and Composite Deck Designer software option enables design checking of multiple sections on steel and composite bridge decks to the Eurocodes, allowing otherwise time-consuming and error-prone manual design calculations to be carried out efficiently. 

  • Force and moment results for selected bridge deck elements are provided by LUSAS and loadcase combinations, defined within LUSAS, are associated with design limit states and phases defined in the Steel and Composite Deck Designer.

Within the Deck Designer:

  • Design calculations covering ULS bending, stress, shear and interaction; SLS stress, web breathing and cracking, and fatigue checks for main members and connectors are carried out rapidly. 

  • Multiple sections with different properties (haunches, stiffeners, etc) can be considered. 

  • Results, output in tabbed dialogs, visually show values that pass or fail. 

  • Graphs and a report containing all input data and output with references to the Eurocode clauses can be easily created.

See Steel and Composite Deck Designer for more information.

Slab design

The LUSAS RC Slab Designer is for use with reinforced concrete slabs (without prestressing) that are modelled using plate or shell elements. It enables contours and values that indicate flexural reinforcement requirements at Ultimate Limit State (ULS) to be plotted, and plots design crack widths at Serviceability Limit State (SLS) for those design codes that support this. Codes currently supported include:


  • AS5100-5-2004

  • AS3600-2009

  • BS5400-4, BS8007 and BS8110

  • CAN/CSA S6-06

  • Eurocode EN1992-1-1 and EN1992-2

  • IRC: 112-2011 and CBC-1997

  • SS CP65: Part 1 and 2: 1999


Prestress and post tensioning

Tendon forces are calculated in accordance with:


  • Eurocode

  • China

See Load types and combinations for more information.


Concrete creep and shrinkage

Concrete creep and shrinkage is calculated in accordance with:

  • CEB-FIP Model Code 1990

  • Eurocode 2

  • Chinese model codes (creep only)

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Software Information

  Bridge / Bridge plus
green_arrow.gif (94 bytes) Software overview
green_arrow.gif (94 bytes) Modelling in general
green_arrow.gif (94 bytes) Advanced elements, materials and solvers
green_arrow.gif (94 bytes) Load types and combinations
green_arrow.gif (94 bytes) Staged construction modelling
green_arrow.gif (94 bytes) Geotechnical / Soil-structure modelling
green_arrow.gif (94 bytes) Analysis and design
green_arrow.gif (94 bytes) Design code facilities
green_arrow.gif (94 bytes) Viewing results
green_arrow.gif (94 bytes) Software customisation

  Bridge LT
green_arrow.gif (94 bytes) Software overview

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  Choosing Software
green_arrow.gif (94 bytes) Software products
green_arrow.gif (94 bytes) LUSAS Bridge LT
green_arrow.gif (94 bytes) LUSAS Bridge
green_arrow.gif (94 bytes) LUSAS Bridge Plus
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  Software Options
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  Case Studies
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  Additional Information
green_arrow.gif (94 bytes) Linear and nonlinear buckling analysis
green_arrow.gif (94 bytes) Curved girder analysis
green_arrow.gif (94 bytes) Integral or jointless bridges
green_arrow.gif (94 bytes) Post-tensioning
green_arrow.gif (94 bytes) Concrete modelling
green_arrow.gif (94 bytes) Interactive Modal Dynamics
green_arrow.gif (94 bytes) LUSAS Programmable Interface (LPI)

  General information
green_arrow.gif (94 bytes) Hardware specification
green_arrow.gif (94 bytes) Licencing and Networking options
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green_arrow.gif (94 bytes) Documentation
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Any modelling and analysis capabilities described on this page are dependent upon the LUSAS software product and version in use.