Load optimisation and combinations

Traffic Load Optimisation and Combinations

The LUSAS Vehicle Load Optimisation (VLO) and Rail Load Optimisation (RLO) software options extend the static and moving vehicle loading capabilities of LUSAS Bridge. 


Automated load combinations speed-up the development of load combinations for supported codes of practice.

New in Version 21

  • Traffic loading effects for any results of interest: moments, shears, torsions, stresses.
  • One envelope covering all of your structure. No nodes to choose, no loadcases to solve, no comparisons to make.  Combine the one envelope with dead loads and other loads for design effects everywhere.
  • Rationalised vehicle placement methods produce results faster.

Vehicle load optimisation

Speed the calculation of vehicle load patterns

Obtain critical highway vehicle loading patterns on bridges to many international codes of practice and apply these loading patterns to LUSAS models. 


Apply loads to any structural system from simple beam and grillage models to shells and volumes.


Greatly simplifies the evaluation of worst load position, reduces the amount of time spent generating models, and leads to more efficient and economic design, assessment or load rating of bridge structures.

How it's done - for locations of interest

User specified locations of interest can be evaluated, or whole structure results may be obtained.

1. Define kerb lines representing the extent of the carriageway. Specify one or more locations to be used for a loading evaluation and assign influence attributes.
2. An influence surface for each position is automatically calculated (using a Direct or a Reciprocal Method) and can be optionally displayed.
3. The vehicle load optimisation facility interrogates each influence surface and calculates the critical loading pattern, which  can be optionally displayed prior to calculating loading effects.
4. Critical loading patterns are used to calculate the loading effects on the model. Loading patterns can be optionally superimposed too.
The following highway design codes are currently supported:
  • Australia: AS5100-2: 2004, AS5100-7: 2004 (Austroads)
  • Canada CAN/CSA-S6-06 (Design)
  • China: JTG D62-2015
  • Denmark: DS/EN 1991:2 DK NA:2015
  • Europe: EN1991-2 Recommended values
  • Finland: LO 24/2014
  • India - IRC:6-2017
  • Ireland: EN1991-2
  • Italy: EN1991-2
  • New Zealand (Transit New Zealand Bridge Manual)
  • Norway: NS EN1991-2.2004 NA 2010 + NA-rundsskiv 07-2015
  • Poland: EN1991-2
  • Saudi Arabia: MOMRA Bridges Design Specifications
  • Sweden: EN1991-2 (2009), EN1991-2 (2011), TDOK 2013:0267 Version 3.0
  • South Africa: TMH7
  • United Kingdom: EN1991-2, BA34/90, BD21/01 including Annexes D and E, BD37/01 (Road+Rail), BD86/11, BS5400 Rail Railtrack document RT/CE/025, CS 454 Assessment of Highway Structures and Bridges, and CS 458 rev 0 with ALL Model 1. 
  • United States of America: AASHTO LRFD (7th and 6th Edition), AASHTO Standard Specifications (17th Edition, and AASHTO MBE Section 6A (LRFR). 

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Whole structure results

Obtain traffic loading effects for any results of interest: moments, shears, torsions, stresses - anywhere on your structure. One envelope covering all of your structure. No locations of interest to specify, no loadcases to solve, no comparisons to make. 


Combine the one envelope with dead loads and other loads for design effects everywhere. (Version 21.0)

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Influence analysis and enhanced traffic load optimisation

Understand key aspects of influence analysis, then watch how influence analysis can now also be carried out at beam/shell slice resultant locations and used in a vehicle load optimisation analysis to derive corresponding traffic loading positions on the bridge deck. (Version 19.0)


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New bridge assessment loading codes in Version 19.1

The Vehicle Load Optimisation facility has been extended to support optimised loading and custom vehicles for United Kingdom CS 458 rev 0 with ALL Model 1 and United States of America AASHTO MBE Section 6A (LRFR) (Version 19.1)


Rail load optimisation

Generate the most critical rail loading pattern for a selected track layout, for each influence shape under consideration. 
Design codes currently supported:

Tracks and track layouts

  • Define individual track layouts to specify particular track loading scenarios 
  • Define segments of track by coordinate input, from spreadsheet data, or from selected lines and arcs drawn to represent track centrelines in the LUSAS model. 
  • Specify minimum radii of intersecting tracks
  • Visualise individual track layouts on the model.

Direct Method Influence Analysis for Rail use

View influence shapes that follow the alignment of each rail track.

View results on model

View contour and value results from loading.

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Rail Load Optimisation

Watch this short video to see how to carry out a train/rail load optimisation analysis on a two-span box beam bridge that is modelled using shell elements.

Tracks, including a crossover and a signal stop location, are defined and visualised, and after running an influence analysis, critical rail loading patterns for a chosen design code are obtained for selected track arrangements. (Version 18.0)


Automated load combinations

Faster combination building

Speed the development of load combinations with automation according to codes of practice.


Apply to buildings, bridges, foundations and other infrastructure.Apply these to buildings, bridges, foundations and other infrastructure.

Intelligence in load types

Tag each loadcase with a type according to supported international codes.

Allow the wizard to produce load combinations which consider all applicable permutations of variable actions and permanent loads.

Flexibility

Edit factors from the Code of Practice to suit project needs. 

Use advanced options to specify the mutual exclusivity of loadcases within a selected load type. 

Understand the factoring of all combinations and envelopes easily and visually.

Supported codes of practice

  • Australia - AS/NZS 1170 
  • Canada - CSA-S6-14 
  • China - JTG D60-2004 
  • Europe - EN1990 Buildings - National Annexes for Finland, Ireland, Italy, Norway, Recommended Values , Sweden, UK.
  • Europe - EN1990 (Footbridges) -  National Annexes for Ireland, Italy, Recommended Values , UK.
  • Europe - EN1990 (Highway Bridges) - National Annexes for Ireland, Italy, Recommended Values , UK.
  • Europe EN1990 - EN1990 (Railway Bridges) - National Annexes for Ireland, Recommended Values , UK, 
  • India - IRC: 6-2017 
  • New Zealand - AS/NZS 1170 
  • United Kingdom - BD21/01, BD37/01 , CS 454 , GB 50009 - 2012 
  • United States of America  - AASHTO 7th Edition, 8th Edition 
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