Software for the analysis and design of composite road and railway bridges (two-girder and box bridges)

Mixte Bridge is an advanced software application for the design according to Eurocodes and French regulations of composite road and railway two-girder or box bridges. It has been distributed to the European market since 1997 (initial version had French design regulations) and has been used for the design of hundreds of road and rail bridges.

Mixte Bridge allows the analysis and design of composite bridges with multiple spans. A linear beam model is constructed and the traffic loads are automatically determined according to Eurocode regulations. The internal forces and stresses are then calculated and all the necessary checks are performed. The calculations report is automatically generated.

Mixte Bridge is developed by Conception Consulting Engineering Solutions (CCES).

Mixte Bridge was initially developed by CCES and CTICM (Centre Technique Industriel de la Construction Metallique) of France and incorporated a broad area of expertise in composite bridges.

Mixte Bridge is the result of the high level of expertise and experience of CCES engineers in the composite bridges domain. CCES software is being used by organizations such as the design department of the French railways (SNCF), Design Offices, and Construction Companies such as Eiffage Métal and Baudin Chateauneuf.

In general:

  • A beam element model for the simulation of the bridge structure is used.
  • The analysis is based on the longitudinal bending (displacements of the axis of the bridge) for one of two cross section beams (the most unfavorable).
  • Issues related to the cross section of the bridge are automatically handled (partition of loads for the two girders).
  • Interface: English, French.


  • Automatic calculation of effective widths at all positions.
  • Automatic calculation of equivalent factors according to the load type and the concreting day.
  • Automatic creation of reglementary loads and combinations (SLS, ULS).
  • Global analysis considering the concrete cracking.
  • Sections classification and reduced section characteristics.
  • SLS and ULS design checks of the composite section taking into account the concrete cracking and the moment-stresses redistribution.
  • Fatigue verifications.
  • Verification of the web panel stability and stiffeners (horizontal and vertical).
  • Calculation and verification of the shear connectors.
  • Verification of the welds.
  • Eigen values calculation of the composite beam.
  • Influence lines.
  • Calculation of precamber and reactions.

Structural data:

An efficient graphical user interface is used for the basic data input as described below:

  • Structure topology definition (geometry) for automatic node generation of the linear beam model.
  • Material mechanical properties definition.
  • Sections geometrical characteristics definition for I shaped built-up sections with automatic calculation of their mechanical characteristics for all stages.
  • Tapered sections with linear and parabolic height variation are also included as well as selection among standard catalogue profiles.
  • Detailed concreting phases definition.
  • Definition of traffic and train loads.
  • Automatic generation of load combinations and envelops.

Flange treatment:

Shear lag effect

  • Global analysis.
  • SLS combinations and fatigue.
  • ULS combinations (tension, compression).


  • Plate buckling of elementary sub-panels.
  • Global buckling of the flange.

Shear verification

  • Shear stress check in the global stiffened flange.
  • Shear stress check in each sub-panel of the flange.
  • Interaction M-V.

Longitudinal stiffeners

  • Axial Rigidity δ.
  • Flexural Rigidity γ.
  • Torsional Rigidity θ.
  • Buckling.

French regulations:

A module for the application of French regulations, based on Fascicule 6, Titre II and Titre V, Circulaire 81-63, SNCF-Livret 2.01, is available.


Module for the design according to Eurocodes and French regulations of composite road and railway two-girder bridges.

Module for the design according to Eurocodes of composite road and railway box bridges

Module for the design according to Eurocodes of composite road and railway bridges.  The internal forces under reglementary loads for the most unfavorable girder, calculated by any structural analysis software, are the data input of the software. Mixte Verif provides the capability to perform the calculation of internal forces for particular loads as shrinkage and temperature or other.

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+30 210 2209383

15 Mesogeion Avenue, Athens, 11526

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