AnaDyn, software for dynamic and fatigue analysis of railway bridges

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AnaDyn

Software for dynamic and fatigue analysis of railway bridges

AnaDyn is used in the study of the dynamic behavior of bridges during the passage of high speed trains (TGV). The calculations and the verifications are based on Eurocodes (EN1991-2).

AnaDyn creates a wireframe spatial model that takes into account the effect of torsion due to the eccentricity of dynamic loads relative to the axis of the bridge and produces all the results and diagrams, needed for the creation of comprehensive reports.

AnaDyn creates automatically a report including all the verifications required by the Eurocodes, based on the values of the acceleration, the warping, the support rotations, the dynamic amplification factors, the bending moments-stresses for fatigue.

AnaDyn is developed and owned by Computer Control Systems S.A. (CCS).

AnaDyn is the outcome of the experience which the civil and software engineers of CCS have acquired from collaborating over the years with the French Railways (SNCF) in the field of dynamic behavior of bridges during the passage of trains. CCS software is being used by organizations such as the design department of the SNCF, Design Offices, and Construction Companies such as Eiffage Metal and Baudin Chateauneuf.

The extensive experience that CCS has accumulated in the field of structural dynamics, has led to the selection of the most effective analysis methodology. The calculations are performed quickly without any loss of accuracy. The wizard-based user interface is easy to use, while the automatic generation of the comprehensive reports and the built-in expertise facilitate the task of the engineer.

General:

The problem is treated in the linear domain.
The wireframe model is composed of beam elements with 3 degrees of freedom at each end (displacement Dy, rotation Rx, and rotation Rz).
Three models are automatically generated, one based on a low estimate of the mass, another based on a high estimate of the mass and one more for fatigue calculations using the average mass.
The critical velocities of passage are automatically calculated for each EC train.
The EC trains are processed automatically to history loads according to their passage velocities.
The dynamic analysis method is the modal superposition in the time domain.
The step for the integration of dynamic equations is proposed by the software.
A static calculation for each train (convoy type) is provided.

Structural data:

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

The topology of the structure is defined from the span lengths of the bridge, the distance between two tracks with respect to the axis of the bridge and the bias angles of the supports.
The sections are defined generically by their surface A, their bending inertia Iz and torsional inertia It.
The displacement and rotational masses are provided for each section and for two of the estimated cases of mass (mass low and high).
The software calculates the eigenmodes to be used in the dynamic analysis by allowing the user to make their own selection.
The selection of critical velocities is assisted by the automatic calculation of critical velocities over all selected modes and relevant trains.

AnaDyn can import special files from a Mixte 2I or Mixte Box project that define the topology of steps 1 to 3.

Results:

The results are displaying in tables and in diagrams.
The eigenmodes are displayed as diagrams.
For each train and each passage velocity the following results are displayed: maximum and minimum values of vertical displacements, rotations Rx and Rz, vertical accelerations and warping values.
The time variation of these quantities is presented in diagrams for the worst case.
For each train and each passage velocity, the values of the dynamic amplification factors at the midpoint of each of the spans, is displayed.
For the fatigue train and the two critical velocities, the time variation of the bending moment for the remarkable sections are displayed for the worst case.
The time variation of the bending moment diagram is shown for the worst case.