ATENA 5.4 Release

Fig. 1: Design of TBM lining from FRC tubings for Ejpovice railway tunnel was supported by ATENA

Fig. 2: Crack development in the analysis of FRC tunnel
tubbing

New finite elements:

ATENA now supports also classical 1D beam and 2D shell elements (Fig 3 and 5). ATENA was always a specialized software for detailed reinforced concrete analysis. As such the emphasis was always on 2D/3D analysis using continuum based elements, which were enhanced by our specialized 3D beam and shell elements. ATENA users, however, want to apply nonlinear analysis to large scale structural problems, when classical beam and shell elements provide an efficient option.
They are formulated as fiber beam elements and layered shells that can be easily combined with full continuum based 2D/3D elements. In this way efficient models for large scale structures can be created, while preserving the option to model critical structural details with full continuum three-dimensional based models.

New features in ATENA Studio:

ATENA Studio is our unique software, where our users can immediately see how the structure responds to applied actions. Our unique run-time and post-processing system is now enhanced by the following features:
- Evolution diagrams of reinforcement quantities such as stresses, strains, etc (Fig. 4).
- Calculation and visualization of internal forces (see Fig. 6, i.e. moments, torsion or shear forces, for beam/shell elements as well as for continuum based elements. This greatly simplifies the application in design or assessment of existing structures
- User defined views and visualization parameters can be saved and shared among various ATENA Studio projects

     Fig. 3: Example of thermal load on RC frame building
     due to sun radiation and resulting slab cracking, slabs
     are modeled with shell elements

Fig. 4: Top - evolution of prestressing with losses, Bott.
- internal crack development and tendon stresses before failure

Fig. 5: Building model using 2D shell and 1D beam elements showing the moment development in the columns

Fig. 6: Concrete cracking above the main support,
moment evolution and deflection of a composite
steel-concrete bridge analyzed by ATENA

New modelling of pre-stressing losses:

The improved bond model enables very accurate and detailed modeling of pre-stressing losses due to friction and cohesion in tendon pipes as well as the subsequent tendon grouting with increased bond properties (see Fig. 4). Bond model can be activated in ATENA just by a single mouse click, no need for special interface elements or other complicated modeling tricks.

Loads at arbitrary locations:

Loads can be now applied at arbitrary locations, i.e. at point, lines or surfaces that do not need to be part of any geometric entity. This new feature greatly simplifies the application of complex loading patterns or moving loads.

New tutorials:

Several new tutorials have been developed and are available for download. They provide a step by step guidance in some of the typical ATENA application areas:
Tutorial for ATENA Science GiD FRC
- Analysis of fiber reinforced concrete structures, where one of the main problems the user typically need to solve is the proper definition of the fiber reinforced concrete material parameters. This process typically involves an inverse analysis of standard material tests. This process is in detail described in this tutorial with an application to segmental tunnel lining.
Tutorial for ATENA Science GiD Strengthening
- Strengthening by carbon fiber rods, lamellas or sheets is another application domain, where simulation with ATENA can be extremely useful. There are 4 possible approaches in ATENA for these problems, and this manual provides a step by step guidance and hands-on experience (Fig. 8).

     Fig. 7: Process of FRC material model parameter
     identification

Fig. 8: Failure of a model strengthened by FRP fabric