Dear Friends of ATENA,

we are approaching you with a 2024 Fall newsletter. We wanted to provide more detailed information on the planned release of ATENA 2025, therefore our fall newsletter is reaching you close to the end of the year. This year, we were very proud to release ATENA 2024, the first ATENA version with the new generation of the 3D pre-processor that replaces the former ATENA 2D and 3D Engineering GUI. This new pre-processor has finally unified the 2D and 3D capabilities into one easy-to-use pre-processor. We believe you are appreciating these enhancements. We have been trying to make your daily work routine easier, more friendly and comfortable. 

Let's move on now to introduce our plans for the upcoming year!

Most importantly, ATENA 2025 will be released next year. We have already been working on it. This will be a big milestone in our company history as some of the dynamic features will finally be incorporated in this new version such as transport (heat, hydration, thermal and fire analysis). ATENA 2025 will be a well-enhanced ATENA 3D Engineering with some new features exported from ATENA Science. We believe you will enjoy this new version and have fun with it!

After a short summer break, we decided to return back to tradition of organizing webinars. Each of the webinar will be covering a selected topic. Our existing as well as potential customers are welcome to take part. You can also ask questions during each session.

We are eager to host another seminar in Prague in 2025 as we received a lot of positive feedback from our customers who had a chance to attend it in person. 

With best regards from Prague and have a great remaining part of 2024!

Your ATENA team

Throughout the year we have released several updates of ATENA 2024. The latest update was released on November 11th including mainly various improvements and problem corrections.

ATENA 2024l is available for download to all users with valid maintenance license till October 22nd, 2024. This update introduces an enhanced Python scripting feature, significantly expanding customization capabilities. Comprehensive examples of user-defined Python functions, including full ATENA scripting integration, can be found in the updated ATENA documentation. Performance improvements include faster geometry collapsing, resolved issues with deleting polycurves, and the creation of non-planar surfaces. 

Fig. 1: ATENA 2025 allows the development of user defined modules for specialized structures, like this Python module for concrete hydration heat analysis for typical concrete block arrangements.

Fig. 2: Hydration heat analysis development in a typical structural arrangement generated by a used defined specialized Python module.

For analysis enhancements, the .bat file is now saved alongside the INP file, with additional .msg, .out, and .err arguments included for task execution within the .bat file.

Bug fixes address multiple aspects: layer duplication during imports has been resolved, and scripts now support new layers and combined materials in 2D. Additionally, INP file corrections include updates to load case IDs, contact fixes, Arc-length parameter adjustments, spring materials, load force boundary conditions, and NURBS surface handling.

New development ATENA 2025:

At the beginning of 2025 we will release a major upgrade of our ATENA simulation system. 

The main improvement will be in the development of the new Engineering preprocessor. Our main goal is unite our two ATENA products: Engineering and Science into a single user friendly and comfortable environment covering all your needs for the realistic simulation and modelling of reinforced concrete structures. See the list below of the major new developments.

ATENA 2025 Engineering Preprocessor:

- new support for thermal and moisture analysis enables to simulate the hydration of your concrete and its impact on potential crack development as well as for instance high temperature fire loading on reinforced concrete structures.

Fig. 3: ATENA 2025 supports IFC import such as this beam element with stirrups.

Fig. 4: Modelling of a complex segmental prestressed concrete bridge with detailed arrangement of normal reinforcement in the new ATENA Engineering preprocessor available in ATENA versions 2024 and 2025.

- improved BIM support by importing ifc files.

- improved and enhanced Python scripting support. It is possible to develop user defined methods for the complete model development for specialized structural elements or problems. See Fig. 2 showing a specialized interface for simplified modelling of temperature development during concrete hydration.

- automatic identification of interface elements make it much easier to develop complex models with internal contacts and interfaces.

- plus miscellaneous improvements and corrections in stability and user friendliness.

ATENA Studio & FE analysis core system:

- visualization of true shape of 1D beam and 2D shell elements.

- new quadrilateral spring elements make it easier to model flexible planar support.

- export of internal force diagrams into automated report generation feature as well as to csv files for further postprocessing in Excell.

Beta version of the new ATENA 2025 is available for testing, and can be downloaded from the downloads section on our website.

Fig. 5: ATENA version 2025 supports the full visualization of the 3D geometry of 1D beam elements both in the pre- as well as in the post-processor for the realistic visualization of engineering quantities on 1D beam and 2D shell elements..

ATENA's Success in the Blind Prediction Contest

We are thrilled to announce ATENA's outstanding performance in the blind prediction contest on the strength of a concrete pre-stressed T-beam. The contest was held during the nonlinear modeling seminar in Wildegg, Switzerland, organized by Bau und Wissen and Dr. Alex Kagermanov. ATENA delivered the most accurate strength prediction of 975 kN, closely matching the test result of 906 kN obtained by P. Huber from TU-Wien. This result highlights ATENA’s precision and reliability in structural analysis.
We also commend the excellent predictions from other participants, including Hammad E. Jist and Phillipe Menetrey (INGPHI SA), as well as Moritz Meyer and Arthur Probsting (Schmidt & Partner Bauing AG), all of which fell well within the expected material uncertainty.

Fig. 6: Presentation of the blind competition results at NLFM Seminar in Wildegg, Switzerland by Alex Kagermanov.

Fig. 7: Special issue of the Buildings Journal on Advanced Simulations, we are looking for contributors with original papers on this exciting topic.

Buildings - Special Issue

For the Special Issue of Concrete in the Digital Age: Advanced Simulations for Structural Innovation we seek high-quality original research articles focused on the latest techniques and methodologies in the analysis, design, and simulation of concrete structures, particularly leveraging ATENA simulation tools and software. We welcome contributions from theoretical explorations and practical applications that meet high technical standards, promoting a cross-disciplinary approach that can spur innovation across various fields.

More details can be found HERE. 

Post-damage recovery of substandard RC columns by CFRPs

Authors: Ozgür Yurdakul, Petr Vnenk, Ladislav Routil, Bohumil Culek, Ozgür Avsar
Engineering Structures, Volume 306, 1 May 2024, 117806, https://doi.org/10.1016/j.engstruct.2024.117806

Cyclic response of substandard reinforced concrete (RC) columns and structural repair of pre-damaged columns by carbon-fiber-reinforced polymers (CFRPs) were investigated through combination of experimental and advanced numerical modeling methods.

The specimens, representing typical RC columns in substandard buildings, were constructed from low-strength concrete, plain round bars, and nonconforming reinforcement details.

The key parameters under investigation included the lap-splice, hook detail in the longitudinal reinforcement, and axial load ratio.

The crack patterns and capacities observed in the numerical solutions align with the responses observed in the experimental tests.

Fig. 8: Damage evaluation in as-built specimens.

Fig. 9: Stress distribution and crack pattern from FEA.

Seismic Modelling of Corroded Reinforced Concrete Columns

Authors: Nicolas El-Joukhadar, Farah Dameh, Stavroula Pantazopoulou
Engineering Structures, Volume 275 (2023), 115251, https://doi.org/10.1016/j.engstruct.2022.115251

Deterioration of seismic resistance of columns due to existing corrosion damage is investigated using advanced
non-linear finite element simulation and analysis of a large database of tests with the objective to develop
performance criteria for seismic evaluation and assessment. 

Current guidelines for structural seismic evaluation do not address how to account for the condition of the reinforcement. Incorporating the degree of bar corrosion in the evaluation procedures would complicate significantly the problem of seismic assessment.

However, bar section loss, embrittlement, loss of material strength and interfacial bond, all affect the member’s residual mechanical properties, the hierarchy of failure modes and the consequences on seismic performance of complete structural components.

In this work, simple modifications of existing nonlinear assessment procedures are proposed, in order to account for the effects of corrosion on seismic performance.

Reduction factors of reinforcement stress–strain properties and column stiffness, strength and deformation capacity were calibrated to an assembled database of experimentally tested corroded columns, and were verified through advanced nonlinear finite element analysis, after modeling the effect of mass loss on material properties.

Fig.10: Hysteretic responses of the finite element analysis plotted over the hysteretic response of experimentally tested columns reported by Goksu & Ilki.

ATENA Webinar September I/2024
The webinar was focused on the basic operation and usage of the new ATENA 2024 preprocessor. It is based on our standard tutorial example: Shear Wall with Round Opening.

ATENA Webinar October II/2024
The Tips and tricks in GiD preprocessing was discussed and presented on an example of grouted connection and modelling of shear stud connections in composite steel/concrete beams in this webinar:
- Useful tips and tricks for complex model development in GiD.
- Creating and defining contacts volumes/interfaces in complex models.
- Useful tips and tricks for the development of good finite element meshes in GiD.

Fig. 11: Introductory and detailed video is available on our youtube channel and should be studied before the webinar.

STF4SW - Sustainable Act for Construction Market: A new perspective on passive seismic protection

Partners:
University of Pardubice (UPCE) - Coordinator: Ing. Özgür Yurdakul, Ph.D., Czech Technical University in Prague (ČVUT), Červenka Consulting s.r.o. - Ing. Jan Červenka Ph.D., Kalekim Kimyevi Maddeler San. Ve Tic. A.Ş (KALEKIM), Technical University of Cluj-Napocav (TUCN)

Objective of the project:

The project aims to conduct extensive research on physical, chemical, mechanical, and acoustic properties of STF, specifically:
1) Generate advanced know-how for synthesis STF via polymerization of silanol and siloxane compounds.
2) Expanding literature with the synthesis of various boron-containing crosslinkers
3) Characterization of synthesized STF
4) Calibrating temporary/permanent crosslinks due to coordination number
5) Observation of crosslinked STF and filler interaction in hydro cluster, micro-fragmentation mechanisms (rheology profile)
6) Functionalization of additives for desired flow behavior
7) Mechanical tests on STF
8) Chemical resistance tests on STF (Interaction with possible contamination from soil)
9) Development of STF damper
10) Response of STF damper to seismic waves for field protection.
11) Numeric analysis of damper with STF for reaction to seismic wave
12) Simulation of field protection in various soil environments to understand the efficiency of STF damper

Fig. 12: Nonlinear simulation of dynamic seismic excitation of a 18 storey reinforced concrete building by ATENA.

Machine Learning for Multiscale Modelling of Spatial Variability and Fracture for Sustainable Concrete Structures (AI4FRACTURE)

Partners:
Cervenka Consulting, s.r.o.
Dep. of Structural Mechanics, Brno University of Technology,
Klokner's Institute, Czech Technical University in Prague

Fig. 13: Multiscale approach to fracture localization in reinforced concrete structures supported by AI based surrogate models.

AI4FRACTURE develops multiscale modelling methods for fracture initiation, development and localisation in RC structures. Improved fracture patterns and crack widths will be applied in the lifecycle assessment of structural durability and sustainability. Outcomes of AI4FRACTURE will help to overcome engineering issues when use of advanced probabilistic NLFEA for assessment of large RC structures is challenged. Proposed framework will provide new tools to overcome gaps in the existing knowledge and methods for RC fracture modelling and reliability assessment, utilising the most advanced theoretical tools and available experiments. 

March 19-20, 2025
Brueckenbausymposium
Dresden, Germany
Event website

March 22-28, 2025
RILEM 2025 Spring Convention
Mendrisio, Switzerland
Event website

March 22-25, 2025
FraMCoS XII conference
Vienna, Austria
Event website

March 24-25, 2025
Bridges
Brno, Czech Republic
Event website

March 30 - April 2, 2025
ACI Spring Concrete Convention
Toronto, Ontario, Canada
Event website

April 9-11, 2025
Structures Congress
Phoenix, Arizona, USA
Event website

October 26-29, 2025
ACI Fall Concrete Convention
Baltimore, MD, USA
Event website

Fig. 14: Gabriel Meždej from BlueberryS s.r.o. and Martin Berka during the Bridges Conference 2024, Czech Republic.

CERVENKA, J., Application of Eurocode 2 new safety formats for nonlinear analysis in design and assessment of concrete structures, Nichtlineare FE-Modelierung im konstruktiven Ingenierbau, Tagung, 14.11.2024, Wildegg, Switzerland

CERVENKA J., MARIK R., DRAHY V., RYMES J., JANDA Z., KOVAR J., AI Based Surrogate Model for Nonlinear Modelling of Reinforced Concrete, fib Symposium 2024, Nov. 11-13, 2024,Christchurch, New Zeeland

CERVENKA, J., MARIK, R., NOVAK, D., AI Based Surrogate Model for Digital Twins for Structural Health Monitoring, ACI Fall Convention, March 24-28, 2024, New Orleans, U.S.A., Special session on Comprehensive Essential Ingredients for Robust Data and Machine Learning-Driven Innovations and Analyses of RC Structures

CERVENKA J., RYMES J., JENDELE L., HERZFELDT M., Time dependent modelling and simulation of digital concrete, Concreep12 conference, June 5 –7, 20244, Delft University of Technology, Delft, The Netherlands

DAESCU A., C., GONZALEZ-LIBREROS J., WANG CH., CHÁVEZ A., A., KOVAR J., NILSSON L., LARSSON T., ELFGREN L., CERVENKA J., SAS G., Multilevel procedure for the demolition of a 65-year-old box girder prestressed concrete bridge in Northern Sweden, Structure and Infrastructure Engineering 

RYMES J., CERVENKA J., JENDELE L., BURES V., CITEK D., Integrating 3D Modelling and Non-linear Numerical Simulations in Concrete Additive Manufacturing, Nov. 11-13, 2024fib Symposium 2024, Christchurch, New Zeeland 

RYMES J., JENDELE L., CERVENKA J., Finite Element Modelling for 3D Concrete Printing: Framework and Examples, Central European Concrete Conference, Mikulov, Czech Republic, Sep. 22-24, 2024