Dear colleagues and friends of ATENA software,

we would to share with you the news in our ATENA software and our plans for the coming year 2020.

ATENA brings the latest development in modelling and simulation of reinforced concrete structures to your desk. In the last years we have experienced a tremendous growth in terms of projects, number or employees and software sales. Currently we have 29 people working with us on ATENA development and consulting and research projects. This year we are experiencing a record revenue from software sales with yearly growth of about 37%.

In this newsletter, we would like to point out some of the most interesting and new features in ATENA software as well as give you an idea of our new development and the new ATENA features we are preparing for you. In this issue, we are focusing on the durability modelling features in ATENA, which were developed 2 years ago and have been further developed in the latest ATENA versions.

It became a tradition in our newsletter to share a success story how ATENA helped one of you to complete an interesting project or a paper.

In the last part of our newsletter, you can learn about the new technical papers on ATENA technology, and we would like to invite you to our training seminars in Prague as well as to the conferences next year, where we plan to participate with a scientific paper or ATENA exhibition. You are cordially welcome to meet us there, talk about your projects and see how ATENA can help you to better undestand the structures you are working on.

We look forward to cooperating with you or seeing you somewhere around the globe. The world seems to be surprisingly small sometimes :-).

With best regards from Prague

Your ATENA team

ATENA in the cloud
In the past year, the ATENA cloud has been further improved and developed. It provides two main functionalities:

(1)    it can be used to execute all ATENA software tools on-line using a dedicated computer on the Google cloud. Free temporary account is available to first time ATENA users for testing and evaluating the software. Just go to “atenacloud/cervenka.cz” to obtain a free account and test the unique ATENA reinforced concrete simulation software.
(2)    it can be also used for running large scale analysis by renting a computer with larger memory capacity or higher speed.

Fig. 1: Example of ATENA analysis on the cloud

Fig. 2: Application of ATENA durability model for the corrosion and service life analysis of a cantilevered bridge structure

(3)    the third application is for running parametric studies or probabilistic simulations from SARA Studio. In this case, a user can submit a zip file containing several ATENA input files generated by SARA Studio or other application. A dedicated virtual computer is created for each analysis, and the nonlinear analysis by ATENA is executed remotely. In this way all necessary analyses can be run simultaneously with huge time savings.

Models for durability and reinforcement corrosion

The durability feature has been further improved and developed. ATENA can be used to evaluate the durability of reinforced concrete structures during its service life. In this durability model, the environmental conditions can be specified as a new boundary condition. This typically includes chloride concentration, CO2 content or relative humidity. Based on this information and the distance of reinforcement to this surface, the chloride or carbonation propagation is calculated in time taking into account the possible presence of cracks. When the propagation front reaches reinforcement, the corrosion model is activated, which results in the reduction of reinforcement area. This effect can be included in any reliability or strength assessment in ATENA calculation as shown for instance in Fig. 2.

Durability modeling - Alkali-silica-reaction in concrete
Alkali-silica reaction (ASR) is a reaction in concrete between alkali hydroxides and reactive siliceous aggregates. This process causes the development of expansion strain in concrete, which may cause secondary cracking and can significantly reduce the concrete strength. ATENA models now cover the most important aspects of durability of reinforced concrete structures such as chloride and carbonation process, reinforcement corrosion and ASR. The durability features are all available since version 5.7, and were developed in the DURACERV funded by Czech Technological Agency under the project #TA04031458.

Construction process modelling

This functionality has been further developed and improved. It can be used to simulate geotechnical problems (Fig. 3.), bridge construction or general repair or strengthening approaches.

Fig. 3: Construction process modelling from GeoProduction 4.0 project

Fig. 4: Evaluation of moment and shear force diagrams in a nonlinear analysis of continuous reinforced concrete beam

Improvements in the run-time and post-processor program ATENA Studio

ATENA Studio is one of the most popular tools in the ATENA simulation system. It allows runtime visualization of the analysis process as well as full post-processing capabilities even while the analysis is still running and the iterative process is not yet completed. This very useful insight into the iterative process helps to discover any modeling errors and gives useful hints how to eliminate any divergence problems. One of the most useful features for engineers is also the possibility to evaluate the distribution of the classical engineering quantities such as moments or shear forces as shown in the example in Fig. 4.

Material driver

This new software tool can be used to test the behavior of individual material models in ATENA or for testing and debugging user defined material models. This tool allows to test the behavior of ATENA compatible material models under arbitrary loading paths. It support loading by both strain or stress increments or any combination thereof. The resulting stress-strain curves are plotted in 2D graphs thus allowing clear and easy verification or understanding of the model behavior. The program also provides the actual values of any state variables associated with the tested material. Currently the driver supports only material models for stress analysis.

Fig. 5: Screen shot of the new ATENA material driver for testing and understanding of material models

Structural assessment of bridge columns with engineered cementitious composites and Cu-Al-Mn superelastic alloys

F. Hosseini, B. Gencturk, S. Lahpour and D. Ibague Gil
Department of Civil and Environmental Engineering, University of Houston, TX, USA

The experimental work was about enhancing damage tolerance of bridge columns using high performance materials. A new design concept was introduced using engineered contentious composite (ECC) and superelastic alloys and the specimens were tested under incremental cyclic loads. It was found that the design concept successfully can reduce the permanent deformation in bridge columns and enhance their damage tolerance. Following the experimental work, the tested specimens were modeled in ATENA.

Fig. 6: Boundary conditions, loading and meshing

Fig. 7: Comparison of experimental and computational load-deformation diagrams: (C) HFA-Tube, (D) HFA-Tube-SEA

One dimensional constitutive model was added to the material library of ATENA to simulate behavior of the superelastic alloys. Additionally, behavior of ECC simulated by introducing smeared reinforcement to concrete with adjusted stress-strain curves. The numerical models successfully predicted the experimental results and the modeling approach was used to develop a parametric study which is scope of another paper.

Functional POROus cementitious nanocomposites for heat storage in buildings using Phase Change Materials

Project in cooperation with The University of Tokyo, Technischen Universität Darmstadt, National Institute of Material Science, Spanish National Research Council-Centre for Materials Physics, GrapheneTech and Röser Ingenieurbeton.

Fig. 8: Schematic impression of the functional PoroPCM nanocomposite for energy efficient and heat adaptive wall applications

Fig. 9: Indicative simulation of PoroPCM versus a general EPS insulation layer

Developing a multifunctional Phase Change Materials modified porous cementitious nanocomposite (PoroPCM) that can be used for storing large amounts of heat energy in the insulation layer of buildings is the main aim of joint synergetic Japan-EU consortium. With this project, partners have the ambition to develop an innovative functional material that combines high conductivity, high insulation capabilities, and high storage capacities within one highly porous cementitious system.

The proposed smart technology will encompass a multiscale experimental and numerical approach which covers advanced nanotechnology-based solutions to a full-scale demonstration project. The consortium partners, consisting of excellent universities, research institutes and ambitious SME companies, have the strong ambition to build this new technology in a joint international framework while supporting sustainable and multilateral research cooperation and promoting transnational mobilities between Japan and the European partners through:

• Joint development of the PoroPCM solution with all consortium partners;
• Joint research and workshops in both Japan and EU;
• Full-scale demonstration of the PoroPCM product by monitoring its thermal performance.

New knowledge and partnerships among the consortium partners will be used for future exchange of students and to enhance the mobilities of researchers with the aim to develop new research initiatives. The PoroPCM project will create 17 deliverables reporting the activities and research results of all partners involved, as well as a full-scale demonstration wall, which will provide a basis for further joint research.

Advanced system for monitoring, diagnosis and reliability assessment of large-scale concrete infrastructures

Project in cooperation with Brno University of Technology, Czech Republic; Jiangsu Donghua Testing Technology Co.,Ltd and Hohai University, People´s Republic of China.

The aim of the project is to develop a new bridge/infrastructure assessment software system that will allow to assess performance, reliability and damage based on health monitoring, data-driven approaches and system identification on the level of cracks propagation and hence considerably improve prognosis of bridges reliability. We will deliver an integrated software system both as a product and as a consulting service.

Fig. 10: Simulation of truck crossing a pre-damaged bridge, see also video

System will be based on computational nonlinear modelling of structures and will include extending modulus for: sensitivity analysis, fractal-based damage assessment procedure based on cracks pattern evaluation in concrete structures, surrogate modelling based on polynomial chaos expansion, dynamic damage identification, reliability and degradation modelling.

FiberLab

Partners: Červenka Consulting, s.r.o. & JKP Static Ltd.

The project developed a software tool to support the design of advanced structures or products from fiber reinforced concrete (FRC) using simulation prototyping based on the existing product ATENA. The project developed a separate module of this system specifically targeted for fibre reinforced concrete industry. The product shall also support parametric modeling and embedded scripting language to enable the fast development of even more specialized design tools for the development and design of specific construction products for pre-cast industry or other mass production.

Fig. 11: Parametric modelling in the new ATENA Studio Pre-processor developed by FibreLAB project

Fig. 12: Parametric model of tramline on a viaduct calculation with ATENA

Fig. 13: Running analysis and visualization of cracks in ATENA Studio

Dear users of ATENA software,

we would like to invite you to our ATENA Advanced User Seminar 2020. The seminar will take place in Prague, the Czech Republic on February 10-12 in Czech language and June 10-12, 2020 in English language.


In 2016 the content of the seminar was rearranged compared to the previous years. We decided to concentrate on fewer topics, but provide deeper coverage and more hands-on experience with particular problems. Based on the feedback from our hotline support, we selected several topics, where we expect that ATENA users could benefit most from more in-depth explanation or background information:

• Overview of new ATENA version 5.7.
• Modeling contact problems in ATENA.
• Modeling strengthening of reinforced concrete structures.
• Modeling of construction process in ATENA for bridges and tunnels.
• Modeling of fiber-reinforced concrete structures.

November 20-21, 2019
Concrete Days 2019
Hradec Králové, Czech Republic
Event website

March 9-10, 2020
Dresdner Brückenbausymposium 2020
Dresden, Germany
Event website

March 23-24, 2020
14. Fachtagung Baustatik – Baupraxis
Stuttgart, Germany
Event website

March 29 - April 2, 2020
ACI Spring
Rosemont/Chicago, USA
Event website

April 23-24, 2020
Baukongress 2020, Construction Congress
Vienna, Austria
Event website

AL-SAOUDI, A.a, AL-MAHAIDI, R.,  KALFAT, R.,  CERVENKA, J.: Finite element investigation of the fatigue performance of FRP laminates bonded to concrete (Article), Composite Structures, Volume 208, Elsevier, 15 January 2019, Pages 322-337,  ISSN: 02638223, DOI: 10.1016/j.compstruct.2018.10.001

CERVENKA, J., AL-SAUDI A., PRYL, D., Modelling of High-cycle Fatigue Crack Growth in Concrete, 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures FraMCoS-X, June G. Pijaudier-Cabot, P. Grassl and C. La Borderie  (Eds), DOI: 10.21012/FC10.236385

CERVENKA, J., CERVENKA, V., Model Uncertainties and Global Safety Formats for Reinforced Concrete Design by Numerical Simulation, NAFEMS World Congress 2019, June 17-20, Quebec City, Canada

JENDELE, L., CERVENKA, J., VAITOVA, M., FEM modelling of digitally printed concrete structures using 3D extrusion, The Seventh International Conference on Structural Engineering, Mechanics and Computation (SEMC 2019), Sept. 2-4, Cape Town, South Africa

SYKORA, M.,  CERVENKA, J., CERVENKA, V., MLCOCH, J., NOVAK, D., NOVAK, L., Pilot comparison of safety formats for reliability assessment of RC structures, Proceedings of the fib Symposium 2019: Concrete - Innovations in Materials, Design and Structures 2019, P. 2076-2083, Krakow; Poland; 27-29 May 2019; Code 147831, ISBN: 978-294064300-4, eid=2-s2.0-85066066064

VAITOVA, M., JENDELE, L., CERVENKA, J.: 3D printing of concrete structures modelled by FEM, 26th Concrete Days 2019, November 20-21, Hradec Kralove, Czech Republic

VAITOVA, M., JENDELE, L., CERVENKA, J.: Digital 3D printing of concrete structures using FEM, The Sixteenth International Conference on Civil, Structural & Environmental Engineering Computing, September 16-19 2019, Riva del Garda, Italy