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Newsletter November 2015

New Release of ATENA Software

ATENA 5.3 Release

Dear ATENA friends,

this fall we are releasing the new version of ATENA, which brings you many new exciting features:

(a) improved robustness and validation of ATENA for seismic and dynamic analyses
(b) support for the new Austrian tunnelling method
(c) improved 3D beam elements for efficient modelling of large scale high rise building frames
(d) improvements in high-cycle fatigue model for concrete in tension
(e) support for parametric definitions in ATENA input/command file
(f) new extrude option enables pure brick meshes in extruded regions in ATENA 3D
(g) probabilistic module SARA/RLACS available also for ATENA Science
(h) plus many other improvements, corrections and bug fixes in ATENA 2D/3D, GiD Interface, ATENA Science and ATENA Studio.

(a) Improved robustness and validation of ATENA software for seismic and dynamic analyses. The dynamic capabilities of the new ATENA version has been tested to improve the program efficiency and robustness for analysing seismic problems. ATENA can be used now to perform static pushover analysis as well as subjecting the structure to the ground motion and evaluate its behaviour under this complex scenario using all available nonlinear models for concrete, masonry, steel or interfaces. The Fig.1 shows the program response in the two storey building experiment performed at ISPRA during the ESECMaSE project. See video here.

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Fig.1: Simulation of seismic experiment in ISPRA laboratories

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Fig.2: Simple example of tunnel construction process modelling in ATENA Science

 

(b) Support for the new Austrian tunnelling method is included in ATENA Science now. The user can define the activation or removal of parts the structural model to simulate the various construction cases. The redistribution of the forces between the removed parts and the new ones can be controlled through user defined parameters.

(c) Improved 3D beam elements increase the program efficiency in handling large scale models of multi-storey frame structures such as high rise buildings. The 3D beam elements can be used in combination with shell and/or solid elements to create efficient models for large scale analysis of frame structures. In the ideal approach, the bending elements are modelled using these special beam or plate/shell elements. The beam-column joints where shear failure mode can be expected should be modelled using solid elements. Similar modelling approach can be also used at the column-plate connections, where the punching failure mode should be verified by a finer model with solid elements (Fig. 3). The ATENA beam and shell elements can be easily combined with solid elements such that the most comprehensive, accurate and efficient approach could be use for checking your structures.

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Fig.3: Example of building analysis in new ATENA using the combination of the new 3D beam elements with 3D shell and solid elements

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Fig.4: Example fatigue analysis from project at Swinburne University of Technology by Mr. Atheer Al-Saoudi (Investigation of the Performance of FRP Anchorage Devices in RC Bridge Beams Subjected to Fatigue Loading)

(d) Improvements in ATENA fatigue model for effective simulation of high cycle fatigue of concrete in tension. This fatigue model has been further improved to increase its robustness. The basic idea of this model is to simulate the effect of high-cycle fatigue, but using only a limited number of cycles. The model of your structure is subjected to several load cycles. Each cycle effectively represents several hundred or thousands of cycles, and the corresponding damage is calculated based on this information. This unique approach enables efficient evaluation of the fatigue damage as well as the damage distribution during the loading process. Have a look for yourself at Fig.4, how this fatigue model was used to analyse the fatigue strength of a carbon fibre sheet connection to concrete.

 

 

(e) Parametric definitions are now supported in the input/command file. In the new version of ATENA, it is possible to introduce mathematical operations, define and assign values to variables. This can be effectively used for batch processing and parametric definition of the numerical models for various parametric studies. See Fig.5 for a glimpse of the new parametric input in ATENA command file.

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Fig.5: Example of parametric definition of material properties and structure geometry in ATENA input file

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Fig.6: The right part of the figure shows the hexahedral mesh using the new extrude option in ATENA v5.3, the left part shows the tetrahedral mesh in previous ATENA version

 

 

(f) Extrude meshing option in ATENA 3D. This very interesting new feature in ATENA 3D extends the type of macro-elements/regions for which brick elements (hexahedra) can be used. Any macro-element, which contains two opposite topologically identical surfaces, can be automatically meshed with brick (hexahedra) elements, which simplifies the modelling and increases the accuracy. Such macro-elements/regions are for instance typically created by the extrude operation (See Fig.6).

(g) Probabilistic module SARA/RLACS is available now also for ATENA Science. Any value in the ATENA  input/command file can be selected for randomization. The advanced probabilistic methods of FREET such as LHS, FORM, correlation matrix, simulated annealing can be used to perform accurate reliability prediction using the elite nonlinear models of ATENA. This totally new module is documented on the Fig.7 showing the full probabilistic evaluation of the design strength of a long-span (18 m) reinforced concrete girders with large openings.

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Fig.7: Load displacement diagrams obtained by calculations in program RLACS and ATENA

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Fig.8: Lognormal distribution for load capacities obtained by probabilistic study

The beta release of new ATENA version is available on our web page from October to all of our users with valid maintenance licence. The ATENA Update Check can be used to download the final ATENA v5.3 in few weeks. If your maintenance has expired please contact our sales representatives Martin Berka or Martina Placha for assistance.

ATENA Is the Winner!

Červenka Consulting is the winner of the contest among 66 participants from several continents

The prediction contest for the strength of four meters deep reinforced concrete slab strip.

University of Toronto team headed by Prof. Michael Collins and Prof. Evan Bentz are currently engaged at an experiment investigation of a large slab elements. With dimensions of the specimen, 4m deep and 21m span, it is the  largest shear test ever done.
Before testing, the data were distributed world wide, and more than sixty participants submitted their predictions. Vladimir Cervenka and his team predicted the failure loads as shown in Tab.1.
Červenka Consulting was declared as the winner of the contest among 66 participants from several continents.
Considering the uncertainties involved in a brittle type of concrete failure  the results are very satisfying. We believe that, more details will provided later based on data compiled  and distributed by the project organizers.

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Tab.1: Predicted failure loads of the slab elements

This prediction contest is another contribution to the long and steady effort of ATENA team in validation of ATENA software, its theoretical background and especially its constitutive models.
In this context, we would like to refer to a good record of Cervenka team in prediction competitions: Winner of “An international competition to predict the response of reinforced concrete panels”, Collins et al.,1982, Toronto. The best strength prediction in “RC Slab Shear Prediction Competition”, ETH Zurich, Jaeger and Marti, 2006.

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See video here.

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See video here.

ATENA Success Stories

Arch Bridge Nonlinear Analysis

Stephanie Franck, M.Sc.
Leipzig University of Applied Sciences, Germany

ATENA is used to simulate the failure of masonry arch bridges and to prove their structural safety under given live loads. In addition to the exact geometrical modelling of the bridges including the surrounding soil, the nonlinear 3D Finite Element analyses allow to simulate masonry cracking. As a result, comparatively realistic analysis models are obtained. The crack patterns in the simulations may directly be compared to those observed at the real structures. This allows to identify causes of damage and to evaluate the effects of strengthening measures. In the below-mentioned paper, it is demonstrated that different damage patterns of masonry arch bridges may be reproduced by nonlinear Finite Element simulations. For this work, the author received the Young Engineers Innovation Award for Structural Maintenance 2014 (Nachwuchs-Innovationspreis Bauwerkserhaltung) granted annually by the Bundesverband Feuchte & Altbausanierung e.V. in Germany.

Stephanie Franck (2014). Nachbildung von Schäden an Mauerwerksgewölbebrücken mittels nichtlinearer Finite-Elemente-Simulationen. BuFAS e.V., Altbausanierung 9, 25 Jahre Feuchte & Altbausanierung, 25. Hanseatische Sanierungstage, 30. Oktober – 1. November, 2014, Heringsdorf / Usedom, Fraunhofer IRB Verlag, Beuth Verlag, Berlin, 175-184.

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Real and simulated crack pattern in a masonry arch bridge

ATENA seminars in Prague

The new ATENA version 5.3 will be used throughout the seminars.



The seminar will give you deeper theoretical background into ATENA material models and solution techniques. It concentrates on advanced features available in ATENA Science, GiD-pre-post/processing, dynamic, eigenvalue, creep, thermal or fire analyses.

Both seminars will take place in Prague, Czech Republic.
First on February 10-12, 2016, in Czech language, second on June 15-17, 2016 in English language.

 

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Where You Can Meet Us

Future events:


November 8-12, 2015
ACI Fall 2015
Denver, USA
Event website

November 25-26, 2015
Concrete Days 2015
Litomyšl, Czech Republic
Event website

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Past event: Červenka Consulting in Hainburg


Beginning October 2015 our company participated actively at the 11th Central European Congress on Concrete Engineering "CCC", which has been organized under the motto  "Innovative Concrete Technologies in Practice" in Hainburg, Austria. In our exhibition stand Martin Berka presented our latest software product ATENA and SARA as well as our consulting services. Results from our research and information about our consulting project we presented in two papers and in a lecture on "Probabilistic safety assessment of long-span RC girders" given by Radomír Pukl. Poster about "Non-linear analysis of SFRC segmental tunnel lining" was prepared by Tereza Sajdlová in cooperation with colleagues from SUDOP Praha and Metroprojekt. Moreover, several successful applications of ATENA software to the nonlinear modeling of RC structures were presented by our customers such as Technical University of Budapest, TU Vienna, and  JKP Static Ltd. company from Hungary.

Recent Articles

ČERVENKA, J., PLACHÁ, M., PUKL, R.: Prestressing Optimization by Nonliner Analysis of Troja Bridge in Prague, Bridge design & engineering, August 2015

ČERVENKA CONSULTING: Nichtlineare Bemessung von Beton- und Faserbetonstrukturen, Beton- und Stahlbetonbau, 09/2015

KABELE, P., PUKL, R., SAJDLOVÁ T.: The Issue of Numerical Analysis of Fibre Reinforced Concrete Structures, in: Proceedings of the Fibre Concrete 2015, CTU in Prague

PUKL, R., SAJDLOVÁ T.: Probabilistic Safety Assessment of Long-span RC Girders, in: Proceedings of the 11th CCC Congress Hainburg 2015, Czech concrete society

BALÁŽ, D., MAREK, M., PUKL, R., SAJDLOVÁ T.: Non-linear Analysis of SFRC Segmental Tunnel Linning, in: Proceedings of the 11th CCC Congress Hainburg 2015, Czech concrete society

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