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Newsletter April 2017

Dear business partner,

we are happy to present you our Newsletter April 2017. It contains the information about the development in our continuous endeavor to bring the latest accomplishments in the numerical modeling of reinforced concrete to your desk. The new release of ATENA version 5.4 represents another step in our software development. The most important new features are described on our website along with a selected successful application example from our users. We would also like to invite you to our training seminar to Prague in June and to visit us during the coming presentations or exhibitions this year.

New Release of ATENA Software

ATENA version 5.4 brings many new and exciting features mainly to increase the support for modeling practical problems in bridge engineering or to improve the support for large scale models.

New finite elements:

ATENA now supports also classical 1D beam and 2D shell elements. 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:

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

- Evolution diagrams of reinforcement quantities such as stresses, strains, etc.
- Calculation and visualization of internal forces, 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

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. 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.

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Crack development in the analysis of FRC tunnel tubbing

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Failure of a model strengthened by FRP fabric

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.

Tutorial for ATENA Science GiD Construction Process
- Construction process involves changing of structural geometry or properties during the construction. ATENA simulation system allows changes both in geometry, loads, boundary conditions as well as material properties at any time during  the analysis.


The first tutorial covers the application area of bridge construction. ATENA, however, supports also the modelling of tunnel construction process. This tutorial is currently under preparation and will be released before the end of the year. Please follow the download section on our website to learn about the new tutorials as they will be released.

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Maintenance and support

We strongly support our users in their analytic work with ATENA. Support is mainly provided by email and phone calls. The solution to many questions can be found also in our FAQ & Online Forum. Please also contact us if you wish to extend/renew your maintenance. New versions of ATENA are released every year.

The recommended way to get the current ATENA version is to run the ATENA Update Check utility. If the license in your HASP key does not allow to run the current version, please follow the instructions from http://www.cervenka.cz/download/atena/manual-to-upgrade-your-hasp-for-atena-v5.

 

Success Stories

Analysis of the Shear Behavior of Prestressed Concrete Spliced Girders

Dhiaa Mustafa T. Al-Tarafany, Ph.D., The University of Texas at Austin, 2016

Implementation of the spliced girder technology in bridges has been growing in recent years. Increased girder lengths can now be realized by splicing shorter precast segments to produce a long span. The research conducted in this dissertation is focused on an evaluation of spliced girders using a three dimensional finite element analysis.

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The project consisted of a series of tests that were conducted in two phases. In Phase I, the effect of post-tensioning ducts on the shear behavior and strength of prestressed concrete girders was evaluated. In Phase II, the focus was on the behavior of cast-in-place splice regions between precast segments.
Since a limited number of full scale beams could be tested, a three-dimensional advanced finite element program is an effective alternative to expensive tests. The parameters considered were grout to girder concrete strength ratio, splice to girder concrete strength ratio, concrete shear key detailing, coupler diameter, duct to web width ratio, shear span to depth ratio, and concrete shrinkage losses. The findings are described in detail. Using the experimental and analytical results, it was found that the grout to concrete strength ratio for grouted ducts should not to be less than 0.3. The effect of increasing the duct diameter to web width ratio from 0.43 to 0.57 was minimal. Splice to girder concrete strength ratio should be greater than 0.6. The addition of a shear key had no effect on the shear capacity of the girder. The coupler diameter in the splice region had no effect on the behavior of the spliced girder for coupler diameter to web width ratio up to 0.55. Including concrete shrinkage in the analysis slightly improved the correlation with observed response.

Stability analyses of the partial face advance at the cavern from the access tunnel Wolf, BBT

J. Cervenka, Tereza Sajdlova, T. Cordes, K. Bergmeister

Cervenka Consulting s.r.o, Prague, Czech Republic
Brenner Base Tunnel BBT-SE Innsbruck, Austria

Nonlinear analysis of the Brenner Base Tunnel is presented. The nonlinear analysis is performed with the finite element simulation software ATENA, which enables advanced modeling of brittle materials such as concrete or rock. The rock is modeled using the Drucker-Prager material and concrete by the advanced fracture-plastic material. The interface between concrete and rock is modeled using interface elements with Mohr-Coulomb material.

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The analysis takes into account the construction process and the associated relaxation of the lining pressure. The calculated settlements show a very good agreement with the measured values.

The tunnel excavation and construction follows the new Austrian tunneling method, which allows for significant relaxation of rock mass stresses thus significantly relieving the pressure on the tunnel lining. The excavation process including the pressure relaxation is considered in the modeling approach and the measured convergences are compared with the numerical results and a very good agreement was observed.

See video here.

ATENA Advanced User Seminar 2017

Dear ATENA users,

we are happy to invite you to our ATENA Advanced User Seminar 2017!

The seminar will take place in Prague, the Czech Republic on June 14-16, 2017. The content of the seminar is rearranged such that it concentrates on fewer topics, but provide a 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 indepth explanation or background information.

Theme

The new ATENA version 5.4 will be used throughout the seminar. The version 5.4 brings several new and interesting features as described in more detail on our website such as: 

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  • new finite elements for 2D shells and 1D beams
  • diagrams for internal forces (MNQ) also for continuum elements
  • diagrams for 1D elements: reinforcement stresses, bond stresses or bond slip
  • modelling of pre-stressing losses
  • loads at arbitrary locations
  • user defined views
  • new tutorial problems and manuals for selected problem types:
    - fiber reinforced concrete: FRC, EEC, SHCC, HPFRC, UHPFRC
    - strengthening by carbon fiber rods, lamellas or sheets
    - construction process modelling

Registration

It is recommended to register on-line as soon as possible, the number of participants is limited. More information you can find on ATENA seminar website.

It would be our pleasure to welcome you in Prague at the end of spring this year!

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Where You Can Meet Us

April 27-28, 2017
Mosty 2017
Brno, Czech Republic
Event website

June 5-7, 2017
AMCM 2017
Gliwice, Poland
Event website

August 31-Sept 1, 2017
CCC 2017
Tokaj, Hungary
Event website

September 3-8, 2017
ICACMS – RILEM Week 2017
Chennai, INDIA
Event website

September 13-16, 2017
Fibre Conctrete 2017
Prague, Czech Republic
Event website

September 21-22, 2017
BESTInfra 2017
Prague, Czech Republic
Event website

September 21-23, 2017
39th IABSE Symposium
Vancouver, Canada
Event website

September 27-29, 2017
ConSC 2017
Stuttgart, Germany
Event website

October 15-19, 2017
ACI Fall 2017
Anaheim, CA, USA
Event website

Recent Articles

ČERVENKA, J., SAJDLOVÁ, T., CORDES, T., BERGMEISTER, K., 2017. Stability Analyses of the Partial Face Advance at the Cavern from the Access Tunnel Wolf, BBT. In: EURO:TUN 2017, Innsbruck University, Austria, 7 pages

ČERVENKA, V., ČERVENKA, J., SAJDLOVÁ, T., PUKL, R. 2016. Uncertainty Of Predicting Shear Strength. In: Czech Concrete Days 2016, 6 pages, Czech Concrete Society (ČBS ČSSI), ISBN 978-80-906097-6-1

MAREK, M., GRAMBLIČKA, M., BALÁŽ, D., PUKL, R., SAJDLOVÁ, T., STAŠ, M., SCHNEIDER, J. 2016. Steel Fiber Reinforced Concrete Precast Tunnel Segments: Design Using Nonlinear Analysis. In: Underground Construction Prague 2016 / EETC 2016, Session 5, Paper No. 15, 9 pages. ISBN: 978-80-906452-0-2

PUKL, R., NOVÁK, D., ČERVENKA, J. 2016. Fully Probabilistic Non-Linear Safety Assessment For Performance-Based Design Of Concrete Structures. In: fib Symposium 2016: Performance-based approaches for concrete structures, H. Beushausen (Editor), Cape Town, South Africa, November 2016. Paper No. 35a, 10 pages. fib, Lausanne, Switzerland, ISBN 978-2-88394-121-2

PUKL, R., PÁLEK, P., ČERVENKA, J. 2016. The possibility of using BIM for nonlinear life-cycle analysis of concrete structures. In: IALCCE 2016: Life-Cycle of Engineering Systems: Emphasis on Sustainable Civil Infrastructure, Bakker, Frangopol & van Breugel (Eds), Taylor & Francis Group, London, pp. 655-661, ISBN 978-1-138-02847-0

PUKL, R., SAJDLOVÁ, T., ČERVENKA, J., ČERVENKA, V. 2016. Performance of Fibre Reinforced Concrete Structures - Modelling of Damage and Reliability. In: CONSEC 2016, Lecco, Italy. Key Engineering Materials, Vol. 711, pp. 690-697, ISSN: 1662-9795, Trans Tech Publications, Switzerland. doi:10.4028/www.scientific.net/KEM.711.690

PUKL, R., SAJDLOVÁ, T., ŘOUTIL, L., NOVÁK, D., ŠEDA, P. 2016. Case study ‒ Nonlinear reliability analysis of a concrete bridge. IABMAS 2016, Foz do Iguacu, Brazil

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