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December 2011, Issue 6

Editorial..................................................................... 1

Two outstanding engineers: Marcel Tschumi and Joël Kruppa ...................................................................... 3

“Life is So Concrete” – 20th BIBM International Congress and exhibition........................................... 4

In Memoriam – Andrew Beeby................................. 5

Eurocodes workshop in Georgia .............................. 6

News from JRC ........................................................ 7

Moscow State University of Civil Engineering honours Eurocode authors ..................................................... 8

From construction products to building works: the European input ......................................................... 9

CEOS.fr - Behaviour and assessment of special construction works: concrete cracking & shrinkage13

Second International Workshop “Design of concrete structures and bridges using Eurocodes”............... 16

Editorial

The last TC250 Newsletter was published in May 2011 and many events have taken place since then. One of the major events was the finalization of the response to the “Programming Mandate M/466” concerning the future work for the Eurocodes.

The mandate M/466 in the field of Structural Eurocodes was formally sent to CEN on the 25th of May 2010. After long discussions within CEN/TC250 (21st ENC Group meeting in Brussels on the 13th of April 2011, 39th meeting of CEN/TC250 in Ispra on the 26th and 27th of May 2011), CEN replied to the mandate with proposals, work plans and a time strategy on the 30th of June 2011.

On the 25th of October 2011, a meeting was organized by the Commission (Manfred Fuchs) with the participation of Barry Haseltine and Jean-Armand Calgaro.

A report of this meeting is given hereafter.

1. The meeting was held to discuss the preliminary views of the Commission on the reply of CEN to the mandate M466, document

TC/250 N914. The reply has been placed on CIRCA for information, but not (yet) for comment.

2. Manfred Fuchs explained that he was able to spend one third of his time on Eurocodes. He was grateful for the reply and had read it all through; he was concerned by the extent of the programme and doubted the Commission’s ability to fund it all, and also CEN/TC250’s ability to manage such a large programme. He confirmed that he had decided not to involve the ENC group in the “simplification” process, so there would not be an ENC ad hoc group for that purpose.

The JRC shall provide a platform for all activities in this field to allow CEN and all other stakeholders to get an overview and learn form examples.

3. Jean-Armand Calgaro tabled a plan showing the possibilities for new and old groups to work together on new versions of Eurocodes. He foresaw a programme of several years (as with the conversion of ENVs to ENs), with necessary prioritisation of work items into those years.

4. Manfred Fuchs foresaw a maximum of three packages to cover all of the work. No indication of the funding will emerge until the detailed work programmes are developed and have been submitted through CEN to the Commission. The only indication that he could give was that the total budget for standardisation work across all fields is about 4.000.000 € per year. Management of any programme is a prime user of funding (in the conversion programme, about 50% of the money went to NSBs for management). Funding for a programme spread out over a number of years would depend on the other demands being made at the relevant times.

5. A specific work item is needed for all parts, either revisions of existing or new parts. The level of detail in the reply is inadequate for future use, and a new schedule must be

The newsletter of CEN/TC250 is available at http://eurocodes.jrc.ec.europa.eu

Editors

Jean-Armand Calgaro, Chairman of CEN/TC250 Georgios Tsionis, University of Patras

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prepared. A spreadsheet has been prepared by initiated by Barry Haseltine, which will need to be completed by the chairmen of subcommittees and working groups.

6. Manfred Fuchs will send the reply to members of the ENC group for comments, giving perhaps four weeks to do so. At the same time, he will produce a draft specific mandate for discussion. After receipt of replies, a meeting of the ENC group will probably be called, possibly in April.

7. Jean-Armand Calgaro explained how absence of a direct interest from industry can make financial support for drafting imperative. For example, there are no specific industries behind EN 1990 and EN 1991, the concrete industry for EN 1992.

8. After some discussion, it was thought that package 1 could consist of EN 1990, EN 1991, EN 1997, EN 1998, the “head” parts of Working Group 2 (assessment of existing structures) and Working Group 6 (robustness) and any necessary involvement of the Horizontal Group Bridges and Horizontal Group Fire.

It does not follow that all of the individual items listed in the reply will be treated, but this will depend on detailed discussions on the work items after they will have been prepared.

Package 2 could consist of the items that lead to improvements in existing codes and their use, including material-dependent additions related to robustness (Working Group 6) and structural glass (Working Group 3).

Package 3, if it is required that there be three packages, might cover fibre-reinforced polymers (FRP - Working Group 4), membrane structures (Working Group 5), and the material-dependent aspects of Working Group 2.

Manfred Fuchs was concerned that FRP and membrane structures were more “niche” topics, with not enough empirical research and “ground work” in the field of harmonisation, which would hardly justify funding by the Commission at that stage. This does not exclude financing from industry, though.

If it turns out that only two packages are required, then the work listed in package three will need to be re-allocated.

9. Manfred Fuchs plans to attend the CEN/TC250 Coordination Group meeting in London to get comments on the draft specific mandate. The draft mandate will then be completed by the end of March, in time for an ENC meeting in April. CEN/TC250 should see the draft specific mandate and the ENC comments in May. The mandate has to be sent to the 98/34 committee, whose timetable is difficult to estimate.

Detailed planning of work items would have to be done with CEN and could start in May. Funding

would be dealt with as a parallel exercise to the preparation of work items. The Commission would be involved in the development of financial aspects, so that availability of funds could be fed into the detailed programming. This would likely mean that further prioritisation would have to be assessed if there were not to be sufficient funds for all desired work items. Manfred Fuchs together with two other members of the Commission staff will be involved.

Final work items should be ready for the CEN/TC250 meeting in November 2012, so that the bureaucracy could be completed for approval in early 2013 and the work can start in mid-2013, hopefully.

10. How coordination is handled is not clear and should be discussed with CEN. This affects chairmen of subcommittees, working groups and horizontal groups.

11. Manfred Fuchs was disappointed to hear that improvements in user-friendliness (“simplification”) could not be expected as a separate exercise from the work foreseen in the work items that are proposed in the reply. He requested that CEN/TC250 should try to prepare documents (could be published as Technical Reports) that would assist users with the existing parts, possibly using “road maps” or other ways, such as the Danish partial publications. Manfred Fuchs would prefer such help to be given through CEN/TC250 rather than to appear piecemeal from countries. He was also concerned that after criticism about the complexity of the Eurocodes, not providing any guidance to simplify the work of end-users before about 2018 might seriously harm the acceptance of Eurocodes and the standardisation work in CEN/TC250.This subject needs to be discussed in Prague.

As a conclusion, 2012 should be a positive year to find a support from the Commission.

Visit of ELSA Laboratory in May 2011

The CEN/TC250 Meeting in Ispra has been very positive to formulate the response to the Mandate M466.

Jean-Armand Calgaro Chairman of CEN/TC250

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Two outstanding engineers: Marcel Tschumi and Joël Kruppa

Marcel Tschumi

Marcel Tschumi, born on the 26th of May 1938 in Berne, Switzerland, obtained his civil engineering diploma at the Swiss Federal Institute of Technology (ETH) in Zurich in 1962. Since then he has been involved in the design of structures and bridges.

Dr Marcel Tschumi

He was awarded the title Dr Honoris Causa from the Technical University of Bucharest in 1995. Before his retirement on the 31st of August 2002, he was Head of Civil Engineering at the Fixed Asset Management Department of the Swiss Federal Railways, Headquartered in Berne, where he was responsible for bridges, tunnels and retaining walls.

He was also Chairman of the Expert Group “Civil Engineering” of the International Union of Railways (UIC) from 1988 to 2001.

From 1988 Marcel Tschumi led the team that prepared the draft of EN 1991-2 “Actions on structures - Traffic loads on bridges” as well as the parts of Annex A2 to EN 1990 which relate to railways. He also worked on the drafting of the final versions of these two documents.

The Charles Bridge in Prague, from Marcel Tschumi’s stamp collection

He attended the last meeting of the Horizontal Group “Bridges” in Köln (1-2 December 2011) and then he retired definitively.

He is a nice man, a specialist of railway bridges and he worked very hard to finalise his Part of EN 1990 and EN 1991. But he has other activities: his passion is not only for bridges, but also for stamps with bridges like the old stamps showing the Charles Bridge over the Moldau in Prague.

Thank you, Marcel.

Joël Kruppa

Joël Kruppa is Director of Research & Valorisation of CTICM in France. He is doctor in fire resistance of steel structures.

Since 1993 he has been convenor of the Horizontal Group “Fire” (HGF) of CEN/TC250, covering structural fire design of concrete, steel, composite, masonry and aluminium alloy structures.

Prof. Joël Kruppa, chairman of HGF

From 1999 to 2011 Joël has been chairman of ISO/TC92/SC4 dealing with fire safety engineering and chairman of the French mirror group.

He is professor of fire resistance engineering at the Ecole Nationale des Ponts et Chaussées. He was co-director of a French research project (2005-2011) on the implementation of fire safety engineering in France.

He expressed his intention to stop his activity as chairman of HGF and the CEN/TC250 meeting in Prague was his last plenary meeting.

Thank you Joël for all what you have done.

Jean-Armand Calgaro Chairman of CEN/TC250

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“Life is So Concrete” – 20th BIBM International Congress and exhibition

The 20th BIBM international congress and exhibition was held in Cannes (France) on 16-17 June 2011. For two days the town of Cannes was the European capital of the precast concrete industry as all those involved in the European concrete industry gathered for the BIBM Congress under the banner “Life is so concrete”.

Manufacturers, suppliers, specifiers, buyers, users and all interested parties flocked to the prestigious Carlton Hotel on June 16 and 17, 2011. More than 400 participants – not just from every corner of Europe but also from Brazil, South Korea and Saudi Arabia – took part in debates and round tables.

The conference room at the Carlton Hotel

This three-yearly congress run by BIBM since the 1950s takes place in a different European country every time: the 2011 congress was organized in France by the Fédération de l’Industrie du Béton (FIB), with the scientific support of the Study and Research Centre for the French Precast Concrete Industry (Centre d’Études et de Recherches de l’Industrie du Béton – CERIB).

As Pierre Brousse stressed in his opening address, “BIBM, the European federation for the precast concrete industry, fosters the international dimension of its national members and represents the industry’s ambition to cooperate and to speak as one voice in today’s globalized world”.

Bearing this in mind, the event hinged upon meetings and debates aimed at presenting the latest developments and the future prospects of an industry that is firmly in step with society, offering precast concrete products that are part of everyday life. The challenges facing tomorrow’s world – such as achieving an environmental balance and the social issues involved – were the focal point of discussions led by prominent European figures.

Around thirty specialist speakers – architects, town planners, sociologists, scientists, academics, engineers, heads of European companies – presented their viewpoints and shared their experience.

Under the heading “Life is so concrete”, the precast concrete industry addressed at its 20th international congress several topics of the upcoming policies and legislation at the European level, as well as market trends. The congress was organized with round tables

and workshops: o Round Table 1: Sustainable construction of new

towns

o Round Table 2: Society is evolving, concrete industry and civil engineering companies are evolving

o Round Table 3: Construction systems and seismic risk

o Round Table 4: Concrete - it's hard to build better

o Workshop 1: Concrete solutions for architects and town planning specialists

o Workshop 2: Risks due to fire in buildings o Workshop 3: Energy performance of concrete

buildings

o Workshop 4: Innovation in concrete production industry

The major topics developed during the congress were mainly devoted to the sustainable construction, the sustainable development of future cities, the evolution of concrete industry and building companies to better take into account the new societal needs, the answers of concrete industry for the construction of buildings in seismic zones and the contribution of concrete industry to the improvement of the environment of citizens.

The topic of the opening round table was “Building the sustainable cities of tomorrow”. Speakers insisted on the need to clearly position Man and Nature at the core of urban projects by integrating the benefits of new technologies to offer residents a better living environment.

The second round table addressed the changes society has undergone and their effects on construction and development requirements. In a situation where today’s economic model is evolving towards an as-yet indistinctly demarcated economic-environmental paradigm, the precast concrete sector and the companies working in it enjoy advantages that combine the reduced environmental impacts of their solutions with their organization’s ability to adapt.

In parallel with economic evolution, sociological and societal phenomena (population growth and ageing, mobility, etc.) are accentuating requirements, particularly in terms of housing. The precast concrete industry can meet these challenges with innovative, high-performance, customized solutions.

The third round table presented construction systems and seismic risk. Events in Aquila, Fukushima and Murcia have reminded us that it is vital to take seismic risk into account in the design of construction systems. Eurocode 8 includes calculation methods for designing buildings in earthquake-prone regions. The participants to this third round table were Prof. J.-A. Calgaro (CEN/TC250 Chairman), Prof. M. Menegotto (Chairman of the fib prefabrication commission), Prof. G. Toniolo (Chairman of SAFECAST project, which focuses on improving

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The panel for the third round table : Prof. Toniolo, Prof. Calgaro, Mr. Grafeille, Prof. Menegotto, Mr. Juraszek

concrete construction systems to cater for seismic risks), Eng. N. Juraszek (CERIB) and Captain D. Graffeille of the Brignolles civil defence unit. In his presentation, Captain Graffeille, who had just returned from Japan, stressed how well structures built in accordance with seismic-design codes have stood up to earthquakes, and he asked for greater co-operation between manufacturers and urban-rescue specialists to contribute to a better robustness of buildings in seismic zones. One important issue of the discussion was the possibility to inform safety teams on the possibility to get into a damaged construction to give first aid to people injured during an earthquake.

The last round table discussed the precast concrete industry’s very real contribution to the improvement of living conditions, giving users of its solutions an opportunity to speak. Whether in the fields of architecture and aesthetics or in its environmental and societal commitments, experience proves that the precast concrete industry has its finger on the pulse of life.

The various workshops gave an overview of the performance of precast concrete products throughout Europe.

The first workshop presented concrete solutions for architects and urban planners. Complementarity between the expertise of architects and that of manufacturers is essential for the development of construction solutions perfectly adapted to the expectations of builders, including in respect of innovative applications such as self-cleaning materials and elimination of pollution. Cement and admixture manufacturers contribute to the success of projects by optimizing the solutions proposed and by improving the conditions of their implementation.

The second workshop dealt with the prevention of fire risks. The most eminent European specialists and academics have redefined the key role of fire safety engineering (FSE), particularly with respect to the undertakings of rival techniques. They have exposed the main avenues on which to engage work to define a FSE strategy for the European precast concrete industry.

The third workshop surveyed the main European energy-efficiency benchmarks for buildings (PassivHouse, Bâtiment Basse Consommation) and highlighted the solutions already provided by the industry.

The last workshop examined the innovations introduced into concrete manufacturing processes through the new technologies developed in Europe by admixture producers and precast concrete manufacturers in order to improve the industrial quality and performance of concrete products.

Marc Lebrun Chairman of CEN/TC229, Chief Executive Officer of CERIB

In Memoriam – Andrew Beeby

It can be stated without exaggeration that Andrew Beeby has had a significant influence in the way reinforced concrete design is carried out in the UK and to an extent in Europe and other countries. This stems from his original research leading to practical application, his influential publications (over 120) and his active participation in code drafting in the UK and Europe.

After graduating in 1960 from Northampton Engineering College (then a college of London University now City University), Andrew Walter Beeby joined John Laing & Sons and worked on site and in the design office for four years on motorways and multi-storey structures.

In 1964 he took up a position as Research Engineer with the Cement and Concrete Association (C&CA). His tasks included an extensive research programme on the prediction and control of cracking in reinforced and pre-stressed concrete, monitoring of structures in service and development of design aids. He was also concerned with the drafting of the first British Code of Practice (CP 110) using limit state principles. In 1971, Andrew was awarded a PhD by London University for his thesis “The prediction of cracking in reinforced concrete members”.

Between 1978 and 1988 he took up different positions within C&CA culminating in his appointment as the Director of Design and Construction. In this period his research covered a wide range of topics, such as impact resistance of concrete beams, cracking and corrosion, alkali-silica reaction, shear and bond.

In 1991, Andrew Beeby took up the position of Professor of Structural Design at the University of Leeds. Alongside his teaching, he continued his research and code drafting activities. The research included the influence of ductility on the performance of reinforced concrete members, behaviour of slab systems during construction using the full scale experimental structure at Cardington, the long term inter action of steel and concrete in tension (tension stiffening), membrane effects in frames and safety of structures.

Andrew Beeby was involved with CEB and fib since the early 1970s, when he participated in the work of CEB commissions on cracking, calculation and

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limitation of deflections, and bending and compression. He participated actively in all of these commissions, leading up to the publication of the 1978 Model Code. He later became a member of Commission 5: Serviceability, and of General Task Group 20: Durability and Service Life of Concrete Structures, contributed to the CEB Design Guide on Durable Concrete Structures, and was chairman of CEB Commission 2: Material and Behaviour Modelling. He was a member of the CEB Advisory Committee and later the fib Steering Committee, head of the British national group in CEB for many years, and was the first Editor-in-Chief of the Structural Concrete Journal, a position he held until 2001.

He was an active member of fib Special Activity Group 2, Dissemination of knowledge, contributing to both the first and second editions of the fib Structural Concrete textbook (Bulletin 2 in 1999 and Bulletin 52 in 2010). In 2004 he was awarded Honorary Life Membership in fib, in recognition of his many achievements and contributions.

Andrew’s technical contribution to code committees has been prodigious. Some areas of both British Standards and Eurocodes derive directly from his research in the area of serviceability. His work on cracking in the 1960’s has stood the test of time and remains the basis for the design of crack control in concrete structures. His studies in the 70’s on corrosion and cracking still form the basis of views on the subject more or less world-wide.

Andrew commanded wide respect throughout the industry. His standing and reputation are indeed high throughout the world. He was awarded the Fellowship of the American Concrete Institute in 1991, and in 2000 the Institution of Structural Engineers honored him with their prestigious Lewis Kent Award. He was elected a Fellow of the Royal Academy of Engineering in 2003. This recognition particularly pleased him. In his own words he was “thoroughly chuffed”!

He was handicapped by an illness soon after his retirement from the University in 2004. This was a cruel blow, but for which he would have contributed even more in his field.

Andrew was a mild mannered and courteous, private man. For all his achievements, he was very modest.

He is survived by his wife Greta, two sons and a daughter.

Concerning the Eurocodes, Andrew Beeby carried out much of the work on the ENV Eurocode 2 drafted by the BCA in the UK. He chaired the working group that produced EN1992-3 and contributed significantly to the development of the cracking rules in EN1991-1-1, an area where there was much debate.

Tony Jones Associate Director, Advanced technology + Research, ARUP

Eurocodes workshop in Georgia

Following a request from the Ministry of Economy and Sustainable Development of Georgia, a workshop on “Implementation of Eurocodes in Georgia” was organized by TAIEX with the technical support of the JRC and CEN/TC250. The workshop was held in Tbilisi, Georgia on 26-27 September 2011 with the aim of providing assistance for a successful implementation of the Eurocodes in Georgia.

Eurocodes workshop in Tbilisi, Georgia

The workshop was very well attended with approximately 140 invited participants, representing Georgian national authorities, building and construction associations, construction industry associations, professionals and practitioners, and academics. It was the first event organized in Georgia presenting the Eurocodes and the participants showed keen interest during the event to learn more about the Eurocodes.

The experts presented information that gave a solid global understanding on the scope, structure and general concepts of the Eurocodes.

The experts underlined the benefits from using the Eurocodes for the construction sector, the industry and practitioners.

The experts gave advice on the development of the National Annexes and setting the National Determined Parameters.

Many structures and bridges designed according to the Eurocodes were presented as successful examples.

The support provided by the Commission in the Implementation of the Eurocodes in the Member States was presented – the participants were very interested in the training workshops organised by the JRC in collaboration with CEN/TC250.

The experts noted that follow-up events are necessary so as not to lose the momentum from this first event, for example: i) a training workshop with technical content, targeted to professionals and academics, (ii) experts’ visit to assist Georgian authorities in implementation/adaption of Eurocodes.

A. Athanasopoulou Joint Research Centre, European Commission

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News from JRC

The European Commission’s Joint Research Centre (JRC) continues to provide support to the implementation, harmonisation and further development of the Eurocodes by developing informatics tools that facilitate the practical implementation of Eurocodes, fostering training and promotion of the Eurocodes within and outside Europe, producing policy support documents and technical reports and facilitating further harmonisation works.

Informatics tools

The European Commission website on Eurocodes (http://eurocodes.jrc.ec.europa.eu) is continuously being updated with training and awareness events, publications and other material on the Eurocodes. Furthermore, JRC is collecting guidance material (books, manuals, informative leaflets, etc.) on the Eurocodes and also information about state-of-the-art structures designed following the Eurocodes for publication in the website. Thus, the contribution of information on events and publications related to the Eurocodes as well as examples of structures is highly encouraged and appreciated.

The Centralised Eurocodes Helpdesk, an IT platform developed by JRC in order to assist the communication between the National Standardization Bodies (NSBs) and CEN/TC250, is currently being tested by CEN/TC250 members and will soon be in operation. The Helpdesk will provide the informatics infrastructure by which the NSBs will submit/direct questions received from Eurocodes users on national level to CEN/TC250.

Nationally Determined Parameters (NDPs) Database

JRC is continuously monitoring the status of uploading of the Nationally Determined Parameters (NDPs) to the database aiming to carry out analysis for further harmonisation and evolution of the Eurocodes. With recent contributions of Spain and Germany within the second semester of 2011, 25 EU member states, two EFTA countries and one EU candidate country are registered to the database, while 22 countries are currently uploading their NDPs to the database. Approximately 26% of the total expected NDPs have been uploaded and some countries have already completed or almost completed their uploading (i.e. Czech Republic - 100%, Slovenia - 86%, Norway - 86%, Romania - 75%).

At this stage, the data available cannot be treated yet as a representative sample of all the expected data and thus only preliminary conclusions can be derived regarding further harmonisation works for the Eurocodes. A preliminary analysis of the available data shows that the mean percentage of acceptance of the NDPs’ recommended value is 75%.The highest percentages of acceptance of the recommended values are for EN 1992 (~80%), EN 1993 (~87%) and EN 1994 (~89%). Within

0%

5%

10%

15%

20%

25%

30%

35%

EN 1990

EN 1991

EN 1992

EN 1993

EN 1994

EN 1995

EN 1996

EN 1997

EN 1998

EN 1999

Perc

en

tag

e o

f u

plo

ad

ed

ND

Ps

Nov-08…Nov-10

May-11

Jul-11

Sep-11

Oct-11

Percentage of uploaded NDPs for each Eurocode in the period November 2008 to October 2011

the second semester of 2011, not only the number of uploaded NDPs with recommended values increased, but also the percentages of acceptance have ascended. The rate of high acceptance may be interpreted as an indication of the unification of European construction practices, especially for reinforced concrete, steel and composite structures.

As a special case study, JRC performed a statistical analysis for a selected set of countries and a group of NDPs for EN 1992. The results of the case study were presented in the International Conference “Design of concrete structures and bridges using Eurocodes” held in Bratislava on 12-13 September 2011 (A. V. Pinto, A. Athanasopoulou, M. Poljansek and B. Acun, Implementation, Harmonization and Further Development of the Eurocodes – A case study on Eurocode 2).

Training and promotion of the Eurocodes

In order to facilitate the implementation and use of the Eurocodes, JRC is preparing technical reports containing the practical examples presented in past Eurocodes workshops with worked examples. These workshops have been organized by the JRC in collaboration with CEN/TC250 sub-committees, DG ENTR and national authorities/contact points. Two reports are currently edited by JRC and will soon be published and available to download from the Eurocodes website, namely:

o Bridge Design to Eurocodes – Worked examples (Y. Bouassida, E. Bouchon, P. Crespo, P. Croce, L. Davaine, S. Denton, M. Feldmann, R. Frank, G. Hanswille, W. Hensen,B. Kolias, N. Malakatas, G. Mancini, M. Ortega, G. Sedlacek, G. Tsionis)

o Eurocode 8: Seismic Design of Buildings – Worked examples (P. Bisch, E. Carvalho, H. Degee, P. Fajfar, M. Fardis, P. Franchin, M. Kreslin, A. Pecker, P. Pinto, A. Plumier, H. Somja)

Further, the series of training and dissemination events organized by JRC continued with a workshop dedicated to the design of concrete buildings following Eurocode 2. The workshop “Eurocode 2: Design of Concrete Buildings” was held in Brussels (20-21 October 2011). The workshop, targeted to trainers at national level, designers and Eurocode users had emphasis on worked

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120 participants from Europe and abroad attended the JRC workshop on the design of buildings with Eurocode 2

examples. The step-by-step design of a reinforced concrete cast on site building following Eurocode 2 was presented with each session focusing on a different part in the design process, namely: conceptual design, structural analysis, limit states design and verification, detailing of reinforcement and members, foundation and fire design. All the presentations from the workshop are published in the Eurocodes website.

Approximately 120 national delegates were registered to the Eurocode 2 workshop and 85 delegates attended the lectures each day of the workshop. The participants were delegates from the EU member states, EU candidate countries and EFTA member states. Participants also came from countries outside Europe (e.g. Israel, Malaysia, Morocco) showing keen interest in the European standards for construction. The participants had the opportunity to contact colleagues from other countries and exchange views and experiences on the implementation of Eurocodes (and in particular Eurocode 2) for the design of concrete buildings in their countries.The majority of the participants considered that the workshop was useful for subsequent training and promotion at national level and gave a very positive evaluation of the organization, the technical aspects and the overall impact of the workshop.

Mr. Tapani Mikkeli, Deputy Head of Unit from DG ENTR (Construction, pressure equipment and metrology Unit) gave a welcome speech and addressed the importance of Eurocodes and training workshops for the construction industry and policy making. In particular, Mr. Mikkeli referred to the importance of the JRC activities in support to the implementation, promotion and further development of the Eurocodes, underlying DG ENTR plans to continue the collaboration with JRC-ELSA Unit.

Evolution of Eurocodes to additional fields of design

JRC is promoting activities aiming to expand the concept of Eurocodes to additional fields of design and to incorporate aspects related to sustainability, energy efficiency and other emerging issues in the

design standards for construction. These activities are in close collaboration with CEN/TC250, CEN BT/WG 206 and other CEN technical committees with relevant scope of activities.

In this line, JRC participated and made a presentation at the CEN Construction Sector Conference “Interoperability and sustainability for construction” held in Brussels on 9-10 June 2011. The presentation focused on the objective to achieve a full set of compatible and interoperable standards for the design and assessment of buildings and other civil engineering works addressing all Basic Work Requirements (BWR) of the Construction Products Regulation (CPR). It was proposed that a “Head-Standard” (like EN 1990 – Basis of Design) should be developed for each BWR stating general principles in accordance with the CPR, leading to an integrated performance quantification and allowing also to set minimum performance requirements.

For further information visit the JRC website on Eurocodes http://eurocodes.jrc.ec.europa.eu or contact us at eurocodes@jrc.ec.europa.eu.

A. Pinto, M. Poljansek, A. Athanasopoulou, B. Acun Joint Research Centre, European Commission

Moscow State University of Civil Engineering honours Eurocode authors

On the evening of Monday, November 14 a ceremony was organised in Prague by a delegation coming from the Moscow State University of Civil Engineering (MGSU). The delegation was composed of M. Leybman, vice-rector, Prof. O. Egorychev, first vice-chancellor, Prof. I. Kirillov and Dr. O. Igorevna. During the ceremony, Prof. H. Gulvanessian, Prof. M. Holicky and Prof. J.-A. Calgaro received the title “Doctor Honoris Causa” of the University, the highest award of MGSU, for their multiple scientific services in the field of civil and structural engineering, particularly their work on development of the Eurocodes.

Prof. M. Holicky, Prof. J.-A. Calgaro and Prof. H. Gulvanessian during the award ceremony

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From construction products to building works: the European input

Introduction

The European Union is born from a step-by-step process designed by Jean Monnet and initiated by the famous declaration of Robert Schuman speaking on behalf of the French Government on 9 May 1950: “Europe will not be made all at once, or according to a single plan. It will be built through concrete achievements which first create a de facto solidarity. […] The pooling of coal and steel production should immediately provide for the setting up of common foundations for economic development as a first step in the federation of Europe, and will change the destinies of those regions which have long been devoted to the manufacture of munitions of war, of which they have been the most constant victims.”

France and Germany, together with Italy, Belgium, the Netherlands and Luxembourg, started in 1951 by creating the European Coal and Steel Community, and later on the European Economic Community which is, by far, the most important achievement. Its purpose, defined by the Treaty of Rome of 1957, was to establish a customs union, based on “four freedoms”: freedom of movement of goods, services, capital and people.

The economic growth over the years resulting from its implementation became so attractive that the European Communities enlarged progressively to many new Member States. But the opening of national borders was not enough to get a “common market” of free trade. On the contrary, a proliferation of national technical standards increased the partitioning of markets, so that, in 1986, the 12 Member States signed the “Single Act” in order to adopt the measures needed to eliminate all barriers to trade and to create effectively a single unified market.

A “New Approach” to technical harmonization and standards was adopted in 1989, providing a framework to harmonize national regulations for industrial products, and to develop flexible and technology-neutral legislation, by moving from detailed descriptive specifications for individual products, to defining the performance-based “essential requirements” for types of products, thus promoting innovation and competitiveness. This “New Approach” has been implemented for the construction sector in 1989 by the European Directive 89/106/EEC, called the “Construction Products Directive” (CPD).

Actually, the European legislation includes:

o European regulations, which are entirely binding and directly applicable;

o European directives, which are binding on Member States as to the result to be achieved, but leave to the respective national authorities to decide how the objectives set out in the directive are to be incorporated into their domestic legal system before a certain date, and

o European decisions applying the European legislation, which are binding only on those to whom they are addressed.

It is to be noted that a new “Construction Products Regulation” (CPR) has been voted by the EU Parliament in 2011, in order to revise and replace the CPD, and to upgrade its legal force.

Construction Products

For the purpose of the CPD, construction product means “any product which is produced for incorporation in a permanent manner in construction works, including both buildings and civil engineering works”. Shortly, it is what enters into the work site.

The basic principle of the CPD was established in 1979 by a judgment of the European Court of Justice (the so-called “Cassis de Dijon” judgment): a product sold lawfully in one Member State may not be prohibited in another Member State.

This principle of “mutual recognition” effectively reverses the burden of proof, by requiring a Member State, which does not want to accept such a product on its market, to demonstrate why compliance with the requirements of another Member State would not adequately protect its citizens.

Furthermore, the Court ruled that if there were European regulations, directives or decisions prescribing technical requirements for certain products, these exceed the national rules, and because the national rules give rise to trade restrictions, they would no longer be lawful when European technical requirements exist.

The CPD was drafted to prescribe such technical requirements for construction products, so that a product responding to its prescriptions cannot anymore be refused:

o Mandatory essential requirements are defined to ensure a high level of protection regarding health and safety. They must be worded in terms that can be uniformly enforced by Member States, and they must enable conformity assessment bodies to evaluate conformity of products and standardization bodies to develop standards to ensure, partly or completely, the fulfilment of those essential requirements.

o Manufacturers are free to choose any appropriate technical solution that meets the essential requirements.

o Products that comply with harmonized standards, references to which have been published in the Official Journal of the European Union, are presumed to meet the corresponding essential requirements.

Shortened version of a contribution given to the International Conference “Sustainable construction”, dedicated to the 90th anniversary of the Faculty of Industrial and Civil Engineering of the Moscow State University, 19-21 April 2011

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o Appropriate conformity assessment procedures are defined, taking into account, among other things, the type of risk related to the products. Where appropriate, these procedures require the intervention of third party conformity assessment bodies, known as notified bodies.

o For any product that is not covered or not fully covered by a harmonized standard, the manufacturer may request alternatively for a European Technical Assessment, and a European Assessment Document shall be drawn up and adopted by the organization of Technical Assessment Bodies.

o The CE Marking symbolizes the fact that the manufacturer has verified that the product conforms to all the harmonization provisions that apply to it and that the product has been the subject of the applicable conformity assessment procedures. In a “declaration of conformity”, the manufacturer presents the required information on the product and its characteristics, in the language of the Member State in which the product is to be used. Note that this “declaration of conformity”, required from the manufacturer by the CPD, will be replaced according to the new CPR by a “declaration of performance of the essential characteristics of the construction product”.

o Member States shall take all appropriate enforcement measures, including market surveillance, to ensure that non-conforming products are withdrawn from the market.

Performance of construction works and products

When we speak of performance, we mean the properties of a construction work that have to do with the behaviour demanded of it during use so that it correctly fulfils its functions. These properties are determined using unified sets of scientific methods (testing, measurement, calculation and observation) regardless of the materials

and processes used.

When specifying the performances of a building, rather than describing construction materials and processes in the specifications, we replace an “obligation of means” by an “obligation of results”. Various constructive solutions may thus be compared on an equal footing, while freedom as large as possible is left to the designer in order to encourage innovation.

A major step in the implementation of the performance concept in buildings has been accomplished at the joint RILEM-ASTM-CIB Symposium organized in 1972 by the US National Bureau of Standards, where many pioneering researchers and developers such as G. Atkinson (UK), O. Birkeland (Norway), G. Blachère (France), J. Eberhard (USA) and I. Karlen (Sweden) gathered and shared their experiences.

Short afterwards, the author began his engineer’s career within SECO on an ambitious Belgian inter-industrial/construction research program in this field, partly financed by the Belgian State. Under R. d’Havé, former Director of SECO, he drafted the “Performance Guide for Buildings” (R. d’Havé & P. Spehl, Guide des Performances du Bâtiment, Syndicat d’Etudes IC-IB, Brussels, 1980, 9 volumes), which presents the performance specifications, testing and calculation methods already available or developed at the time, and the international standard ISO 6241 “Performance standards in building – Principles for their preparation and factors to be considered”, in 1982, as technical secretary of a working group within the ISO/TC59 “Building construction” chaired by G. Blachère.

Both documents did inspire R. Mourareau of the European Commission, who drafted the CPD which states that the “harmonized standards” should be "expressed as far as possible in terms of product performance", and which has been since 1989 the basis of the whole European Commission policy to unify the market in the construction sector.

Annex I of the CPD defines the six essential requirements regarding health and safety, which are

ISO 6241 : 1984

Table 1: User requirements

CPD : 1989

Annex I: Essential requirements

CPR : 2011

Annex I: Basic requirements for construction works

1. Stability requirements

2. Fire safety requirements

3. Safety in use requirements

4. Tightness requirements

5. Hygrothermal requirements

6. Air purity requirements

7. Acoustical requirements

8. Visual requirements

9. Tactile requirements

10. Dynamic requirements

11. Hygiene requirements

12. Requirements for the suitability

of spaces for specific uses

13. Durability requirements

14. Economic requirements

1. Mechanical resistance and stability

2. Safety in case of fire

3. Hygiene, health and the environment

4. Safety in use

5. Protection against noise

6. Energy economy and heat retention

1. Mechanical resistance and stability

2. Safety in case of fire

3. Hygiene, health and the environment

4. Safety and accessibility in use

5. Protection against noise

6. Energy economy and heat retention

7. Sustainable use of natural resources

The essential requirements in ISO 6241 (1984), the Construction Products Directive (1989) and the Construction Products Regulation (2011)

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applicable to construction works in order to be fit for their intended use. This list may be compared to the standard list of user requirements from ISO 6241, where other aspects than health and safety are covered, and to Annex I of the new CPR, where a seventh requirement “Sustainable use of natural resources” has been added.

In addition to the CPD, for each essential requirement, an “interpretative document” defines qualitatively the performance characteristics to be required from the construction products in order that the construction works made of them will respond to the essential requirement concerned. These performance characteristics which are needed for the end use of products are then defined quantitatively in harmonized product standards referring to performance testing standards, calculation standards and classification standards.

It is to be noted that the jurisdiction of the European Union covers construction products, according to the CPD, but not construction works which remain in the jurisdiction of the Member States and their regulatory authorities.

National and European jurisdictions according to the CPD

CEN Standards

The European Committee for Standardization (CEN) gathers the national standardization organizations from the 27 EU Member States, one candidate to EU (Croatia) and the 3 members of the European Free Trade Association: Iceland, Norway and Switzerland. The standardization organizations of 20 other States are affiliated or partners and may take part to the CEN technical committee meetings, but without voting.

Although a weighted vote is used to approve standards, the aim of the works within working groups and project teams preparing them is to reach a “consensus”, which is defined by ISO as “a general agreement, characterized by the absence of sustained opposition to substantial issues by any important part of the concerned interests and by a process that involves seeking to take into account the views of all parties concerned and to reconcile any conflicting arguments (note: consensus does not necessarily imply unanimity)”. The good practice of this principle proves to be the best way to obtain standards widely accepted.

CEN has been mandated under the CPD by the European Commission to draft about 600 harmonized product standards (hEN) and about 1500 standards on

performance test methods. This vast standardization program of more than 20 years has been realized through 55 standardization mandates from the European Commission, which have involved more than 80 CEN technical committees. This makes the construction sector, by far, the largest sector in CEN.

CEN standards for the construction sector (2010)

In addition to the product standards, CEN has received standardization mandates from the European Commission regarding construction works and general aspects of safety:

o Sustainability: “Development of horizontal standardized methods for the assessment of the integrated environmental performance of buildings” (EC mandate 350).

o Energy performance: “Elaboration and adoption of standards for a methodology calculating the integrated energy performance of buildings in accordance with the EPBD (Energy Performance of Buildings Directive)” (EC mandate 343).

o Dangerous substances: “Emission to indoor air and release to soil, surface water and ground water” (EC mandate 366). It is to be noted that, in the new CPR, the “declaration of performance” required for every construction product will have to include the hazardous substance information required by the REACH regulation.

o Fire safety: “Evaluation of construction products in respect of their reaction to fire” (EU mandate 88), “Evaluation of construction products and elements in respect of their resistance to fire” (EU mandate 117) and “Fire alarm/detection, fixed fire fighting, fire and smoke control and explosion suppression products” (mandate 109).

o Eurocodes: “Agreement between the EC and CEN concerning the work on Eurocodes for the design of building and civil engineering works” (BC/CEN/03/89).

Eurocodes

In this last case, the European Commission took already the initiative in 1975 to establish a set of harmonized technical rules with the aim to eliminate

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technical obstacles to trade, which led to the first generation of European codes in the 1980s. This work was transferred in 1989 to CEN/TC250 “Structural Eurocodes” in order to provide them with a future status of European Standard (EN).

The second generation of Eurocodes were published in 1999 as 62 pre-standards (ENVs) and after a period of experimental use in the Member States, on the basis of the comments received, they have been converted into 58 European Standards (ENs) published in 2010. There are still “Nationally Determined Parameters” for which the ENs are giving recommendations, but it is left to the National Standardization Bodies to publish National Annexes (NA) with national choices for each of them which may differ from the EN recommendations. It is to be noted that, even if individual Eurocodes are devoted to specific structural materials (concrete, steel, timber, masonry, etc.), these have been drafted in order to correspond to the same safety level, and they may therefore be considered as a whole set of performance-based calculation methods.

A third generation will be prepared in 2011-2015 (EC mandate 466), extending to other structural materials, such as glass, fibre-reinforced polymers or tensile membranes, and with the aim, strongly supported by the European Commisison, to remove all the differences between the NAs, except those which may be justified by natural causes (climate, seismology, etc.) or those which express overall performances of construction works, such as partial safety factors, which remain within the jurisdiction of the Member States.

Regulations

The first construction regulation in history was the Hammurabi code dating from 1760 BC: it covers safety of persons as well as safety of goods, and fixes already performance-based requirements, together with (rather extreme!) penalties in case of failure.

Since 1804, article 1792 of the Civil Code established by Napoleon, which is still the basis of the legal systems of several European countries, fixes the performance requirement as a 10-years liability of architects and contractors, but leaves to the Courts of Justice, not only the fixing of the penalties, but, before that, the evaluation of the responsibilities on basis of the “good practice” at the time of construction.

Among the rules of good practice referred to in the Jurisprudence of the Courts, the Eurocodes will become, from now on, the dominating reference (but not the only one possible) for the stability and mechanical resistance of structures.

In Belgium for example, besides specific regulations on fire safety, dangerous goods and electrical installations, article 1792, as it is, is still the only general construction regulation, and this leaves an

Applicability of standards (calculation methods e.g. Eurocodes)

optimal freedom and a full responsibility to designers.

Other European countries have established more detailed Building Regulations by law, and these will have to be adapted in order to comply with the Eurocodes, which will then become compulsory in these countries.

The universal nature of the Eurocodes means that they can be completed with national regulations and local customs. Regulations exist because there are those who will do “any odd thing” and against whom society believes should take precautions in the form of safeguards. Regulations are the expression of a culture at a given moment, and should represent the minimum consensus in the public interest. Standards are clearly very useful as a common reference tool for all interested parties. They must exist, but they should not in the least diminish the responsibility of the person who applies them, and it can be very dangerous to transform them into regulations, so that thought is dispensed with, and an attitude of “if it's in compliance, it's okay!” prevails.

Conclusion

It is to be emphasized that the standardization work on European level is bringing much more than the addition of national contributions: by gathering together the best expertise available throughout Europe on each specialized domain, new developments are possible which can’t happen when these experts work separately in their country.

When starting a new project team of the European Coal and Steel Community, J. Monnet used to say at the first meeting: “There are two categories of human beings: those who want to be someone, and those who want to do something”. And he added: “If you are from the first category, there is no room here for you!” This “principle” speaks obviously to the mind of any engineer. And in his Memoirs, J. Monnet further wrote: “Beyond the defence of national positions, something new and strong comes into living within the team: it’s the European spirit which is the fruit of the work together and, above all, of the need to come to a common conclusion after the discussion”.

Pierre Spehl senior civil engineer of SECO, Brussels; honorary Professor of Université Libre de Bruxelles and Ecole Nationale des Ponts et Chaussées, Paris

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CEOS.fr - Behaviour and assessment of special construction works: concrete cracking & shrinkage

Background

CEOS.fr, coming from a French initiative, is a research project on the behaviour and assessment of special construction works (in particular structures with thick walls or girders) as regards cracking and shrinkage of concrete. The kick-off meeting was held in Paris on the 11th of April 2008.

The purpose of the research is to establish refined models concerning the development and the evolution of cracks in special concrete members with the objective to propose to the technical community a better understanding of phenomena and to bring a scientific contribution to the evolution of design codes, in particular design standards like Eurocode 2.

The organisation of the project, based on the active participation of several partners, is composed of a steering committee, including P. Labbé (Chairman), J. Mazars (scientific director), P. Bisch (technical director), D. Chauvel (management officer), C. La Borderie (modelling programme), J. Cortade (engineering programme) and L. Demilecamps (experimental programme). It is also composed of a scientific and technical committee and an international expert panel in charge of the periodic evaluation of the research. The members of the international expert panel are Prof. J.-A. Calgaro (France), Prof. M. Fardis (University of Patras, Greece), Prof. G. Mancini (Chairman of CEN/TC250/SC2 – Eurocode 2, Politecnico di Torino, Italy) and Dr. A. Pinto (Joint Research Centre, Ispra, Italy). The workshop organizing committee includes J. Mazars (Grenoble-INP, chairman), C. Rospars (IFSSTAR) and C. Bernardini (IREX).

In the context of the CEOS.fr research programme, “special” structures are those which are not covered by the current engineering practice, either because their dimensions are unusual (in particular very massive structures) or because of unusual serviceability requirements (life duration, leak tightness, etc.), or because of special requirements relating to the protection against external threats or hazards, or for any similar reason. In most encountered cases, addressing the design of such structures does not imply only discussing their strengthening capacity, but also describing expected crack patterns.

Crack formation is a complex mechanical phenomenon, very difficult to model. In the current engineering practice (such as for instance codified in the Eurocode 2), crack width and crack spacing are estimated through formulae that give very rough results and which are not satisfactory for thick walls. Moreover, using design codes for thermo-hydro-mechanical loads is difficult because description of data and/or methodologies are not easy to understand. Thus there is a necessity for improving crack modelling techniques for practical engineering purposes.

In this context, the general objective of CEOS.fr is to

improve significantly engineering practices for assessing crack patterns of concrete structures and predicting the expected pattern under anticipated conditions. This general objective is detailed in three areas, corresponding to three different types of physical phenomena to be considered and modelled.

o Cracking under monotonic loading: the purpose is to calibrate appropriate methods and to define their field of applicability. It is anticipated that new methods and formulae will be proposed, calibrated for special structures.

o Thermo-hydro-mechanical behaviour: under this title different phenomena generating strains will be considered and studied, in particular: early age behaviour, different types of shrinkage, consequences of long-term drying, boundary conditions, etc.

o Seismic and cyclic loads: this area is connected to containment reliability and to other safety considerations (such as anchoring of equipment), either during the seismic transient or after the event. The cumulative damaging effect of load cycles will be considered.

Expected progress should provide engineering companies with more efficient, accurate and reliable engineering tools for the description of crack patterns. It is anticipated that these tools will consist of both post-processors of finite element computer codes and appropriate formula to be included in design codes, and more specifically in Eurocode 2.

The first evaluation workshop

The research programme includes several steps. A first evaluation workshop took place in Paris on 28-29 May 2009. Several presentations showed that:

o the research is of major interest for the design of concrete structures;

o the research teams are undoubtedly motivated;

o the work which has been carried out up to now is of high quality;

o there is a real will to contribute to the evolution/improvement of design codes in this always controversial topic.

The research, managed at present by the French organisation IREX (Institut pour la recherche appliquée et l’expérimentation en genie civil – Institute for applied research and testing in civil engineering), will acquire an international dimension via a participation to the fib (Fédération internationale du béton-International federation for structural concrete) activity and subsequently the establishment of proposals in the framework of further evolution of the Eurocodes, and

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more specifically Eurocode 2.

From a scientific point of view, the expert panel recommended to go into depth in some important aspects like durability, combined effects of concrete creep and shrinkage, effects of cyclic loading, etc. Sustainable construction will be of major importance in the future, and the present research is fully in line with the objectives defined by the European Commission.

Moreover, in order to open up new relations with the international community it was suggested to organize new workshops at European level so as to exchange ideas and results with the major teams on the subject.

The second workshop ConCrack1, 2009

The workshop “Control of Cracking in Concrete Structures” (ConCrack1), was organized in Paris on the 10th and 11th of December 2009. The workshop was attended by 66 participants from 14 countries. 21 contributions by international experts were presented, covering the fields of engineering, experimental and numerical approaches of concrete cracking. Participants expressed their interest in the matter discussed during the workshop and their wish that a framework is established to pursue exchange of views on the subject of concrete cracking.

The workshop was an occasion to present new experimental data (relating for instance to early age behaviour, restrained shrinkage, effect of stirrups and statistical analysis) and to exchange ideas on them. Participants expressed the wish that experimental outputs be collected in a comprehensive data base and supplemented at different scales for complex mechanical loading cases and in the field of thermo-hydro-mechanics.

New developments in modelling techniques were also presented relating to:

o micromechanical models (homogenisation approach, multi-phase models, meso-models, rough crack contacts, etc);

o continuous models (multi-physics coupling, continuous vs. discrete models, etc);

o numerical techniques (discrete elements, X-FEM, special elements with embedded discontinuities, solver event by event, etc);

o reinforced concrete modelling (bound models, homogenisation approach, etc).

A common view of the participants was that modelling techniques should be developed at different scales, that they should be improved so as to be more robust and simple and that their sensitivity to input data, including statistical variability, should be established.

Members of the CEOS.fr International Expert Committee were invited to participate in a panel discussion to draw conclusions from the workshop. It was first stated that the international community shares the views that current

engineering practices for assessing crack patterns of concrete structures are poor and that there is a necessity to improve them significantly. The French initiative CEOS.fr is a first step in this direction, which should be developed at an international scale.

The workshop can be regarded as the starting point of an international network of scientists and engineers interested in such developments. The initiative of an international benchmark based on CEOS.fr experiments was highly appreciated by the participants and regarded as an opportunity to strengthen this network.

Sustainability of the CEOS.fr network could be established at a European scale by different means to be considered in the range of possible frameworks proposed by the European Community: European Construction Technology Platform, Marie Curie networks, Initial Training Networks, Industry and Academia Partnership Pathway.

It was acknowledged that works carried out in France under CEOS.fr are of utmost interest for the international community. Consequently, it was decided, based on the experience driven from CEOS.fr, to organize an international benchmark dealing with the modelling of the behaviour of the mock-ups tested (monotonic and cyclic loading on shear walls and large beams with prevented or free shrinkage).

French experts were invited to consider an extended and more active participation in the fib activities relating to the development of future building codes, so that the community takes benefit of ideas and results currently developed and obtained in France.

The third workshop ConCrack 2, 2011

Between the second and the third workshop, many experiments were organised to provide basic data to be compared to results of calculations with several models. Based on these experiments, the international benchmark ConCrack deals with the modelling of the behaviour of the tested mock-ups.

Shear wall specimens

The aim of this sub-program was to get data on cracking mechanism and pattern when a wall is subject to monotonic or alternate loading applied within its symmetry plane. The overall dimensions for the testing speciments were 4.20×1.50×0.15 m (length × height × thickness) and the scaling was 1/3.

Two load cases were selected for the purpose of this benchmark (same geometry and reinforcement scheme):

1. specimen under monotonic shear loading (test 1)

2. specimen under cyclic shear loading (test 2)

Large beam specimens

Large-scale specimens (L=6.10 m, l=1.60 m, h=0.80 m) have been designed to check the influence of different

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Testing bench (top) and dimensions (bottom) of the shear wall specimens

"second order" parameters. Once cast, two procedures were used:

o Free-shrinkage beams were allowed to set free, slightly protected against the major climatic conditions, for about four weeks. Then they were placed on a bending bench, tightened to it by prestressed bars and brought to the bending limit state by two rows of four 100 t jacks.

o I-shaped beams experience restrained shrinkage due to struts and, as for free shrinkage beams, they were tested at the bending bench after 4 weeks.

The following teams participated to the benchmark:

o G. Liliu, C. Frissen, C. Damoni, B. Belletti; TNO Diana BV (NL), University of Parma (IT)

o G. Meschke; Rhur-University Bochum (DE)

o V. Cervenka, D. Pryl; Cervenka Consulting (CZ)

o F. Vecchio, S.-C. Lee; University of Toronto (CA)

o M. Pimentel, R. Faria, M. Azenha; University of Porto, University of Minho (PT)

o W. Arnold, T. Jones; ARUP (UK)

o M. Jirasek, P. Havlasek; Czech Technical University in Prague (CZ)

o E. Schlangen, B. Savija; Delft University (NL)

o M. Aschaber, G. Hofstetter; University of Innsbruck (AT)

o D. Linero, A. Huespe, X. Oliver; University of Colombia, University of Santa Fé (AR), Polytechnic University of Catalonia (ES)

o P. Mark; Rhur-University Bochum (DE)

o B. Schrefler, G. Sciumè; Padova University (IT)

o D. Kuchma; University of Illinois (USA)

o S. Billington & Y. Dang; Stanford University (USA)

o C. Burns; ETH Zurich (CH)

o T. Jefferson, P. Lyons; University of Cardiff & LUSAS (UK)

o A. Marí, J. Bairán; Universitat Politècnica de Catalunya Barcelona (ES)

o H. Nakamura, Y.Yamamoto; Nagoya University, National Defence Academy (JP)

The benchmark was organized in a blind way (experimental results were not given). Starting June 2010, eight months were given at the participants to do the work. Afterwards it was possible for them to consider experimental results in order to prepare their workshop presentations.

A 120-pages synthesis report has being drafted, based on the experimental and the numerical results. It allows pointing out the capability of models to forecast cracking phenomena both for mechanical load and for THM loads at early age.

However, the purpose of this benchmark was not to achieve a ranking of the work of the different teams, but rather to highlight the ability of particular types of modelling strategy. In modelling there are various options linked to the model and to the orientation of the calculation (type of discretisation, boundary conditions, etc). It is the whole which leads to the relevance or not of the results.

As a general conclusion on the results for shear walls and beams, it is very encouraging to see the quality of the simulations. They appear to be operational to model complex coupled problems. A problem that does not appear totally solved is that of good estimating indicators for cracking, especially in terms

Scheme of the test on large beams Geometry and reinforcement scheme for the free-shrinkage specimens

I-shaped geometry for the restrained-shrinkage specimens and restrain system

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of opening. However advanced research on this subject is in progress.

Key findings from the round table at the end of workshop

It is recommended to:

o Strengthen the involvement of French scientists and engineers in the sub-groups of fib, for example in the TG4.1, in order to form a sub-group of actors including French experts and some benchmark participants to percolate the CEOS.fr results in the work of fib.

o Work further towards the approximation of the tools from the academic world and those of the engineering world. Relevant and simplified simulation tools need to be developed.

o Take advantage of the synergy created by CEOS.fr to prepare the future research programs. Themes such as the variability of parameters, treatment of uncertainties and the introduction of probabilities in the analysis of thermo-hydro-mechanical behaviour of concrete structures appear appropriate.

Decisions from the meeting of the CEOS.fr International Committee

Following the benchmark, the web site concrack.org becomes a platform for exchange of information between participants and members of the national project CEOS.fr.

The synthesis of the benchmark and the presentations of participants in the ConCrack2 workshop are available online.

In addition, all results (benchmark and post benchmark, including those from CEOS.fr members) will be published in a special issue of the European Journal of Environmental and Civil Engineering at the beginning of 2013.

A proposal is made to participants who wish to continue the calculations to other tests performed in the context of CEOS.fr.

Finally, it was decided to support the organization of a new workshop, ConCrack3 (15-16 March 2012). The objective is the presentation and the analysis of the guide on the "control of cracking at young age of mass concrete structures" realized in Japan as part of a Japan Concrete Institute (JCI) working group chaired by Professor Sato (Hiroshima University).

Jacky Mazars Grenoble Polytechnic Institute Jean-Armand Calgaro Chairman of CEN/TC250

More information at: ceosfr.org

Second International Workshop “Design of concrete structures and bridges using Eurocodes”

12 - 13 September 2011, Bratislava, Slovakia

The workshop was organised by the Slovak University of Technology in Bratislava, Faculty of Civil Engineering, in cooperation with the Czech Technical University in Prague, and the Technical University in Vienna.

Modern bridge in Slovakia

The workshop focused on the application of EN 1991-2, EN 1992-1-1 and EN 1992-2, since these standards have been introduced and accepted as national standards in many European countries and there is already some practical experience with their use.

The workshop comprised a series of keynote lectures:

o Background to EN 1991-2 – Traffic loads on road and railway bridges, Jean-Armand Calgaro

o Improvements of the strut-and-tie method in EN 1992-1-1, Tony E. Jones

o EN 1992-2: give because a why, Gabriele Bertagnoli & Giuseppe Mancini

o Design of structures and the contribution of codes, Konrad Zilch

o Development of design of concrete construction – Eurocode 2, Jaroslav Procházka

The remaining of the workshop was organised in sessions dedicated to specific topics:

o Background, future and proposal of major changes;

o Eurocodes vs. national standards and National Annexes;

o Design according to EC2;

o Experience with bridges design.

More information at: http://enconcrete.sk