THE MILLAU VIADUCT, Slides of Construction

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BARTLETT SCHOOL OF PLANNING

LATTS

France

Millau Viaduct

Viaduc de Millau

This report was compiled by the French OMEGA Team, Ecole Nationales Ponts et Chaussees, Paris, France.

Please Note: This Project Profile has been prepared as part of the ongoing OMEGA Centre of Excellence work on Mega Urban Transport Projects. The information presented in the Profile is essentially a 'work in progress' and will be updated/amended as necessary as work proceeds. Readers are therefore advised to periodically check for any updates or revisions.

The Centre and its collaborators/partners have obtained data from sources believed to be reliable and have made every reasonable effort to ensure its accuracy. However, the Centre and its collaborators/partners cannot assume responsibility for errors and omissions in the data nor in the documentation accompanying them.

H OPERATION

I CONCLUSION AND MAIN ATTRIBUTES OF SUCCESS

J BIBLIOGRAPHY

K GLOSSARY

List of figures

• Figure 1: Millau Viaduct.........................................................................................................
• Figure 2: the French Highway Network (free highways in black)
• Figure 3: the site
• Figure 4: the viaducts of the A75
• Figure 5: technical attributes of the Millau Viaduct
• Figure 6: view of the Viaduct from the town of Millau...........................................................
• Figure 7: access road reforestation
• Figure 8: the four alternative routes.....................................................................................
• Figure 9: the high and low solution
• Figure 10: five proposals for the Viaduct
• Figure 11: the piers issue
• Figure 12: the piers issue
• Figure 13: actual form of the piers and pylons continuity
• Figure 14: the deck issue
• Figure 15: actual form of the deck
• Figure 16: the curve of the Viaduct......................................................................................
• Figure 17: the curve of the Viaduct......................................................................................
• Figure 18: the concession offers
• Figure 19: construction principle of the steel deck

Equipment took the decision to transfer responsibility for the project to the private sector.

1999/2000 Procurement Organizing an international tender for a BFOT type of procurement, a concession where the private contractor is bound to finance, build and operate the designed infrastructure.

23 November 1999

Public enquiry Second DUP : the first inter-ministry decree of 1994 is amended in order to comply with concession conditions and allow a toll system for the Millau Viaduct.

March 2001 Procurement EIFFAGE won the bid for the delivery of the Millau Viaduct_._ 30 May 2001 Procurement Signature of the concession contract.

8 October 2001 Procurement The Council of State approves the project and the attribution of the contract to EIFFAGE via a Ministry Decree. Procurement Decision to build the Viaduct in metal rather than concrete (beton). 10 October 2001 Project delivery/ construction

Beginning of the construction phase.

20 February 2002

Control of construction

Establishment of expert committee of the ACDC chaired by Jean Francois Coste.

14 December 2004

Project delivery/ construction

Opening of the Millau Viaduct and beginning of the operation phases a few days later.

Sources: Ministère de l‟Equipement (2004) Le Millau Viaduct, un ouvrage exceptionnel initie par le Ministère de l’Equipement. Dossier de presse. http://www.environnement.gouv.fr/IMG/pdf/millau_cle148b14.pdf (17/02/2010)

CEVM (Compagnie Eiffage du Viaduc de Millau) Historique d’un projet né en 1987. Quelques étapes significatives d’un grand viaduc à Millau. Unpublished document.

Coste J-F (2009) The Millau Viaduc, Royal Aeronautical Society, 20 October 2009.

A PROJECT INTRODUCTION

The Millau Viaduct is a seminal civil engineering structure on the Motorway A75, linking Clermont-Ferrand to Montpellier. It belongs to the same family as the Normandy Bridge: the family of bridges with multiple cable–stayed spans. Its civil engineering structure was originally designed by the same author, the French engineer Michel Virlogeux, before being improved and enhanced by the collaboration with Norman Foster & Partners, the British architectural practice.

Type of project and originality of the process

The Millau Viaduct is the fruit of a long process initiated in 1987, which ended in December 2004 with the delivery of the bridge. It presents different points of interest from the point of view of MUTPs.

“The Millau Viaduct is not only considered as an exceptional piece of work from the technical perspective but also comprises several innovations in terms of processes and procedures from the choice of the route, the design, the evaluation prior to the BOT contract (a concession type) to the elaboration of the financing scheme and the negotiation process between the shortlisted private contractor and the public administration.”

Source: Translated from Coste, J. F. (2005)

One of its special features is linked to the process applied to this project: it has been, firstly, the subject of nearly twelve years of in-depth studies led by the Roads Directorate ( Direction des Routes ) of the Ministry of Transport and Construction ( Ministere de l’Equipement ); the technical services of the administration (Setra, AIOA DDE, etc.) then checked the feasibility of a single civil engineering structure crossing the Tarn river, and several architects and engineering offices were invited to enter a competition, to widen the search for possible alternative solutions. It was at the end of this search, under the lead of a panel of international experts, that the solution of a multiple cable-stayed span structure was decided upon.

The technical design is the product of Norman Foster & Partners, the British architectural practice, and SEGELERG-EEG-SERF. Yet, the design consists of an improved version of the early work of the French engineer Michel Virlogeux, who gave reality to Millau as a multiple cable-stayed span structure and who cooperated with Norman Foster during this phase.

has been clearly planned for the purpose of regional development: opening up the Central Massif and the multiplicity of access in the crossed areas for the purpose of improving their accessibility. This motorway benefited also from the strong political will, of national figures such as M. Valery Giscard d‟Estaing, ex-President of the Republic and deputy Mayor of Clermont-Ferrand, but also at the local level.

Free access to motorway versus toll on the Viaduct

The objective of accessibility also means free access to the motorway. The concept of the Millau Viaduct developed during the 1980s in the context of the A75 under the current policy framework for expanding the highway network in France. In contrast with the rest of the French national network (see below), the A75 is a free highway. Yet the Millau Viaduct is all the more unique in that it represents the only toll-infrastructure on the A75, a specificity explained by the choice of delivering the infrastructure under a concession/BFOT type of procurement.

Integration and environmental protection

The A75 has been also designed with special care for environmental protection: it is the first motorway which benefited from the application of the policies of „1% landscape and development‟ and „villages stop‟ ( villages etapes ) launched by the government.

Beyond the objectives pursued for the A75, the Millau Viaduct has been also designed to solve the problem of the huge summer traffic jam in Millau. It is designed as a Millau bypass but with possible access to the city.

To summarize, the development of the A75 connecting Clermont-Ferrand to Beziers, particularly the Millau bypass, is integrated into a Road Policy aiming at:

 supporting spatial and territorial development;  improving safety and security issues, and;  paying particular attention to the protection of the environment.

In addition, the A75 had been subject to the traditional public enquiry and a form of participative process which involved local politicians and stakeholders, an odd practice at that time. The decision-making process was greatly influenced by such typical context, confirming the interesting character of the Millau Viaduct.

Source:

Figure 2: the French Highway Network (free highways in black)

Source: Coste (2009)

Spatial location of the Viaduct

Taking all these issues into account, the choice of spatial location for the Viaduct was not insignificant. The Viaduct, as we have seen, belongs to a „chain‟ of civil engineering structures. It is also deeply linked to the dilemma met in the definition of the route, regarding both the bypass location and the crossing of the Tarn River. The location also contributed to explain the technical attributes, as will be seen below.

Briefly, the Millau Viaduct is the greatest bridge on the A75 highway, bypassing the Tarn Valley between the Causse Rouge in the north and the Causse de Larzac in the south. The bridge is located 5km west of the city of Millau and is the last part of the Clermont- Ferrand/Beziers highway link.

Source:

Figure 4: the viaducts of the A

A75 motorway Clermont-Ferrand Béziers 340 Km

A75 motorway Clermont-Ferrand Béziers 340 Km

Viaduc de la Violette

Viaduc de la Truyère

Viaduc du Rioulong Viaduc du Piou

Viaduc de La Planchette

Viaduc de Verrières Viaduc de La Garrigue

Viaduc de Millau

Source: Coste

Technical attributes and project challenges: from Normandy Bridge to Millau Viaduct

The choice of location and of design and civil engineering methods for the Millau Viaduct explain some of the technical challenges presented by this civil engineering structure.

Michel Virlogeux, civil engineering designer for the Millau Viaduct as well as for the Normandy Bridge, explained in our interview with him and in an article (M. Virlogeux 2001) the specific problems of bridges with multiple cable-stayed spans.

On the one hand they can be used for long spans, and rapid progress has been made in span length in recent years: “Cable-stayed bridges now compete with suspension bridges for spans between 700 and 1200, or even 1500m. The erection of the Normandy bridge was a major step in this field… (Nevertheless) the Normandy bridge is no longer the longest cable- stayed span in the world. Since May 1999, the world record belongs to the Tatara bridge, Japan, a very elegant structure”. As this author underlines, the cable stayed solutions can be both efficient and elegant. (Source ).

On the other hand, they are confronted with some constraints. “The design of long span cable-stayed bridges is dominated by the resistance to turbulent wind dynamic effects and by aerodynamic stability. Streamlined box girders, inspired by the English suspension

bridges and the Normandy Bridge, constitute the best technical solutions to these problems” (Virlogeux M. 2001, pp62-63). Another problem is that of cable vibrations: “Despite better understanding of the phenomena that produce such vibrations, one cannot consider the problem solved, as some points are still controversial. On the other hand, it is known how to master cable vibrations by different types of countermeasures” (Virlogeux M. idem). Different solutions can be found to these constraints. “The best solution and the most elegant, is to distribute rigidity between the different structural members (the deck, piers and pylons) in order to balance bending effects produced by asymmetric live loads and to limit deflections.” (Virlogeux M. idem p.70).

According to these previous considerations, the Millau Viaduct could seem very ambitious: it is about 2.5km long, with the road passing 270m above the River Tarn.

It is made of steel with a maximum height of 343m at the top of the pylons. A multiple cable- stayed span structure was selected due to aesthetic considerations, giving prominence to a very light deck and piers soaring up towards the sky. However, the Viaduct comprises seven piers, that is only seven points to lean on. Going further, the Viaduct constitutes an exceptional bridge with the following characteristics:

 a length of 2,460m comprising:  six spans of 342m length;  two side spans of 204m length.  seven piers, P1 to P7:  the highest, named P2, measures 245m and is 270m above the Tarn River.  two Abutments (C0 and C8).  it required 85,000 m^3 of concrete.  the steel deck is:  32.05m large, entailing:  a 2x2 lane highway with a three metre shoulder;  wind screens to protect the vehicles;  4.20m thick;  and weighs 36,000 tonnes, four times the weight of the Eiffel Tower.

Source: Coste (2009)

Figure 5: technical attributes of the Millau Viaduct

Source: Coste (2009)

initially, the Millau Viaduct was treated as any A75 infrastructure under the authority of the National Road Administration.

Concurrent with the development of the project, the National Road Administration in charge of developing the project went through internal changes. In 1989-1990 Jean Berthier, the head of the Road Directory, who decided the actual route of the Viaduct, left the administration. He was succeeded by Christian Leyrit, who supervised the whole delivery of the Millau Viaduct from conception to opening. Patrick Gandil replaced Christian Leyrit for the operation phases. Among other decisions, Christian Leyrit took responsibility for selecting the design of the Millau Viaduct via an international competition comprising several teams of engineers, architects and representatives of local governments. Yet such a decision constitutes an important turning point in the design of bridges in France, especially compared to the Normandy Bridge, which was designed within the Administration by SETRA, a public consulting and engineering office under the direct authority of the Roads Directorate. In other words, it was not very common to subject SETRA‟s expertise and projects to external opinions and experts. Indeed, the Millau Viaduct represents the first time that the design of a project would depend on a competition, a decision greatly justified by the scale of the project and its ambitious character.

Subsequently, SETRA and the Roads Directorate defined five „best options‟ for the future Millau Viaduct and then invited five integrated engineer-architect teams to compete by elaborating on each option. These five options emerged from a „brainstorming‟ process organised within SETRA and calling on international experts. The competition was launched in 1995 and led to the selection of the project of the British architect Sir Norman Foster in

1996. The project is derived from the cable-stayed solution originally proposed by Michel Virlogeux, who had also designed the Normandy Bridge when he worked for SETRA. However, this design did not prescribe the construction method, namely whether to build the bridge in steel or concrete. While both solutions were possible, at that time, the Millau Viaduct was intended to be in concrete, not in steel. Later, when the project entered the realisation phase, the decision to adopt the steel solution became a crucial factor in respect of avoiding construction delays and a preoccupation which cannot be isolated from the Viaduct‟s key enabling mechanism: the decision to entrust the private sector with the financing and delivery of the project.

Source: Compiled by the author.

Main actors (outside of the designers)

 The French State: the conceding authority, with its different missions of experts.

 The Arrondissement Interdepartemental des Ouvrages d’Art (AIOA) was given responsibility for monitoring the project by the State. It reports to the Infrastructure Directorate of the Aveyron, which manages the construction works of the A75.

 The local government authorities: The commune of Millau and the Grands Causses Grouping of Communes.

 EIFFAGE: The third largest construction group in France:  CEVM: The concessionary structure, a subsidiary of EIFFAGE;  EIFFAGE TP;  SETEC: an independent engineering office responsible for the MOE ( Maitrise d’oeuvre ).

Source: Ministry of the Equipment http://www0.planete-tp.equipement.gouv.fr/en/IMG/pdf/6_cle6a166b-8.pdf

Key enabling mechanism

The decision to procure the Millau Viaduct under a concession/BFOT scheme was made in 1998 by the Communist Minister of Transport, Jean-Claude Gayssot. The decision relates to the lack of public funds available to provide the A75 missing link, namely the Viaduct, which represented an investment of approximately 2 milliards of francs (about EUR 400m). Again, in the initial planning stage, the link was conceived of as a free highway without any toll. As the public budget could not accommodate such expense the only way to avoid postponing the project delivery – and its economic benefits – was to find a source of alternative funding. That is why the Millau Viaduct came to rely exclusively on private finance. More precisely, the initial investment relied on the corporate funds of the Compagnie Eiffage which then re-negotiated a loan from the banks at a lower interest rate, once the construction risks disappeared (Coste, 2006).

Source:

The tendering process was launched according to European Law in November 1999. In 2000, the Compagnie Eiffage won the bid. Unlike his competitors organised in consortia, M. Jean-Francois Roverato, the CoE of Eiffage, bid alone with subsidiary companies. Among other constraints, an organisational structure similar to the traditional French Maitre d’Ouvrage (MOA) and Maitre d’Oeuvre (MOE) structure was required. Within the concessionaire organisation, the client role ( MOA ) was taken by CEVM, the future operator of the infrastructure, and the contractor role ( MOE ) by SETEC. Reciprocally, the role of the Administration, namely the state, has changed over the delivery of the Viaduct and is confined to the control of the process.

Source: Contrat de concession?

Project outcome

From the procurement and delivery perspective, it could be mentioned that in such a large scale project, increasing costs and delays over the construction phases are the norm rather than the exception (among many others see Miller & Lassard, 2000;^1 Flyvberg, et al, 2003^2 ). However, in the specific case of the Millau Viaduct, the project was delivered on time and within budget, that is three months in advance of the initial plan. From this perspective, the project constitutes a success all the more exemplary because it relied on a concession scheme.

This procurement choice could be viewed as a specific contractual form of Public-Private Partnership (PPP) arrangements, which raise the issue of the allocation and management of risks and uncertainty between the state, as the public client, and Eiffage, the contractor. Indeed in France such arrangements raise a general issue concerning the conception, design and construction of such infrastructure: how to avoid the multiplication of competitive tenders favouring economical but trivial structures, easy to build and without risks? The constraints of the market and financing concerns could rule out original solutions and limit

(^1) Miller R, Lessard, DR (2000) The Strategic Management of Large Engineering Projects: Shaping

Institutions, risks and governance. 2 MIT Press. Flyvbjerg B, Bruzelius N, Rothengatter W, (2003). Megaprojects and Risk: An Anatomy of Ambition. Cambridge University Press

Source: Offre de concession d‟Eiffage- extraits concernant les concepts paysagers et la restauration du milieu vegetal.

Figure 6: view of the Viaduct from the town of Millau

Source: PCM (2005)

Figure 7: access road reforestation

Source: PCM (2005)

Still, it is important to stress that the cooperation between the concessionaire, the state and the local authorities persists beyond the delivery of the project: for example in the case of extreme weather conditions such as snow fall, the actors have to organize themselves in close collaboration to provide – and fund – the required safety measures. Yet to some extent the concessionaire EIFFAGE became an important actor in the life of the local communities.

Besides the indisputable evidence of the positive effects of the Viaduct on local economic development some deplore insufficient leadership from the state at the local level, as greater benefits could have accrued if the process had been further monitored and managed.