A linking structure on the Boulevard Périphérique between Paris and Aubervilliers, the Claude Bernard overpass, which bears the distinctive stamp of the DVVD architecture, design and engineering agency, has been in service since 2nd October 2015. Sympathetic to its environment, this sculpted structure, formed entirely of curves, is a strong landmark in the changing panorama of the capital.

Simple as a brushstroke, slender in form, the Claude Bernard overpass elegantly spans the Boulevard Périphérique between Aubervilliers and Paris. This arched timber structure, nearly 100 metres in length, connects the Parc du Millénaire to the Claude Bernard urban development zone, the very embodiment of an emblematic site. In this rapidly-changing district, a flagship for development policy in the north-east of the Ile-de-France, office blocks and residential buildings rub shoulders with a cinema, a nursing home, a nursery, a school, sports facilities, a multi-mode transport hub (incorporating the RER E rapid transit line, four bus routes, and routes 3 and T8 on the tram system), a park and a shopping centre. This developmental diversity has dictated a fresh approach to the consideration of urban density, multi-functionality and compactness, further accentuated by an overall environmental approach which is consistent with the objectives of the climate action plan of the City of Paris. One change leads to another: a change in the status of the city ring road, now conceived as an urban boulevard. The scale of this challenge was therefore to support this local dynamic through the provision of an overpass. More than just a bridging structure, this needed to be a unifying and symbolic feature. This brief has been perfectly realized by the architects at the DVVD architecture, design and engineering agency.

Technical prowess
A technical project such as an overpass involves constraints which are not run-of-the-mill. The requirement for the least possible disturbance to vehicle traffic, for example, dictated an unusual installation procedure: once the pile-mounted abutments with their associated stairways were in place on either side, the central section, fully-fitted with its timber cladding and decking, was mounted on its permanent supports in a single night. This arduous operation involved the deployment of a mobile crane of exceptionally high capacity, of a virtually unique type in Europe. This crane was positioned on the outer Boulevard Périphérique, fitted in record time with the numerous counterweights required to increase its load-bearing capacity, completed the lifting operation, then disappeared, allowing traffic to resume under a new crossing structure. With the same idea of optimization in mind, the definition of the geometry of the overpass as a continuous arch, with no drops, and the design of its metal framework structure have been executed using sophisticated digital tools. The objective was to lighten its structure, optimize the budget, economize on raw materials and facilitate the lifting operation. The scheduling of the night-time lifting operation, on 14th May 2015, was planned minute-by-minute by the prime contractor and the project contractors. The installation of the walkway involved the simultaneous closure of carriageways on the inner and outer Boulevard Périphérique for three hours – an operation which had never been undertaken since its opening. This precision-engineering project was conceived in partnership with the services of the City of Paris and the Prefecture.

A natural and easy-to-use connecting structure
The Boulevard is crossed between the Rue Lounès Matoub – on the side of the 19th arrondissement of Paris – and the roadway which runs between the buildings of the Parc du Millénaire in Aubervilliers, now made more accessible by this new strategic axis. The Claude Bernard overpass launches itself from the south, extending from the pedestrianized square which accommodates the cinema, inviting the user to sail over the Périphérique and make a gentle landing to the north, in a logical extension of the angle formed by the recently-delivered services building. The proposed route is simple, direct and clear for all pedestrians, who will instinctively use the broad-stepped stairways on either side of the overpass, or the landscaped ramps which offer easier access and the straightforward movement of traffic in both directions, for persons with reduced mobility, bikes or pushchairs.

“Our primary intention was to create a strong and continuous visual link between the two sides of the ring road. This argued naturally in favour of an arched structure, which is suggestive of walking, crossing, and a leisurely stroll.” Daniel Vaniche

Midway across, more generously-dimensioned plots provide rest areas and panoramic viewpoints. Once above the Boulevard Périphérique, the structure is conceived as a unifying space which accommodates bikes and pedestrians alike, in an arrangement where everyone can rub shoulders without impeding each other.  The rising curve of the walkway is matched by a variation in the planar profile of the decking, which allows a natural connection to be formed between the streets at either end, ensuring the continuity of both the landscape and the route employed. And again in the interests of natural extension, the overpass is built to a street-level scale: its dimensions ensure its approachability for pedestrians, making it a key element in the network which enhances the flow of traffic in this area. This contextual evidence reinforces both the visual and the spatial proximity of the two sides of the Boulevard Périphérique.

“This is primarily an urban project, ahead of any design or architectural features. A continuation of the existing street provides a link in the territorial network, delivering spatial and visual continuity.”

Daniel Vaniche

Technology and artistry go hand in hand
In order to reduce the height of the structure and its impact upon the landscape, and in the interests of a more subtle outline, the load-bearing structure has been conceived as two variable-inertia three-dimensional arches, which are concealed in the protective housing which serves as a safety barrier. This solution enhances the inertia of the structural beams and reduces weight. Ultimately, this optimized structure has a weight of less than 270 tonnes, thereby saving raw materials, reducing the ecological impact of the structure and allowing the latter to be lifted by crane. This design also allows the level of pedestrian traffic to be lowered by more than one metre. The structure is arranged on either side and not below the decking, resulting in a 20-metre ramp and six fewer steps on either side. Above all, a continuity in perspective is maintained from one side to the other, making the structure more urban in character and less imposing. The metal framework is concealed behind the protective timber cladding, which interacts with the light. Its transparency allows visual contact between pedestrians and drivers, while maintaining a degree of distance. This is a unique and identifiable design.

“The ramps are incorporated into the design of the linear forest, which enriches the district with a facility for an unexpected stroll.” Bertrand Potel

“The slatted timber cladding delivers the initial reassurance of visual density, followed by the surprise of its curvature, and ultimately its open views over the Boulevard Périphérique.” Bertrand Potel

A balcony over the city
The asymmetrical arrangement of the two structural arches breaks the monotony of the crossing, which is also highlighted by the pattern of the double-sided timber fretwork. At the centre of Boulevard Périphérique, the planks are taller and closer together, obstructing the harrowing views of the traffic 6 metres below. Pedestrians are thus provided with an enclosed interior place, with greater protection from noise, speed or pollution. Conversely, in the interests of transverse views from the Boulevard Périphérique and its borders, the more widely-spaced planking becomes transparent: the overpass is disembodied. This combination of contrast and expansion multiplies the interplay of light, thereby contributing to the dynamism of the structure. Through its successive filtering elements, the overpass opens up to the skies and the surrounding landscape, allowing the user to stroll, to stop at will, and enjoy a balcony over the city. An unprecedented panorama, further enhanced at twilight by the light fittings which are incorporated into the structure.

Its geometry, design and cladding make the Claude Bernard overpass an essential and key feature of this site, in both functional and symbolic terms. A capital structure.

Technical Data Sheet

Location: Paris (19th arrondissement)

Contracting authority: SEMAVIP

Architecture, engineering, design
DVVD : Paula Castro, Céline Cerisier, Vincent Dominguez, Toma Dryjski, Bertrand Potel, Louis Ratajczak, Daniel Vaniche,

Project Manager : Clément Carrière, Nicolas Didier

Contractors : Segex / Razel-bec (structural works), Viry (metal framework), Agrigex (landscaping)

Budget (design analyses and works) : 8,5 M € HT, 2012 values

Span excluding ramps : 98 metres
Span: 60 mètres
Width : 4 metres
Steelwork : 120 tons
Surface area : 392 m2

Timber decking and cladding 
Variety : Solid oak
Certification : PEFC
Origin: Ile de France

Competition : 2013
Design analyses : 2013-2014
Project : 2014-2015
Delivery : 3^rd october 2015

Overnight installation : 14th may 2015
Exceptional interruption of ring road traffic

6 Questions to François Dagnaud, from the contracting authority  SEMAVIP

What are your initial impressions of the installation of the Claude Bernard overpass?
The “landing” of the walkway, during the night of the 14th and 15th May 2015 and completed to a very tight schedule, was first and foremost a remarkable and historic spectacle, highlighted by the closure of the ring road for several hours, in an atmosphere which was both focused and frenetic. Technical engineering, accurate to the millimetre, has been employed in the service of urban ambition: crossing the ring road to connect two territories. I congratulate the staff of the DVVD agency for their remarkable work, but also the SEMAVIP, the contractors and the services of the City, who have given their utmost for the successful realization of this project.

How can you and would you define this overpass?
It is both a location – as a fine architectural object in its own right – and a link which interconnects and delivers a shared pulse to two districts of the city. In this mineral-dominated environment, the overpass provides a warm-hearted interlude. Apart from its aesthetic success, this is a physical emblem of the new face of the city, linking the modern districts of Paris and Seine-Saint-Denis.

What expected and unexpected repercussions have been experienced by the city since the commissioning of the overpass?
Opened during the 14^th “Nuit Blanche” arts festival on 3^rd October last, the overpass is entirely in keeping with the spirit which we are seeking to endow upon the Rosa Parks-Macdonald district: a 21^st-century district, resolutely focused on innovation, and in complete harmony with its industrial past. It is surprising to see how quickly local residents and workers have adopted this new crossing. Initially, the primary flux of users of the overpass was observed in the Aubervilliers-Paris direction. The UGC cinema in particular has been one of the beneficiaries of this dynamic trend. It is a genuine convenience for city-dwellers to be able to come and go, as they discover this new and richly-promising district. Subsequently, the opening of the Rosa Parks station, the installation of the Ministry of Justice in particular, and the arrival of new residents in the Macdonald buildings saw a reversal in this movement. It is impressive to observe the stream of users leaving the new station, before sweeping through the station concourse and entering the Parc du Millénaire. The transformation of the district is the result of a successful venture, combining residential, business and transport factors.

What do you think of the materials used by the DVVD agency?
In just a few years timber has become a fashionable material, with great promise for the future. The use of timber on this overpass makes complete sense, providing a warming presence and an anchoring point, making it possible to stroll just a few metres above the highway. This material naturally softens the interruption generated by the Boulevard Périphérique, is perfectly integrated in its environment, and echoes both the linear forest and its own artistic installation.

What do you think of the proposal of the DVVD agency, and what were you expecting from this type of project?
The overpass proposed by the DVVD agency provides a landmark which is visible, but in keeping with the scale of streets and residents. The fact that it has not been conceived as a monumental structure has made a difference. It softens the break formed by the Boulevard Périphérique, delivering a continuous and elegant design. The signature of the DVVD agency is identifiable but not intrusive, providing a crossing which is accessible to all, functional and well-integrated in its urban environment.

What feedback have you received from residents?
Residents have been impressed by the overpass, and have enthusiastically adopted this structure. It has already become the pride of residents, features prominently in the blogs of local inhabitants and in urban planning forums. Everyday users, particularly workers, have a less emotional attitude to this object, and are more likely to appreciate its practicality. We have heard some comments on the lack of visibility of the treads, the neutral shades of which make them difficult to distinguish from the risers. Some adjustments will need to be made, but the overpass has definitely won over its public.

4 Questions for the contractor Segex

What have been the major stages in the construction of the Claude Bernard overpass?
Nine steps can be identified:
– development of the project and the completion of construction designs
– construction of deep foundations (nine piles of diameter 1,200 mm under each of the four supports of the overpass)
– construction of concrete blocks for the overpass supports (9 x 9 x 0.8 metres)
– construction of supporting walls for the access ramps to the overpass
– in-plant prefabrication of the metal structure
– erection of the metal structure on a work site
– timber cladding of the structure
– installation of the overpass
– finishing operations and planting of vegetation

How would you define the Claude Bernard overpass?
This arched structure combines refinement and elegance, with the successful integration of the overpass into the linear forest landscape which flanks it, and the provision of a link between Paris and the municipality of Aubervilliers.

What were the technical challenges involved?
One of the particular features of this design is the dual curvature of the overpass, both in the plane section and in elevation (horizontal and vertical). This project also posed an operational challenge: the installation of the central section of the overpass, already fitted with its cladding, was completed in just a few hours, on the night of the 14th and 15th May 2015, in order to ensure the minimum disturbance to traffic on the Boulevard Périphérique, which was closed for the occasion, for the first time in 40 years. This operation involved the use of two mobile cranes of capacity of 700 tonnes. In total, the structure weighs over 270 tonnes.

How did collaboration with the DVVD agency proceed?
This was a full and comprehensive collaborative process, whether in the construction design phase or in the execution of the project. Our shared objective was invariably the ongoing identification of a solution – ever mindful of facilitating the work of the contractor and respecting the preferences of the architects – and working together for the achievement of a common goal.

5 Questions for the contractor Viry

What are the major stages in the construction process?
For the development of the Claude Bernard overpass, it was necessary for the components to be modelled in full, prior to any construction. By way of indication, the decking and cladding are comprised of over 10,000 components, all of which have been modelled. The production and assembly of the various components of the structure have then proceeded on the basis of these component plans. The entire overpass was then dry assembled in the Viry workshops. It was then dismantled in sections, then re-assembled on-site. In order to assist re-assembly, the workshop template was reused in order to permit the comprehensive control of the overall geometry of the structure. Finally, the time had arrived for the lifting of the structure and its end-to-end joining with the stairways. This operation was scheduled for completion in a single night.

How can you and would you define this overpass?
The overpass features surprising curvature and an austere profile. The continuity of its outlines makes it pleasant to approach and to cross. The weave of its cladding also provides transparency from the exterior, while maintaining a degree of opacity between the interior and the ring road. This timber cocoon of solid oak, a high-grade material, makes it possible for the user to forget that the ring road lies below, as they are crossing.

What have been the technical challenges for your company?
The key technical challenges have been of two types, but driven by a single imperative: the successful installation of an overpass with a 100-metre span, in a single night, over the busiest road route in Europe. The first challenge was the management of curvature, and the anticipation of the strain which would be sustained by the overpass upon installation. To this end, the structure was constructed in a reverse-bowed arrangement, and did not assume its final geometry until it was installed. The second challenge was the development of a connecting system which would permit both the rapid end-to-end connection of the structure and the accommodation of substantial loads. This has been achieved by the use of flanges and tie rods with a facility for angular and longitudinal adjustment.

What do you think of the proposal of the DVVD agency, and what were you expecting from this type of project?
The gauge of cladding used might have produced an overall structure of excessive solidity, but this is not the case. On the contrary, the structure is inviting to pedestrians, and protects the user from adverse external influences. This is certainly one of the finest pedestrian overpasses which I have had occasion to use.

How would you describe your collaboration with the DVVD agency in the execution of this project?
Notwithstanding the difficulties associated with any project, it should be noted that our collaboration with the DVVD agency has consistently been based upon confidence. This is a very significant point, as it has allowed the various parties involved to work dispassionately and to undertake constructive exchanges. In this regard, we would praise both the professionalism and the technical expertise of Clément Carrière, who has provided optimum support for the resolution of the various technical problems encountered.

DVVD Agency,

6 questions to Daniel Vaniche

What is special about DVVD?
Our work is based upon the idea of combining engineering and architecture, with no barrier between these disciplines. The agency also started out with a very particular project, an overbridge at Evry, which has since won numerous awards. In my opinion, the design of a civil engineering structure is an exercise in which there is no demarcation between design and engineering.

How does this parallel management of architectural design and engineering influence your work?
Firstly, I believe that the separation of functions represents a trap for the architect. Today, the architect is caught up in the division between architectural project management, technical project management and construction project management. In practice, the architect is increasingly involved in design, and less and less in construction. By incorporating not only engineering, but also works management into our business, we are able to manage projects more effectively, and to proceed more rapidly at the design stage.

Might there not be a risk that the engineer will guide the hand of the architect?
This is where discipline comes in. We always endeavour to push the boundaries of architecture further, for example by developing a number of projects in parallel during the schematic design phase. Engineering is sometimes a core element of the initial idea, but may also come later. We have no rules on this point.

Under these conditions, it is easier to manage project economics?
In our opinion, the management of project economics is a core element of design. We have two economists at the agency, who assist us as much as our engineers in the real-time validation of the various project options available. Many of our engineers also have the skills required for impeccable cost management.

Has the specific nature of the agency allowed you to secure particular projects?
We work, for example, on complex projects which involve the superimposition of different schemes. We also continue to work on civil engineering structures, and recently completed an overpass in Paris, over the Boulevard Périphérique. We also work on major reinstatement and redevelopment operations. The Bercy stadium is the most significant example. We are also working on designs for the transformation of the Salle Pleyel concert hall in Paris, and the Arènes theatre in Evry.

Presentation of 7 partners of the agency DVVD

DVVD is a Paris based group of architects, engineers, designers, builders and thinkers effective within the fields of architecture, urbanism, research and development. The office gathers over forty people, involved in a large number of projects throughout Europe. To deal with today and tomorrow challenges in urban design and architecture, we explore new fields by overlapping conventional approaches, taking advantage of our solid know-how, with new concept to better fit the future life forms. Finally, we create unique, lively, sustainable projects that reach beyond themselves
and become a durable value to the users, the society and the culture they are built into.

Vincent DOMINGUEZ Co-founder, he has contributed to the experience in engineering, architecture and design right from the earliest
days, not only regarding design itself but also in terms of expertise, methods and work-site techniques. His focus is on large scale public buildings in various cultural contexts. His overview and attention to detail strongly influence the office approach.

Daniel VANICHE Founder and CEO, Daniel Vaniche is a graduate of the Ecole Polytechnique
and Ecole Nationale des Ponts et Chaussées engineering schools, and architect. His experience both as an architect and an engineer convinced him that to bring these two skills together within a single structure made sense.

Bertrand POTEL Managing director since the first days and now partner, his design approach englobes a large identity-creating projects with a focus on designing strong, complete solutions based on complex design parameters. With a strong focus on the user aspect, design and organization of space, he has a special ability to maintain a strong concept throughout the project stages up to the construction.

Toma DRYJSKI Architect and urban designer, founder of the award winning archi5 practice, he recently joined DVVD as a partner. His international experience convinced him of the necessity to a constant overlapping of conventional approaches with free new concepts to fit with the future life of the projects. His experience covers developing of innovative sustainable concepts and building designs to complex masterplans and urban developments.

Louis RATAJCZAK Both engineer and architect, with his rich experience of complex projects he is naturally the referent of the engineers team. His department purpose is centered on structural innovation, for architecture and bridges, as well as complex envelopes design. He is also in charge to develop visions and solutions in the field of sustainable architecture and design.

Paula CASTRO Architect, she has successfully combined building design and technical matters with a particular attention to
envelopes and environmental aspects. She attaches a high priority to achieving the highest possible architectural quality and value for clients and users – based on a unique interaction between the brief requirements, technical solutions and other factors such as budget and time schedule.

Céline CERISIER Graduated in neuroscience and human resources, she has developed her skills in various service companies before joining the DVVD agency in 2006. She has supported the establishment and development of the administrative, financial and human resources pole for both agencies (DVVD and Daniel Vaniche & Associates). She constantly takes into account their respective evolution.