Press Kit Overpass on the Loing

DVVD Overpass on the Loing Press kit

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Overpass on the Loing Self-apparent elegance

Designed by the DVVD architecture, design and engineering agency, the overpass on the Loing links the municipalities of Saint-Mammès and Veneux-les-Sablons, in the department of Seine-et-Marne. More than just a connecting structure, this is a sculptural work which banks upon simplicity and elegance in design to enhance an equally remarkable site.

At the confluence of the Loing and the Seine, the overpass constructed by the DVVD architecture, design and engineering agency blends perfectly with its remarkable setting in the heart of Seine-et-Marne, a favourite site for walkers in the Ile-de-France. This panorama inspired numerous studies, sketches and paintings by the famous impressionist artist Alfred Sisley in the late 19th century. !00 years later, the spirit of creativity is still at large here, as evinced by the cleancut metal arch, 67 metres in length, which connects the municipalities of Saint-Mammès and Veneux-lesSablons. First conceived early in the 20th century, the installation of an overpass has been much discussed

since, with a fear in many quarters of the consequent spoiling of the site.

It was by the particular consideration of this mandatory respect for the existing setting that the DVVD agency was able to win the competition organized in 2010 by the Inter-municipal Syndicate of Boundary Developers [Syndicat Intercommunal des Maisons du Bornage]. Given a free choice of location, the architects sited their project at the margins of the Seine, at a location where the Loing is relatively broad, and where the banks are free of road traffic and urban development.

This siting also allows the lines of force delivered by the landscape to be exploited, and to enjoy the fruits of reciprocal enhancement.

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More than just an overpass, a panoramic viewpoint over the river

Caressing both banks, the overpass unfurls freely, on the left bank towards the Veneux-les-Sablons tow path, and on the right bank towards the car park of the Saint-Mammès market. Its arched form is more clearly suggestive of a water crossing than a girder or trellis structure, while establishing a strong visual link between the two towns.

The structure is supported on foundations which are independent of the banks, which themselves are reinforced over a length of 10 – 15 metres: on the Saint-Mammès side, the existing quayside, of cement construction but affected by cracks, has been consolidated by the installation of a beam; on the Veneux-les-Sablons side, a bundled structure of willows and timber piles, combined with geotextiles, improves the mechanical strength of the bank, hitherto comprised of backfill covered with herbaceous vegetation and a few woody plants. The symmetrical design of this structure is comprised of two slender load-bearing arches, with a deck suspended from reinforcements which are supported by the arches. Manufactured and painted at the Viry workshops in Remiremont (Vosges), the latter were transported in three sections respectively and welded in situ.

The curvature in elevation is matched by the curvature of the decking plane: the decking is expanded in the central section to form a panoramic viewpoint over the river. Over and above its function as a crossing, the overpass serves as a landmark, a destination for walkers and an exceptional observation point.

This is the landscape of the Impressionists. While the details of the steel structure and the oak walkway emphasize the contemporary nature of this facility, the arched design of the overpass is entirely in keeping with this vernacular — Bertrand Potel

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Engineering in the service of integration

elevation view

The overpass is distinguished by the restraint and elegance of its geometry, which render it virtually transparent in the landscape, without impairing the impression of freedom and exposure to the sky which are symbolic of the confluence of the Loing and the Seine. This sensation is attributable to the lightweight profile of its superstructure, constructed of highperformance steel, for the optimization of structural behaviour. The arches are designed in rectangular sections, reconstituted by welding, constant in the area above the decking and of variable inertia in the lower sections, flaring to form a bedding structure at ground level. The reinforcements which support the decking are also reconstituted by welding in a variable inertia arrangement, and are suspended from the arches. The overall form of the structure is resistant to

bending, but also to torsional loading associated with winds or the application of imbalanced dynamic loads to the decking. Dictated by the proximity of the naval shipyard, the air draft has been extended up to 6 metres, reducing the visual impact of the structure while enhancing the dynamism of its design. Broadly-spaced cradles (at intervals of 5.40 metres) are suspended below the arches, and carry H-section girders for the formation of the decking structure. In the interests of convenience, natural water drainage and anti-slip properties, the latter is formed of rot-proof timber planks in a crosswise arrangement. The architects from DVVD summarize the design as follows : “ In spirit, the project as a whole is distinguished by details, which we have endeavoured to keep clean and simple, allowing the intent of the project to take precedence ”.

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Ease of use and maintenance

We have conceived and designed this overpass as an indissociable element of a whole – the towns concerned and their urban development – in consideration of its multi-faceted aspects. Its qualities should make it an obvious feature, as though it had always been part of the landscape of the confluence — Daniel Vaniche

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Constraints associated with the observation of the river transport loading gauge, and associated with accessibility for environment-friendly forms of transport and persons with reduced mobility, have resulted in the deployment of appropriate systems. In order to avoid blocking the view to the river, and to prevent the loss of parking spaces, the option of ramps has been excluded. The least cumbersome access solutions possible have been preferred: two stairways, in compliance with PRM standards, supplemented by two smooth and inclined platforms for the upward access of pushchairs, and a rail to facilitate the climbing and descent of bikes. In preference to the deployment of lifts, and their resulting encumbrance on the landscape, monolifts are arranged along the discrete safety rails on each

bank, with reinforcements for the installation of two guide rails. The stairways are provided with a similar finish to the decking, with 195 x 35 planks at 40-millimetre intervals, of sufficient width to be secured at four to six points, and longitudinally grooved. The anti-slip facility is enhanced by the incorporation in each plank of two machined recesses, filled with a mixture of silica sand and resin of the corundum type. In the interests of safety and comfort during crossing, the decking is lit from the safety rails, with the addition of projectors to illuminate the arches from the base of the structure. All hardware has been selected with characteristics which will permit operation in a punishing urban environment, with limited maintenance requirements.

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An exemplary project

Given the importance of this structure, and its location, highly stringent regulatory conditions have been applied. An initial detailed analysis of hydraulic impacts (with the modelling of water run-off at the confluence, under normal circumstances but also under high-water conditions), revealed a very low, if not zero impact upon water run-off, associated with the limited footprint and the slender design of this structure. An evaluation of impacts upon the natural environment was also completed and referred to the River Police who, after the conduct of an analysis, approved the execution of the project. As this is a classified site, a number of meetings with the architectural heritage agency ABF (“Architectes des Bâtiments de Franceâ€?) and with the DRIEE (Regional and Inter-departmental Directorate for the Environment and Energy) were also necessary for the optimum appraisal of impact upon the landscape, and for the finalization of the moss grey colour of the metal components.

In complete harmony with the landscape, the DVVD agency has delivered a work which is remarkable in every respect: elegant lines, lightweight construction, simplicity, accessibility and low impact. With these qualities, the overpass creates a sense of always having belonged to its surroundings. This project convinces by the strength of evidence.

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5 Questions to Yves Brument, Mayor of the municipality of Saint-Mammès

What were your initial impressions of the installation of the overpass on the Loing ?

A huge achievement ! This is an impressive civil engineering structure, combining finesse with aesthetic appeal, which exudes robustness, notwithstanding a degree of elasticity (there is some perceptible movement in the wind …)

How can you and would you define this overpass ?

This is a territorial linking structure, which not only connects the river banks, but also the residents of the southern area of Seine-et-Marne.

What expected and unexpected repercussions have been experienced by the municipality of Saint-Mammès since the commissioning of the overpass ?

As we would have anticipated, this facility has been popular with users since its opening. There has been some curiosity, but this structure is a genuine tool for local development, and particularly for tourism.

What do you think of the proposal of the DVVD agency, and what were you expecting from this type of project ?

The proposal of the DVVD agency caught our attention by the lightweight design of the structure.

What feedback have you received from residents ?

Highly positive in 95% of cases.

Detractors are in the minority, but have the loudest voices. Anticipated for years, this overpass will contribute to the enhancement of views of the confluence, and is already part of our heritage.

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5 Questions to François Dewilde, Project manager from the contractor Segex What were the major stages in the construction process ?

These major stages can be summarized as follows : Construction of deep foundations Construction of supporting abutments for the overpass Construction of the metal overpass in the workshop On-site assembly of the overpass Installation of the overpass Installation of timber decking and ancillary equipment (lifts, lighting, etc.)

How can you and would you define this overpass ?

As constructors, it is difficult for us to give a definition of this overpass, but it has been conceived in consideration of its geographical location (close to Morêt-sur-Loing), the facility to be spanned, and the loading gauge below the decking to be observed. Its arched structure, of the bowstring bridge type, confers an exceptionally lightweight and slender quality.

What were the technical challenges involved for your company ?

The contractor SEGEX, as agents for the SEGEX/VIRY/DVVD construction consortium, has been responsible for the construction of the foundations of the structure and the supporting abutments. One of the key technical challenges was the production of the supporting abutments of the overpass to a construction tolerance of 1 centimetre in three dimensions, over a span of 68 metres. Our ingenious solution involved the construction of a temporary gantry structure which allowed the adjustment of the seating plates embedded in the concrete structure, under the supervision of a surveyor, to the stipulated tolerance margin.

What do you think of the proposal of the DVVD agency, and what were you expecting from this type of project ?

As this was a design and construction project, we were involved at a very early stage, ahead of the design of the structure, and there were no surprises involved. The proposal of the DVVD agency perfectly matches the specification, whilst integrating very successfully with the surroundings.

How would you describe your collaboration with the DVVD agency in the execution of this project ?

The SEGEX Group has undertaken numerous projects with the DVVD agency, and we know each other well.

Our collaboration is based upon respect, responsiveness, and the consideration of requests for modifications and adjustments dictated by the project.

We have also observed the reciprocal fulfilment of these criteria by the DVVD agency. In this project, collaboration proceeded under very good conditions, resulting in the delivery of a particularly satisfactory overpass.

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design work. Another challenge was the erection of the fully-assembled

5 Questions to Marie Colné, Project manager, from the contractor Viry first sketches

overpass, which involved the use of a 600-tonne trellis tower crane, running on caterpillar tracks. The transport of this crane and its counterweights alone required some twenty semi-trailers.

This spectacular erection operation was watched by many local residents.

What do you think of the proposal of the DVVD agency, and what were you expecting from this type of project ?

What were the major stages in the construction process ?

Eight stages can be identified : Once construction plans have been validated, we can proceed with the establishment of production plans: component production plans and assembly plans, of the type produced by a project sponsor Cutting of sheet metal on an oxy-fuel cutting or laser cutting station Assembly of sheet metal in assembly jigs for the constitution of components.

The arches of the overpass, for example, were assembled in full in our workshops, using a complete workshop hall (nearly 70 metres in length)

Components were then welded together to form subassemblies, transportable by exceptional convoys The complete deck, which is curved and of variable width, was dry assembled in order to ensure the correct fitting of all the components, and in the interests of accuracy during on-site erection Geometrical quality controls, and the execution of various controls on welds Delivery to a specialized workshop for painting (the Chiarizia workshop, near Nancy) On-site delivery of components, overall assembly of the structure on stays, welding, execution of controls and erection of the complete overpass.

How can you and would you define this overpass ?

The architectural proposal of the DVVD agency was well-matched to the technical solution applied for its delivery – this is typically one of the appreciable characteristics of DVVD agency projects.

A fine structure, combining the lightness and finesse of architectural design with the technical expertise required to bridge a major span of 67.3 metres.

How would you describe your collaboration with the DVVD agency in the execution of this project ?

What were the technical challenges involved for your company ?

The major challenge was to accommodate this substantial span whilst maintaining a slender and lightweight structure, in accordance with the design delivered by the DVVD agency. The apparent simplicity of the outcome is the result of detailed

This design and construction project was the subject of a major pre-project development phase, in order to allow the development of this facility on a very restricted budget. An ongoing dialogue between architects and contractors allowed the optimization of this structure and its construction.

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Technical data sheet Location : Moret-sur-Loing (Seine-et-Marne) Contracting authority : I nter-municipal Syndicate of Boundary Developers Architecture, engineering, design : DVVD : DVVD : Paula Castro, Céline Cerisier, Vincent Dominguez, Toma Dryjski, Bertrand Potel, Louis Ratajczak, Daniel Vaniche. Project manager : Carlota Guillen Contractors : Segex (gros-œuvre), Viry (charpente métallique) Budget : 2 600 000 euros ex. tax Span : 76 metres Lenght : 67 metres Width : 5 metres Competition : 2010 Construction : 2014-2015 Delivery : june 2015

Credits : Sketches, boards and 3D: DVVD Photography : D.Rousselot and DVVD Illustration and photos are free of rights

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DVVD 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.

As an engineer, do you work for other architects ?

While we have our own signature projects, we continue to work for other agencies. This allows us to interact with other professionals, but also to explore new materials and alternative options.

We choose not to limit ourselves.

By working with Jean Nouvel, MVRDV, Wilmotte & Partners, or with Vincent Parreira and Stéphane Maupin, we remain open to different forms of contemporary architecture. Together with Anthony Béchu and Tom Sheehan, for example, we recently realized the first steel-framed skyscraper to be built in France for decades. The D2 Tower in La Défense therefore represents the work of a number of agencies. In any event, this structure reflects the importance of the engineer’s work.

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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.

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Daniel Vaniche

Toma Dryjski

Paula Castro

Founder and CEO, Daniel Vaniche is a graduate of the Ecole Polytechnique and Ecole Nationale des Ponts et ChaussĂŠes 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.

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.

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.

Vincent Dominguez

Bertrand Potel

Louis Ratajczak

CĂŠline Cerisier

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.

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.

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.

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.

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Awards

Footbridge ZAC Claude Bernard Nominated for the Equerre d’Argent 2015 prize

The Leaf Double winner (Jury and Popular Choice) of the 2013 A+Awards, Architecture+Mobility category Winner of the Construction and Innovation Batiactu 2013 Trophy Winner of the Salon d’Automne Architecture 2012 Prize

Footbridge over the river Marne Winner of the Construction and Innovation Batiactu 2011 Trophy

The Propeller Winner of the Paris Metropolis General Public 2005-2010 Award for Contemporary Architecture, Public Spaces category Winner of the Luxembourg Steel Construction 2007 Prize Nominated for the Equerre d’Argent 2007 prize

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