The Troche bridge is part of a broader initiative, the “plateau-valley connections”; which aims to provide soft (pedestrian and cyclist) links between the Yvette Valley—historical core of urbanization and transportation corridor (RER)—and the Saclay Plateau, a new internationally recognized university hub under construction.

These connections are spread across the Saclay campus territory, each adapted to specific geographical constraints and requiring varying degrees of intervention.

The Troche bridge connects Orsay Le Guichet East station to the Nano-Innov sector of the campus. The route includes, from the Le Guichet station exit, the Pont de Pierre street (120m), the Troche staircase (200m), and Vauve street (160m). At the end of this route, the path opens onto the Chanlon Park woods.
Its gives access to this largely unknown area largely, popular primarily among rock climbers rather than plateau residents.

The site has two main constraints: vegetation and topography. The project is situated in a wooded area that has grown from old overgrowth (since the 1950s) of a former sandstone quarry that previously occupied the entire plot. The quarrying had significantly impacted the natural environment. The current trees have developed on degraded soils. Thus, the woodland is relatively fragile, necessitating meticulous care in transporting materials and minimizing stress on existing vegetation.
The existing topography directly reflects the site’s former use, which left it extensively excavated. The most direct path through the woods consists of a generally flat surface over 100m, a slope of 21m in length and 4.4m in depth, and a 7.5m high, 30m long embankment.

On the campus of the Saclay Plateau, a thousands of engineers are trained. Every project, especially smaller ones, must showcase the engineering excellence of our time and meet the technical standards expected in our country.

The bridge project, developed in collaboration with engineering firm Bollinger + Grohmann result of a complex, time-intensive, and ambitious process.

The structure is inspired by an old rudimentary and modular bridge that existed in the same place. All its components—deck, posts, guardrails—appear to be of the same thickness. This formal simplicity, the starting point for the design of the bridge, is a technical challenge.

The structure’s continuity and subtlety instinctively guide users, drawing them along a path through dense woods, ever-present mud, and shadowed foliage. A guiding line—the guardrail—traverses the entire site, seamlessly integrating into the bridge.

The structure’s technical achievement lies in this subtlety: the woods themselves are the monument, while the experience of crossing becomes the focal point. At night, this continuity is enhanced by soft lighting embedded within the guardrail, illuminating the path and guiding line—just that, and nothing more.

Project Data

Landscape architure: Bassinet Turquin Paysage
Collaborators: Bollinger + Grohmann (structure), Alto-step
Location: France-PALAISEAU Carrière de la Troche (92)
Cost of the works: 500 k€
Year Built: 2020-2023
Area: 3000m2
Photo credits: ©Spectrum, ©Bassinet Turquin Paysage