As part of the reconstruction of the cable car stations in the Les Grands Montets ski area in the Chamonix Valley, France, a significant milestone has been reached: the prototype of the modular load-bearing structure that will form the basis of the future buildings has been successfully assembled and thoroughly tested.
The project involves the rebuilding of the cable car infrastructure destroyed by fire in 2018. Three new stations are being constructed at Argentière (1,275 m), Lognan (1,950 m), and the Grands Montets Pass (3,200 m). The architectural design is by RPBW Renzo Piano Building Workshop and draws inspiration from the crystal structure of pyrite, a natural mineral found in the Mont Blanc massif. The buildings appear as clearly defined cubes integrated into the alpine surroundings, made of modular steel structures combined with concrete volumes that house all operational functions.
To validate the structural concept, a full-scale prototype consisting of four prefabricated modules was assembled. Each module is connected by 4 struts and braced by 8 tie rods assembled by a central casting, known as corpo centrale. This cast steel element is identical across all modules and weighs approximately 22 kilograms. The components are connected using a custom-developed clavetage system, which allows for rapid and precise assembly while ensuring high structural performance.
The test series includes load tests conducted under near-real conditions. The aim is to verify the structural capacity of the prestressed modular system and evaluate its behavior under serviceability actions, amongst which wide temperature fluctuations, important snow loads, strong winds. In addition, the full-scale prototype was carried out to assess the mechanical performance and reliability of our innovative assembly system in terms of ease of assembly, efficiency, and reversibility.
Initial results confirm both the load-bearing capacity and the assembly suitability of the modular system, validating the technical choices made in conception, and marking a key step toward fabrication and construction. In parallel, impact tests were carried out on the structural silicone glazing of the facades as part of an approval in individual cases (ATEX) process.
The next phase of testing will focus on low-temperature conditions, with the objective of assessing the risk of brittle fracture in both the cast and machined components developed for the project.
At the Aiguille site (3,235 m), a total of 114 modules will be assembled into a cube-shaped structure measuring 20 × 20 × 20 meters, embedded directly into the rock face. The design includes a suspended viewing platform beneath a timber roof. At the Lognan site (1,950 m), a transparent crystal-like volume measuring 20 × 20 × 17.5 meters will be formed from 135 modules and integrated into the existing TOPO infrastructure. The facades will feature bi- and tri-laminated glazing with a particularly low iron content. The extra-clear glass is treated with a special bird-protection coating to prevent collisions and ensure ecological compatibility.
