The construction and renovation of engineering structures are projects that require a wide range of skills. These projects provide an opportunity for the setec group to build on synergies between the different entities and draw on their complementary expertise.
Rehabilitation of the Rochers Noirs viaduct in Corrèze, France
Inaugurated in 1913, the Rochers Noirs viaduct spans the Luzège canyon in Corrèze at a height of 92 metres. Used by the Transcorrézien until 1959, it was closed to traffic in 2006, after the discovery of brittle elements when cold and significant corrosion of the cables. setec diadès and setec tpi are involved in the rehabilitation of this listed structure. A exceptional project!
The Rochers noirs viaduct is a rare Gisclard-type structure, rising up from a wild hillside. The Corrèze département, as the contracting authority, wanted to restore this emblematic monument of the Corrèze heritage to make it safer and reopen it to soft traffic.
setec tpi and setec diadès are combining their expertise as part of the design and technical management consortium headed by the architectural firm RL&A. The project involves replacing the existing suspension and anchors, replacing the decking, repairing the anti-corrosion system and historic railings, repairing the stonework on the piers and anchor chambers, and securing the boulders. setec tpi performs the conceptual and preliminary designs and the drafting of contract documents. setec diadès is involved in diagnosing the structure and monitoring the works. The works, which started in September 2022 and are due to be completed in September 2024, are being carried out under severe technical, environmental and heritage restrictions.
“As the bridge is listed as a Historic Monument, we were obliged to preserve as much of its original appearance and materials as possible, while ensuring that it could withstand the weight of a crowd and a service vehicle,” explains Etienne Combescure, setec tpi’s project director. The challenges also come from the natural environment.
“The site is difficult to access because it lies between two rocky slopes. Not all the machinery has access, and we had to use a helicopter to carry out some of the works”, reports Loriana Pace, diadès project engineer. Another major difficulty on this site was that the anchor cables were fixed into the cliff rock, so replacing the existing suspension and the cables that had reached the end of their lifespan meant installing a temporary suspension system before removing the old one.
“The site is full of technical challenges, the biggest of which is undoubtedly the cohabitation of the ‘classic’ temporary suspension design (with parabolic suspension cable and vertical hangers) and the installation of the Gisclard-type triangulated suspension,” confirms Mathieu Cardin, Director of the diadès agency in Bordeaux.
“This project is an opportunity for a rich collaboration between setec tpi, diadès and the Historical Monuments architect, who is providing valuable expertise. These lessons are interesting, as the renovation of engineering structures is an area in which setec is investing”, adds Etienne Combescure.