The extension work being carried out on this section will connect the Nantes ring road to the A11 motorway. This axis connects Paris to Nantes and the extension work is expected to reduce journey times by 30%. It will also be able to absorb an increase in traffic of up to 25%, as well as reduce the impact of traffic by up to 40% on Boulevard Einstein.
Sarens, world leader in heavy lifting, engineered transport and crane rental services, has been directly involved in the installation of the new viaduct over the A11 at Porte des Gesvres, Nantes, on behalf of their client Bouygues Travaux Publics Régions France and owner VINCI Autoroutes. This new infrastructure, along with the viaduct connecting to the eastern ring road which was installed in January 2023, will allow for up to 25% increase in road traffic on the section, with a capacity of 115,000 vehicles per day, and reduce travel times by 30%.
To carry out the installation of this new bridge, which weighs 740 tons and has a curved metal structure of 110 meters long, Sarens Technical Solutions & Engineering, a specialist division of Sarens, deployed 4 Kamag SPMTs (Self-Propelled Modular Transports) of 6 axle lines. Additionally, they used 4 CS450 towers with 12 elements on one side, and 4 CS450 towers with 10 elements on the other side.
The Sarens technical team opted for the CS450 towers because of their versatility and large number of elements. By choosing these towers, their team could perform jacking down tasks as a faster pace, which was particularly important due to time constraints. The A11, a motorway currently used by over 90,000 vehicles per day, could only be closed for six hours overnight, reducing the time Sarens could use to travel the 70 meters using its SPMTs before jacking down the bridge.
Sarens Technical Solutions & Engineering faced several constraints that were finally overcome without any problems. Among them, the fact that the workspace was located on a motorway meant that only one truck could access the workspace at any given time, forcing the crew to follow a strict schedule for all the necessary transport movements.
Once all the elements were in place, Sarens used the CS450 towers to position the bridge structure on the SPMTs. To do this, they placed them on top of these transport elements, lifted the bridge structure by 5% across its width and transported them over 70 meters along the highway. Finally, the crew jacked it down two meters onto its final supports.
The infrastructure improvement project at Porte de Gesvres is considered crucial for improving traffic on the Nantes ring road. This particular section has only one lane of traffic, causing frequent traffic jams. The expansion of lanes from Porte de Rennes to Porte de la Chapelle will not only increase road capacity and reduce travel times , but will also facilitate rescue operations in case of any accidents. Additionally, it will reduce the impact of traffic by up to 40% on Boulevard Einstein, which is often used by drivers when the ring road is congested.
Over the past few years, Sarens has established itself as a strategic player in similar projects and in the international rail sector. Recently the company has completed several major projects, including the installation of the OA14 bridge, weighing 5,850 tons, in Bettembourg (Luxembourg). Sarens has installed a new pedestrian bridge between the Hazebrouck railway station (France) and its car park and an 8,400 ton railway bridge on the A1 motorway in Amsterdam (Netherlands). The company also replaced a railway bridge in Stockholm ‘s city centre of (Sweden) using the "floatover" method.
About Sarens
Sarens is the global leader and reference in crane rental, heavy lift and engineered transportation services. With state-of-the-art equipment, value engineering, one of the world's largest inventories of cranes, transporters and special rigging equipment, Sarens offers creative and intelligent solutions to today's heavy lifting and engineering transport challenges.
With more than 100 entities in 65 countries operating without borders, Sarens is an ideal partner for small to large-scale projects. Sarens currently employs 4,543 highly qualified professionals who are ready to serve the needs of any client worldwide and in all market sectors. https://www.sarens.com/