Heavy lift specialist Sarens reports that it successfully maneuvered a 740-tonne bridge deck into place as part of A11 autoroute upgrade work near Nantes, France.
The 343km-long A 11 autoroute – also called L’Océane – connects Paris with Nantes via Le Mans and Angers. Sarens Technical Solutions and Engineering conducted the lift on behalf of customer Bouygues Travaux Publics Régions France and owner VINCI Autoroutes. The Sarens team successfully jacked up, transported and installed the 110m-long curved steel structure at the A11’s Portes de Gesvres interchange.
Equipment involved four Kamag SPMTs – self-propelled modular transporters – with six axle lines each. There were four CS450 towers with 12 elements on one side and another four CS450 towers with 10 elements on the other side.
The CS450, in particular, was chosen for its higher elements that allow the crew to jack down faster. This was especially important due to the project’s exacting time constraints. The A11 would be closed for only six hours during the night, giving the crew limited time to drive the SPMTs the 70m from where the bridge deck was constructed and successfully jack down the structure into place, over the four lanes of the A11.
Sarens notes that apart from the actual lift, there were other on-site challenges. First, because the job site was located along the highway, it meant there would be limited space and access for vehicles and equipment. For example, only one truck was allowed to enter the work site at a time. This meant that the crew had to meticulously follow a precise transport schedule.
Meanwhile, the road itself was a challenge. The crew would have to drive 70m across the A11 that was angled in two directions, with up to 4.5% in one direction requiring maximum SPMT stroke.
The necessary equipment arrived via 13 trucks from various locations around Europe. The crew assembled the SPMTs and their transport structure within one day, thanks to a well-coordinated pre-assembly effort at Sarens headquarters in Wolvertem, near Brussels in Belgium.
Next, it was time to jack-and-pack the 740-tonne curved bridge, jacking it from 1.5m to 4m high. From there, the CS450s took over. Positioned on top of the SPMTs, they lifted the bridge at an angle of 5% along its width for transporting it over 70m of highway. Finally, the crew jacked it down 2m onto its final supports – all within the brief six-hour timeframe.
Sarens noted that its team – especially the project team, engineers and eight on-site crew members – worked with usual precision and professional skill to make the installation a success.
