Sarens Excels in Time-Critical A11 Bridge Installation

Sarens Technical Solutions & Engineering recently completed a challenging bridge installation project on the A11 highway in Nantes, France. Working for Bouygues Travaux Publics Régions France and VINCI Autoroutes, the team successfully jacked, transported, and installed a 740-tonne, 110-meter long bridge at the Portes de Gesvres interchange in June 2023.

To meet the project’s time constraints, the team used 4 Kamag SPMTs with 6 axle lines each, along with 4 CS450 towers featuring 12 elements on one side and 10 elements on the other. The CS450 was chosen for its faster jacking capabilities. With only a 6-hour window for the A11 closure, precision and efficiency were crucial.

The project faced additional challenges due to limited space and access along the highway. Only one truck could enter the site at a time, requiring a meticulous transport schedule. The crew also navigated a curved highway with a 5% angle, presenting a maximum SPMT stroke of 4.5%.

Despite these challenges, Sarens’ expertise and equipment ensured success. Thirteen trucks from various European locations delivered the necessary equipment, which was assembled within a day at Sarens HQ in Wolvertem. The team then jacked the 740-tonne bridge from 1.5 meters to 4 meters high, using the CS450s on top of the SPMTs to transport it over 70 meters of highway. Finally, the crew lowered it two meters onto its final supports within the limited 6-hour timeframe.