“For great evils, great remedies,” says the popular proverb, and that is precisely what the Swiss Federal Highway Office (FEDRO) has applied with the resurfacing works on the A-1 highway. In order not to be forced to cut off traffic on one of the most important communication routes in the country, those responsible for this body commissioned the construction of a mobile bridge that they move over the affected sections, thus ensuring the circulation of vehicles 24 hours a day. .
The resurfacing works on the A-1 are being carried out on a stretch of just over 1.5 kilometers between the towns of Recherswil and Luterbach, towards Zurich. Although it is a small space, this section has special relevance as it runs along one of the most important routes from north to south in the country. To do this, to avoid traffic chaos and guarantee traffic continuity, this ingenious solution has been implemented.
The mobile bridge has dimensions of 257 m long and 7.57 m wide. It is raised 4.65 m above the track and is mounted hydraulically, allowing both longitudinal and lateral movement. Once assembled and elevated, this mobile structure can move above the road as resurfacing work is carried out without affecting traffic.
In this way, oncoming traffic is not affected and the number and width of lanes, as well as the usual speed limits, are maintained. Furthermore, with this solution, the work area occupies a shorter section.
The bridge was raised in just two nights, between April 5 and 7, after having been improved after a previously failed pilot test on the same highway where it has now been installed. In a previous test on another section of the A-1, with cars and buses, other heavy vehicles were not taken into account. When the mobile bridge went into service, it was discovered that the 6.1% slope was too steep for trucks, making access difficult and causing traffic jams, precisely what the installation of this mobile structure wanted to avoid.
Now, the bridge that has been installed on the A-1 meets the requirements so that traffic is not affected during the works. The access ramp is longer to allow a smooth transition, while the slope has been reduced from 6.1% to 1.25%, making it easier for trucks to climb and avoiding the traffic jams that previously occurred.
At the same time, other improvements have been implemented after meticulous coordination with internal and external experts, including the Federal Materials and Research Laboratory and various traffic associations, thus ensuring that the bridge is suitable for all types of vehicles, from cars to trucks. of large tonnage. The machinery used in paving tasks was also taken into account, since some machines had problems with the height of the bridge.
The physical separation between the traffic area and the work area increases safety for both road users and personnel carrying out maintenance work. Workers also benefit from protection against traffic noise and inclement weather, as well as night work.
The latter is especially beneficial for nearby neighbors, since noise is significantly reduced during rest hours.
