Video | Traffic avoids roadworks thanks to ‘mobile construction site’ bridge

The Astra Bridge, which is being assessed by Switzerland’s Federal Roads Office (Astra), has been in operation on the A1 road towards Zurich between Recherswil and the Luterbach junction for several weeks.

With an average of 73,000 vehicles running along the section per day, and 82,000 on peak days, the A1 is Switzerland’s busiest highway and Astra said that the route is prone to traffic jams and slowdowns. But it claimed that with the Astra bridge, billed as a mobile construction site, in place, “nothing has changed” in terms of traffic flow as compared to classic construction sites which divert traffic into the opposite lane and can cause significant disruptions.

So far, 1.3km of roadway has been resurfaced and work can be carried out even in the event of light rain. Every night, the Astra bridge, made up of  257m of steel decking, moves 100m further forwards. The useable space for workers underneath it is 100m.

Astra said, “The important data provided by traffic monitoring show that between the commissioning of the mobile construction bridge on 7 April 2024 and the reference day of 24 April 2024, constant traffic flows and stable traffic situations were recorded, apart from a few individual events due to the combination of snowfall, high traffic and accidents.”

The bridge, developed in partnership with industrial transporter company Cometto, first entered service in 2022 but traffic did not flow as desired during its pilot phase.

That led to the bridge being optimised in conjunction with Switzerland’s Federal Materials Testing and Research Laboratory as well as various road federations.

The ramps on the bridge were lengthened, reducing the slope of the access and exit ramps from a steeper gradient of 6.1%, down to just 1.25%. Vehicles, including semi-trailers, coaches, caravans and sports cars can all use the Astra bridge at a speed of up to 60 kmh (37mph).

The construction site bridge is intended for use during surfacing works, the replacement of road joints or the rehabilitation of bridges. Trucks with a low-loader trailer and large cranes are required for assembly and dismantling.