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Destination Findel: a new mobility challenge
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Destination Findel: a new mobility challenge
At Findel, our civil engineering teams are working on the construction of the new overpass on the A1. This project, designed to widen the N1, aims to optimise and improve the flow of traffic around the airport. This is essential in view of the growing volume of traffic that will be generated by the future Höhenhof transport hub, a true multimodal interchange that will connect trams, buses, park-and-ride facilities, cyclists and pedestrians.
Custom-made framework
This new road bridge, measuring 100 metres in length and 32 metres in width, is a complex structure combining reinforced concrete and steel framework. Its structure rests on:
- Two abutments anchoring the structure on either side of the motorway.
- Two load-bearing spans, each consisting of four 6-metre-high piers.
- Eight PRS-type steel girders, custom-made by our partner Cimolai, totalling 78.50 metres in length.
Each pier is designed to support two girders via two bearing pads – the anchoring bases – making a total of eight bearing pads per load-bearing axis. In total, 32 bearing pads and 32 jacking pads – installed for future maintenance – will be completed by July.
Spotlight on expertise: the challenge of formwork
The end of March saw the formwork removed from the final piers. Prior to this, our teams carried out precision carpentry work to construct bespoke wooden formwork, known as ‘mannequins’, which were inserted into the main mould.
They enabled the creation of very precise shapes in the concrete and gave the sides of the piers their distinctive geometry. This technical precision was enhanced by the use of polyurethane foam to ensure the formwork was watertight. Finally, protective casings were fitted over the metal protrusions on the bosses to prevent rust from seeping onto the fresh concrete of the piers during inclement weather.
A busy summer schedule
From May onwards, assembly of the steel framework will begin on site. The project will then proceed in three installation phases:
- Phase A from 10 to 13 July: Installation of 40-metre-long central beams weighing 90 tonnes. The A1 will be closed on both main carriageways from Friday at 10 pm until Monday at 4 am.
- Phase B from 24 to 25 August: Installation of 14.50-metre sections weighing 17 tonnes during the day.
- Phase C from 8 to 9 September: Installation of 24-metre sections weighing 27 tonnes above the motorway slip road.
Once the framework is in place, we will construct the cantilevered walkways – steel structures attached to the sides of the deck to create the cantilevered pavements over the void. The installation of these elements requires great technical precision and strict adherence to safety measures – a stage to be closely monitored!
Mobility reimagined
In the long term, traffic will be segregated to improve efficiency:
The existing bridge will be dedicated to traffic heading towards Senningerberg and will consist of two carriageways, a bus lane and a pavement. Meanwhile, the new structure will accommodate traffic heading towards Findel, featuring two carriageways, a bus lane and a shared footpath and cycle lane.
Congratulations to the teams on their precision work and for managing this logistical challenge.