Egis has been awarded a special mention by the International Federation of Concrete (FIB) in the "exceptional concrete structures" category for the Nouvelle Route du Littoral viaduct in La Réunion.
Last June, our Egis teams received, together with the Vinci group, the "special mention" in the "exceptional concrete structures 2022" category for their involvement in the "5,400 m viaduct" of the New Coastal Road. This prize gives international recognition to structures that demonstrate the versatility of concrete as a structural material. It is awarded every four years at the FIB Congress, which this year took place in Oslo.
A 5.4 km viaduct to make travel safer
The New Coastal Road, 12.4 km long, is one of the most complex in the world. Made up of viaducts and dykes, it will make travel between the two main economic centres of Reunion Island safer. Our teams have been working as complete project managers since 2011.
They have worked to make travel safer for users, whatever the weather conditions (except during the cyclone red alert period). The 5,400 m viaduct, delivered at the end of March 2021, has become the largest bridge over the sea in France.
- France's largest sea bridge adapted to heavy infrastructure
It has been designed to withstand, among other things, 100-year cyclonic swells and boat impacts and can support up to six lanes of traffic, including two lanes for tramway-type exclusive right-of-way public transport, for a period of 100 years.
The viaduct deck carries 2 x 3 lanes and is adaptable to the future development of public transport modes. This type of structure required complex finite element calculations to determine the right shapes and constructional arrangements.
- A design that ensures a reliable, proven and durable structure
In general, our design was oriented towards simplicity in order to facilitate prefabrication and industrialisation of the construction process. Our aim was to obtain reliable, proven and durable structures. The concrete formulas were specially developed for a 100-year life span in a very aggressive marine environment. In particular, the new performance approach to concrete was implemented.
The piers were designed to withstand ship impacts as well as 100-year cyclonic swells.
Three modelling approaches were used to estimate the hydrodynamic wave forces on the structure:
- Analytical tests,
- numerical tests
- and tests on physical 3D models.
The risk of a ship impacting the structure was assessed taking into account the current maritime traffic in the vicinity of the island, its likely evolution over time, the existence of a mooring area near the harbour, the frequency of observed damage and the possibilities of intervention by the harbour towing company.