The Seonyu footbridge, the world's first structure constructed in Ductal®, an Ultra High-strength Fiber Reinforced Concrete, has been inaugurated at a ceremony organised by the City of Seoul in South Korea. This footbridge, linking the South Korean capital to the island of Seonyu, was built by VSL-Intrafor, a Bouygues Construction subsidiary specialising in foundations and prestressed concrete, using Ductal®, supplied by Lafarge. The very innovative concrete, Ductal®, was recently developed jointly by research teams of Bouygues Construction, Lafarge and Rhodia.
This Ductal® footbridge is one of the world's unique architectural feats. It consists of an arch which spans 120 metres (made up of six voussoirs 20 metres long and 1.30 metres deep) and supports a deck only 3 cm thick. It therefore has extremely sleek proportions which could not have been achieved with traditional concrete. A structure in Ductal® requires only half the amount of material by comparison with traditional concrete to provide equivalent load-bearing and strength properties.
Ductal® possesses exceptional properties. Besides having high compressive and flexural strength, it is a ductile material. Ductility, which is a property it shares with no other type of concrete, gives it its name. In addition to its capacity to withstand substantial stress, it is resistant to abrasion, the ravages of pollution and bad weather and to scratching, on a par with granite. Its durability characteristics, guaranteeing less maintenance need, is a cost reducing effect throughout the lifespan of the structure. It is perfectly adaptable to differently textured and shaped moulds. The very fine matrix, which can be as smooth as marble top, allows architects to create different textures and reveal lightness.
The arch-shaped structure was designed by architect Rudy Ricciotti and is part of a project to transform the Seonyu island into an urban park. Jointly conceived by the City of Seoul and "France's Year 2000 Committee" to commemorate the new Millennium, the footbridge symbolises the co-operation and friendship between South Korea and France.
A modern material par excellence, Ductal® opens up new horizons for architects and engineers. The choice of Ductal® for this South Korean project underlines the strong presence of Bouygues Construction and Lafarge in Asia, just a few weeks before the Soccer World Cup.
For Bouygues Construction, Asia represents an important development area. The company is active through its subsidiaries Dragages Asia, BYME (engineering) and VSL-Intrafor (foundations and prestressed concrete). In 2001, Bouygues Construction generated revenues of almost 800 million euros in Asia/Pacific. Bouygues Construction, an expanding firm with strong entrepreneurial values, is a world leader (annual sales of € 6.3 billion and 40 000 employees). A subsidiary of the Bouygues group, it operates in 70 countries worldwide. Active in four business areas (building, civil works, energy services, electricity/networks) Bouygues Construction is enhancing its full-service offering with an extensive range of services and skills all along the value chain.
Lafarge is present in South Korea through its affiliate Lafarge Halla Cement Corporation. Its cement plant in Okke has an annual production capacity of 7,4 MT. Lafarge is also present via its joint-venture "Tong Yang Cement Corporation Ltd, Co.", which owns a cement plant in Samchok. The latter has an annual production capacity of 11 MT. Lafarge is also the leader in gypsum wallboard in South Korea, with plants in Yosu and Ulsan.
Lafarge is the world leader in building materials, and employs 83,000 people in 75 countries. The Group holds top-ranking positions in all four of its Divisions: Cement, Aggregates & Concrete, Roofing and Gypsum. Lafarge posted sales of €13.7 billion in 2001.