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EXPLORING A WORLD ON THE MOVE P A G E 0 6 | L A FA R G E | O C T O B R E 2 0 0 7 | C R E S C E N D O © Jacques Rougerie architecte From lake dwellings, the city of Venice and oil platforms to Dubai’s artificial islands, man has always had both the desire and need to build on water. This architectural and technical challenge has today taken on a new significance with the increasing world population and climate change. Future Challenges of Marine Construction The Alexandria Museum of Underwater Archeology designed by Jacques Rougerie will be built underwater in the bay. l iving on, or even under water is not a new concept. The dream dates back to Greek mythology with Poseidon, the god of the sea, controlling the waves and stirring up storms with his trident. Closer to home, in Jules Verne’s famous “20,000 Leagues under the Sea”, Captain Nemo discovers the legendary lost continent of Atlantis. The leap between dream and reality is often a small one. Men were building villages on piles as far back as Neolithic times and there have been many examples over the centuries: the Mekong area in Asia, the “aquatic” districts of Benin in Africa, the amazing European city of Venice built on piles, and the construction of polders in the Netherlands. Not forgetting Tokyo and Monaco's extensions into the sea, and those in the Arab peninsula off the United Arab Emirates which are under construction. Today's ever-changing world is prompting more and more marine constructions to be built. Demographic change (the question of where to house the planet’s increasing population), climate change (the expected rise in water levels means that new building standards need to be introduced), and technological developments are all influencing factors. New materials now enable us to build structures that are more resistant to "the ravages of seawater". From myth to reality Although marine constructions seem to offer numerous opportunities at the moment, living on them raises a number of issues, not all of them technical. “The ocean remains synonymous with death and fear for many people,” points out Jacques Rougerie, an architect specializing in the marine environment. “But it continues to fascinate and the population C R E S C E N D O | L A FA R G E | N O V E M B E R 2 0 0 7 | P A G E 0 7
Tokyo, Japan, is extending its river banks. Tougher and cheaper materials mean that the town can extend onto the water. is migrating to the coast en masse. Maritime infrastructures are developing, such as off-shore platforms, airports (Nice, Seoul, Kobe, etc.), waterfront holiday villages like the Port-Grimaud water sports centre in Saint Tropez bay, and ‘underwater’ business and residential complexes being built in Dubai. We are expanding our living and working space into the sea and this is set to increase in the future." From hydro turbines to floating islands That is why marine environment projects are gaining momentum. “Financial obstacles are becoming less marked,” explains Jean-Philippe Zoppini, architect and chairman of the ‘Cités marines’ (ocean cities) association. “Costs are coming down all the time. They are still higher than for land construction, but for how much longer?” Construction in the marine environment offers solutions for man to take control of his future and environment. One example is the principality of Monaco. Faced with a serious lack of space, it invited international architects to come up with new solutions for extending into the sea to tackle population, land use and economic growth issues. Architects are now able to design fully independent floating cities. On the Ile d’AZ, Jean-Philippe Zoppini has even devised a system of mini trams P A G E 0 8 | L A FA R G E | N O V E M B E R 2 0 0 7 | C R E S C E N D O and conveyor belts to help residents to get around. Other projects involve harnessing water, wind, wave and solar power; water desalination systems; seafood production and satellite communication: a range of solutions providing the necessary services to marine developments. However, technological progress falls short in certain areas such as waste treatment, for example. According to Jacques Rougerie, “it is possible to treat waste, but only partially. Any constructions on water must be absolutely faultless in terms of waste as any risk of contaminating the oceans must be avoided at all costs," he concludes. By all means take the plunge, but be careful! Strength and durability of structures Most marine construction issues are of a technical nature, particularly in terms of the strength and durability of the materials (see boxed text). Concrete has undergone numerous changes since it was first used in the mid 19th century. Today's high-performance (HP) and very highperformance (VHP) concretes can produce high quality structures with a lifespan of up to 150 years. Marine constructions have to withstand two types of stress: mechanical stress (wind, waves, sea spray, tidal pressure, etc.) and chemical stress partly due to chloride weakening CONCRETE IS AT THE HEART OF TECHNICAL CHALLENGES “Right from when it was created in the mid 19th century, concrete has always served the same purpose: to make solid, reliable structures with an ever-increasing lifespan,” explains Richard Cavailles, team leader, products application and development at Lafarge. From the ‘rocky’ concrete of the 1850’s used for artistic structures, hydraulic, reinforced and pre-stressed concrete through to High-Performance and Very High- Performance concretes, the history of concrete in the marine environment has always faced a major challenge: how to withstand the effects of sea water and its environment. “We now have very high-quality concrete,” explains Richard Cavailles. “Our research and admixtures ensure that structures in or near to water have an excellent level of resistance, particularly to chloride, and a lifespan of over a century!" ■ © Getty Images EXPLORING A WORLD ON THE MOVE JACQUES ROUGERIE Marine architect. JEAN-PHILIPPE ZOPPINI Architect and president of the Cités Marines (Ocean Cities) association. the concrete and oxidizing its metal framework, and partly due to sulphate attack. For thirty years, clear progress has been made to slow down these phenomena by using highly compact concrete made with less water and adding admixtures to strengthen and increase the lifespan of structures. Cement quality standards have also been introduced, such as the French PM (pris de mer) standard. “Concrete’s exceptional qualities provide it with a long lifespan and low maintenance requirements,” confirms Jean-Philippe Zoppini. So, what about the future? According to Jean-Philippe Zoppini “it lies in floating systems that enable sites to be moved according to ocean conditions." One such system is the Ile d’AZ, his floating city concept designed in partnership with Alstom’s innovation department at its Saint Nazaire shipyard in France. This urban cruise liner would be home to nearly 10,000 people! Whether it is fantasy or reality the ocean obviously still stimulates our imagination! ■ C R E S C E N D O | L A FA R G E | N O V E M B E R 2 0 0 7 | P A G E 0 9 © ARR © REA
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