Low-cost apartments incorporating smart materials

Depending on the orientation of the elements, the system can generate an astonishing array of variable ground plans. Since the walls only take vertical loads (horizontal loads are taken up by the central core), the system accommodates a high flexibility in the spatial organization of the ground plans. The concrete walls themselves are 50cm thick. The concrete is mixed with an aggregate of recycled glass, which reduces its density to less than 800 kilograms per cubic meter. The weight of the concrete is further reduced by using glass fiber for reinforcement instead of steel. Snake-like tubes inserted in the outer portion of the concrete serve as solar collectors. Thanks to these measures, the concrete is thermally self-insulating, and does not require insulating materials to be applied to the exterior – its bare-faced concrete again, like in the heyday of modernism, but this time environmentally sound.

The outstanding merits of this innovative concrete production method are fourfold: First, it eliminates the need to use expensive and marginally-recyclable construction materials such as wood and steel sheet, while replacing the traditional materials for concrete formwork by wax. At the same time, it reduces formwork-related construction waste almost to zero. Second, it considerably cuts down the tremendous volume of manual labor necessary to produce highly complex concrete formwork because robots take-over the majority of the workload. Third, the relatively low cost of this formwork technology is a prerequisite for the economical production of geometrically complex precast concrete elements in small series. Fourth, there are virtually no limits regarding the three-dimensional shape of precast concrete elements with a hitherto unimaginable degree of accuracy.

Overall, this visionary formwork technology for geometrically complex concrete elements is a real quantum leap combining the utmost computer-aided manufacture (CAM) technologies with the latest generation of robots that has the potential for revolutionizing the construction process enhancing sustainable construction.

The Holcim Innovation prize honors projects that represent the leading edge of materials innovation and new approaches to building technology. Frank Barkow and Regine Leibinger of Barkow Leibinger Architects in Berlin, along with Mike Schlaich, Technical University of Berlin (TU Berlin), and Matthias Schuler, Transsolar Energietechnik in Stuttgart designed a Smart Material House that addresses the provision of low-cost housing in the City of Hamburg – that meets the needs for economic and ecological performance, as well as architectural aesthetics and social equity.

Adroit design techniques are combined with smart materials including infra-lightweight concrete and glued laminated timber (glulam) are stacked like a “house of cards” to create multi-level apartments of 90-225 m2. The pre-fabricated concrete used weighs only one third of conventional concrete: yet it delivers additional benefits to the building. The massive curved, precast elements are load-bearing walls, delineate space, provide thermal insulation, and also encase parts of the heating and cooling system.

Chairman of the Global Holcim Innovation prize jury, renowned architect and Professor at the Swiss Federal Institute of Technology (EPFL) in Lausanne, Harry Gugger, considers the technology to be a quantum leap. “The project team has developed a simple, monolithic structure, while pursuing a formally ambitious concept for low-cost housing, that has created an aesthetically-pleasing environment with an architectural quality in terms of space, form, light, and ambiance,” he said.

The prize of USD 50,000 was presented at the IBA Hamburg by Werner Sobek. The eminent civil engineer and Director of the Institute for Lightweight Structures and Conceptual Design (ILEK) at the University of Stuttgart, was also a member of the Global Holcim Awards jury. Guests were welcomed by Uli Hellweg, CEO of IBA Hamburg.

Roland Köhler, Member of the Executive Committee of Holcim responsible for Europe, and Leo Mittelholzer, CEO of Holcim Germany focused their speeches on the commitment of Holcim in the area of sustainability. “As a producer of construction materials we are at the beginning of a value creation chain. Our intention is to build awareness of sustainable construction amongst professionals and the public and to strengthen its significance in research and development, and in practice,” said Leo Mittelholzer.

Prizes for sustainable construction solutions

The presentation of the first Innovation prizes is a highlight of the 3rd Holcim Awards competition. The competition seeks innovative, future-oriented and tangible construction projects to promote sustainable responses to the technological, environmental, socioeconomic and cultural issues affecting building and construction on a local, regional and global level.

The competition takes place first across five global regions, with prize-winners progressing to a global phase. All 53 projects that were awarded a prize in the regional phase of the competition in 2011 were eligible to compete for global Holcim Innovation prizes. Further Holcim Innovation prizes were presented to the High-efficiency concrete formwork technology project by Fabio Gramazio and Matthias Kohler, Professors of Architecture and Digital Fabrication at the Swiss Federal Institute of Technology (ETH Zurich), and to a group of students of the AA School of Architecture in London, for their Cast on cast: efficient fabrication system for geometrically complex building elements.

The units range in size between 90-225sq m and incorporate fast-growth fir decking slabs with pre-fabricated infra-lightweight concrete walls.

The lightweight concrete is one-third of the weight of conventional concrete, is self-insulated utilizing recycled foamed glass as an internal aggregate and allows the building to approach a zero-carbon material effect. The walls are embedded with tube conduits to provide conductive heating and cooling via water, triple-glazing improves sound and heat insulation, and the roof is planted with local vegetation.