Designing Sustainable Concrete: ETH Zurich’s HiLo Unit
Dübendorf, Switzerland, is the holy ground for architects and architectural technologists. On the shared academic campus of the Swiss Federal Laboratories for Materials Science and Technology and the Swiss Federal Institute of Aquatic Science and Technology, public university ETH Zurich has conducted nearly a decade of engineering and construction research at the ever-changing NEST research building. In August, ETH Zürich unveiled HiLo (short for high performance, low emissions), two-story modular addition to the chameleon structure that combines mediaeval building principles with contemporary digital methods to raise the bar for more sustainable concrete applications.
The project was designed by ROK Architekten of Zurich in collaboration with the Block Research Group at ETH Zürich and the Architecture and Building Systems research group at ETH Zürich. Because ancient master builders lacked access to materials such as reinforced concrete, they were forced to limit their designs to those that could be constructed using the more modest materials available at the time. This resulted in the use of well-known structural typologies from that era, such as domes and arches, “notes Dr Tom Van Mele, senior scientist at the Block Research Group. With the HiLo floors, we reintroduce these curved geometries to more efficiently span space, using significantly less material and lower-strength materials, all while keeping the materials separated for easy recycling at the end of life. Furthermore, in comparison to more traditional floor plate solutions, digital fabrication technologies enable the fabrication and construction of these curved geometries.
Construction began in September 2019 with the completion of the formwork system, though the concrete pour was delayed until fall 2020 due to colder than expected temperatures that winter. Medieval construction techniques are manifested mainly in the geometry of the structure. The roof was formed using a flexible formwork system that utilises a tensioned cable net embedded within the boundary frame as the primary load-bearing element and a tensioned membrane as a shuttering layer. The same cable net is stiffened via a doubly curved geometry that deforms into its final shape when the wet concrete is sprayed.
All of the roof structure’s critical details, including its formwork system, were worked out through prototyping in collaboration with industry experts and partners. The developed solutions were integrated into a flexible design-to-fabrication workflow using COMPAS, an open-source computational framework for research and collaboration in architecture engineering and construction, according to a press release from ETH Zürich. “This workflow served as a focal point for the computational development, coordination, and planning of the key innovations, and served as an efficient mechanism for transferring research to practice.”
The sustainability and efficiency of the project extend beyond the roof structure. At the floorplate, the team developed a rib-strengthened funicular system for transferring loads to the structure’s corners, eliminating approximately 70% of the concrete and 90% of the reinforcement steel typically used in a reinforced concrete floor slab. Additionally, the narrower slab width enabled the integration of heating and cooling pipes, resulting in a highly efficient radiant panel thermal system. Additionally, the team included 30 adjustable photovoltaic modules on the facade, which can be adjusted to maximise solar energy or control how sunlight enters the module.
While HiLo is the eighth module of NEST, the research building will continue to evolve as a testing ground for building scientists, engineers, and industry partners in the years to come. We’ll have to wait and see what the researchers at ETH Zürich come up with next.
Written By Tannu Sharma | Subscribe To Our Telegram Channel To Get Latest Updates And Don’t Forget To Follow Our Social Media Handles Facebook | Instagram | LinkedIn | Twitter. To Get the Latest Updates From Arco Unico