White Tower  (Tor Alva), Mulegns   (work in progress)

with Benjamin Dillenburger / DBT ETHZ

Tor Alva (“White Tower”) is a 30-meter tall, 3D-printed building situated along the Julier mountain pass in the remote village of Mulegns, Switzerland. Designed for Fundaziun Origen, the tower functions as a beacon in the village and offers space for art installations and for music and theater performances. With its spectacular architecture and ground-breaking technology, the tower demonstrates the possibilities that computational design and digital fabrication offer the fields of architecture and construction. These include not only economic and ecological advantages, but they allow for an elaborate non-standard architecture with a bold wealth of shapes.
 

Architecture, Art and Cul­ture

The white tower serves as a walk-in installation, an intimate concert venue, and as place of cultural mediation. The central design element of Tor Alva consists of 32 branching columns that enclose a sequence of abstract, atmospheric rooms. Visitors ascend through this vertical enfilade to reach the vaulted concert venue on the top floor. This intimate hall can host an audience of 45 visitors, and it offers panoramic views across the Julier Valley. The tower’s striking variety of shapes is reminiscent of the craftsmanship of the master builders of the Baroque era in Grisons.
 

Research and Innovation

Tor Alva demonstrates the ground-breaking possibilities of research in computational design, digital fabrication, structural engineering and materials science. The innovations in these research fields will fundamentally change construction and make it more sustainable. Using robotic concrete extrusion processes, concrete can only be applied where it is structurally needed, thereby significantly reducing material consumption. The process no longer requires any formwork. This in turn offers new degrees of design freedom regarding expressive shapes, surface detailing, and hollow features. It also allows for the production of one-of-a-kind, non-standard architectural elements. Investigating concepts of circularity and reuse, the tower will be constructed with disassembly in mind so that it can be rebuilt at another location after its five-year life in Mulegns.

Architecture, Art, and Cul­ture

The White Tower of Mulegns will be built directly on top of the historic carriage depot. The building is designed as a vertical enfilade consisting of six floors. These abstract, atmospherically dense spaces range from dark and enclosed rooms at the bottom to light and airy ones on top. Each floor has its individual system of ornament and enables strong spatial experiences. Their unique formal expressions are held together by the unity of the material. In winter, the tower will be protected from wind and snow with a removable membrane. At dusk, the White Tower with its idiosyncratic openings appears like a lantern and becomes a lighthouse along the old Julier Pass route.
 

Performance Space

Tor Alva's high and bright theater hall offers panoramic views over the impressive alpine landscape and the village of Mulegns. This hall offers space for 45 visitors, who can follow small events under the tower dome: concerts with Rhaeto-Romanic songs, electronic compositions, author readings and contemporary choreographies. The roof structure consists of a central, vaulted roof and eight delicate dome supports.
 

Columns as the Central Element

The central design element of the tower consists of a series of 32 branching columns, manufactured using the 3D printing process, which support the different levels of the building and form its facade. In the lower zones, heavy, squat columns create narrow, imposing spaces. As you climb the central spiral staircase, the room becomes noticeably lighter and airier. Each column is decorated twice: with a horizontal materially-driven ornament derived from the concrete printing process and an overlying spiral texture that emphasizes the height of the building. The light-colored materials and striking structures enhance the architectural play of light and shadow.

Fabrication: 3D Concrete Print­ing

The construction of the future faces major challenges: humanity worldwide is confronted with a growing need for buildings as a result of urbanization. This makes it increasingly relevant to build sustainably and cost-effectively. The answers to this can only be found together with a radical digitalization of architecture and the construction industry. Robotic additive manufacturing techniques such as 3D printing are of great importance in this regard. At 30m high including the base, the White Tower will be the tallest 3D-printed building in the world.
 

3D-Printed, Reinforced Concrete

Tor Alva is made from concrete using a 3D printing process developed at the DBT Group of ETH Zurich. In this innovative manufacturing process, a robot successively applies thin layers of soft concrete through a nozzle. The material is soft enough to bond and form homogeneous components, but hardens quickly enough to support the successive layers. In the White Tower, the printed concrete is used fully structurally for the first time and the necessary steel reinforcement is inserted in the robotic manufacturing process - a significant milestone in the development of 3D printing of concrete.
 

Efficient Use of Material

In the tower's thin-walled, hollow columns, concrete is used only where it is structurally required; similar to optimized structures that we know from nature. Saving mass and cement means a reduction in the CO² emissions generated during its production.
 

Formwork-free Construction

Since the concrete is not poured in 3D printing, but rather applied in extruded strips by a robot, formwork is no longer required, in contrast to conventional concrete construction. The elimination of formwork opens up new freedoms in design with regard to expressive shapes, surface details and cavities. It also enables cost-efficient production of customized components.
 

Modular Fabrication

In the spirit of the circular economy, dismantling is already conceived of so that the White Tower can be rebuilt elsewhere. The modular design allows the individual components to be easily assembled and dismantled. The elements are connected without adhesives, using removable screws.
 

A. Anton / C. Lin / M. Yang
Column fabrication at DBT Group, ETHZ

Setting: The Village of Mul­egns

The village of Mulegns is set high up in the Swiss Alps along the Julier mountain pass. Historically, Mulegns was a stagecoach stopover point for travelers between central Switzerland and the Engadin region, connecting Zurich with St. Moritz. Mulegns was initially a poor village, and many of its inhabitants emigrated to large cities to work as stucateurs and confectioners. The successful ones eventually returned home and built magnificent villas in Mulegns. As tourism began to develop, the village prospered further. At the eve of the first world war, the belle époque Post Hotel Löwe at the center of Mulegns hosted American presidents, Russian nobility, prominent scientists and Nobel Prize winners.

Revitalization

Today the village of Mulegns is threatened with extinction. Many buildings stand empty, and the population has dwindled to 16 inhabitants. The Nova Fundaziun Origen is trying to save the great cultural building stock of the village and trying to revitalize this historic place. The White Villa, which is now under federal protection, was recently rescued by means of a spectacular move. The historic Post Hotel Löwe has been restored and is receiving its first guests again. The White Tower project, as a beacon and haven on the old pass road, will continue writing and reinterpreting the history of this spectacular place.

Point cloud: IGP Group, ETHZ
Tor Alva / White Tower situtated in Mulegns, Switzerland

Project Launch and Timeline

The White Tower project was officially launched by Fundaziun Origen on June 22nd, 2021 in Mulegns, Switzerland. The launch ceremony was attended by Swiss President Guy Parmelin, as well as the President of Graubünden Canton Mario Cavigelli and Surses Municipality President Leo Thomann.

The projected timeline for the White Tower is as follows:

2021 Planning, financing and approval of the tower
2022 Construction of a full-scale demonstration floor
2023 Structural test of reinforced columns
2024 January: Start of 3D fabrication
  May: Assembly of columns in Mulegns
  June: Opening of the tower and first performances
2029 Disassembly of the tower  

Latest News

May 2024: Printing of columns completed, casting of bases, foundation in Mulegns completed.

February 2024: Columns for Tor Alva's first level completed, printing of level 2 commences.

January 2024: Begin of 3D printed fabrication of the tower at ETH in Zurich.

December 2023: Lighting tests on lowest floor of the tower.

September 2023: Stress and deformation testing of final 3D printed column designs. Columns are hollow, rebar-reinforced, and fully structural - a world first.

March 2023: Development and testing of façade systems using ETFE and various membranes. Façade can be removed during warm summer months.

August 2022: The full-scale demonstrator of the tower's third level has been assembled on site in Mulegns. This demonstrator tests the assembly process and connection details, and allows for glazing trials.


Structure: Five levels consisting of 32 3D-printed columns  
  Columns are reinforced and fully structural  
  184 3D-printed elements in total  
Dimensions: Height: 30.0m including an existing base  
  Diameter: 7.0m to 9.0m  
Performance Space: Capacity: 45 visitors  
  Total height: 8.0m, covered by dome  
3D Printing: 2500 extruded concrete layers total  
  8mm layer height, 25mm width  
  Estimated print time: 900 hours  
Façade: Removable ETFE / PVC membrane  
Location: Mulegns, Switzerland; on the Julier Pass  
     
Weisser Turm - Components
  • Architecture
  • Prof. Dr. Benjamin Dillenburger (DBT)
  • Michael Hansmeyer
  • Structural Engineering
  • Prof. Dr. Walter Kaufmann (CSBD)
  • Building Materials
  • Prof. Dr. Robert Flatt (PCBM)
  • Team ETH Zurich
  • Dr. Ana Anton (Research Lead), Elena Skevaki, Che Wei Lin, Ming-Yang Wang,
  • Lena Kitani, Dr. Konrad Grasser (DBT); Dr. Jaime Mata Falcon,
  • Dr. Alexandro Giraldo Soto, Dr. Lukas Gebhard (CSBD); Dr. Timothy Wrangler,
  • Dr. Lex Reiter (PCBM).
  • Project Development
  • Dr. Giovanni Netzer, Nova Fundaziun Origen
  • Team Nova Fundaziun Origen
  • Anja Diener, Rebecca Suenderhauf, Phillip Bühler,
  • Torry Trautmann, Sandro Provino
  • Planning Partners
  • Conzett Bronzini Partner AG - Structural Design,
  • Zindel United - General Contractor