Tor Alva — the world-tallest 3D-printed concrete tower

Mulegns, Switzerland

A New Chapter in 3D-Printed Concrete Construction

Rising gracefully from the dramatic landscape of the Swiss Alps, Tor Alva—or The White Tower—is rewriting the rules of construction. As the world’s first multi-story structure built from load-bearing reinforced 3D-printed concrete columns, it represents a milestone in digital fabrication with concrete and structural engineering.

Since its early days, 3D-printed concrete (3DPC) was relegated to producing non-structural elements—ornamental elements, lost formwork, decorative facades, or low-demand walls such as masonry walls. This limitation wasn’t due to lack of vision, but rather due to fundamental technical challenges: no structural models accounted for the anisotropic nature of layered printed concrete, and there was no proven method for reinforcement integration in a way that ensured structural integrity.

But that’s changing—thanks in large part to the pioneering work behind Tor Alva.

 

Architectural and Technical Highlights of Tor Alva

Tor Alva, stands at an impressive 30 meters high, with a diameter of 7–9 meters, creating a striking vertical presence in the alpine landscape. The 3D-printed concrete structure is composed of four floors plus a dome, supported by 32 uniquely shaped hollow columns.

Visitors can climb the tower via a spiral staircase comprising 98 steps, which leads to the upper upper viewing platform, which not only offers breathtaking panoramic views of the valley but also serves as a venue for cultural events, continuing the tower’s role as both an architectural and artistic landmark.

The tower’s columns were produced using 3D-printed concrete, applied layer by layer at a width of 25 mm and a thickness of approximately 7 mm. Each of the 32 columns follows a continuous printing trajectory of around 5’000 metres, resulting in an overall total length of approximately 210 kilometres of printed material. Altogether, the construction involved more than 2’500 individual layers and required around 900 hours of printing time.

Despite its monumental scale, Tor Alva—also known as the White Tower—is a prime example of circular and modular architecture. Designed to be fully demountable, the structure can be disassembled and reassembled at a different location. For now, it is planned to remain in Mulegns for a period of five years, serving as a cultural and architectural beacon in the Swiss Alps.

From Vision to Full-Scale Structural Application

Tor Alva is the result of an extraordinary alliance between cutting-edge research, visionary architecture, and skilled industry partners. Led by the Nova Fundaziun Origen, the project brings together an outstanding team from ETH Zurich, the National Centre of Competence in Research (NCCR) Digital Fabrication, and key collaborators from the construction and engineering industries.research, visionary architecture, and skilled industry partners.

Through intensive research on the material performance, full-scale testing, and the development of new mechanical models, the structural team behind Tor Alva has managed to bridge a crucial gap. They developed a new test—the Modified Slant Shear Test—to quantify the performance of 3D-printed concrete including the influence of the 3D-printed concrete layer interfaces, especially those weakened by printing time gaps. Moreover, multiple experimental campaigns validated how steel reinforcement and prestressing could be reliably integrated into the printed material, including reinforced 3D-printed concrete tie tests that investigated the interaction between the steel reinforcement and the 3D-printed concrete.

The result? A 30-meter-tall tower made of hollow, 3D-printed concrete columns that are not just decorative—but load-bearing.

Laying the Groundwork for Standards

What makes this achievement even more significant is the lack of current standards for designing with 3D-printed concrete. Its unique, layered nature introduces complexity that existing codes simply don’t address.

Since this type of structural system is not yet covered by building codes, it was necessary to conduct full-scale tests to validate the structural integrity of the Tor Alva’s columns. The experimental campaigns are contributing directly to developing mechanical models and design principles that can inform future building codes. In doing so, the project opens the door to standardisation and, ultimately, to the broader adoption of this promising construction technology.

Unveiling a Global First

On May 19, 2025, the White Tower—standing proudly at around 30 meters tall—was revealed in a dramatic unveiling ceremony, where a helicopter lifted the protective cover that had shrouded the structure during its final phase. This breathtaking moment, captured on video, marked the public’s first full view of the completed tower.

The official opening ceremony took place on May 20, 2025, featuring distinguished guests including Guy Parmelin, member of the Swiss Federal Council since 2016 and head of the Federal Department of Economic Affairs, Education and Research (EAER), as well as Dr. Jon Domenic Parolini, head of the Department of Education, Culture, and Environmental Protection and former President of the Cantonal Government (Regierungspräsident). The event celebrated not only a technical and architectural milestone, but also a cultural moment that reflects the spirit of innovation and collaboration at the heart of the Swiss Alps.

Project collaborators

Nova Fundaziun Origen

Client
Nova Fundaziun Origen, under the artistic direction of Dr. Giovanni Netzer

Client Team
Anja Diener, Rebecca Suenderhauf, Philipp Bühler, Torry Trautmann, Sandro Pirovino

Site Management
Invias AG – Diego Casparin
Nova Fundaziun Origen – Anja Diener

Master Builders
Zindel + Co. AG (Zindel United) – Nico Russi
Battaglia Bau AG (Uffer Group) – Sascha Pittet

Structural Engineering
Conzett Bronzini Partner AG – Jürg Conzett

Building Physics
mk bauphysik – Martin Kant

ETH Zurich

Architecture
Prof. Dr. Benjamin Dillenburger, Digital Building Technologies (DBT)
Michael Hansmeyer
Research Team:
Dr. Ana Anton (Research Lead), Eleni Skevaki, Che Wei Lin, Ming-Yang Wang, Lena Kitani, Su Huang,
Dr. Konrad Graser (ZHAW Institute of Construction Technology and Processes – Project Coordination)

Structural Design
Prof. Dr. Walter Kaufmann, Institute of Structural Engineering (IBK)
Team: Dr. Alejandro Giraldo Soto, Dr. Lukas Gebhard, Dr. Lucia Licciardello

Building Materials
Prof. Dr. Robert Flatt, Institute for Building Materials
Team: Dr. Timothy Wangler, Dr. Lex Reiter

Geodesy
Prof. Dr. Andreas Wieser, Geosensors and Engineering Geodesy (GSEG)

Robotic Fabrication Laboratory
Mike Lyrenmann, Philippe Fleischmann, Tobias Hartmann, Luca Petrus, Jonathan Leu

Global Partner

ETH-FOUNDATION

ETH ZÜRICH

UFFER GRUPPE

ZINDEL UNITED

Publications

Giraldo Soto, A., et al. “Fully load-bearing reinforced 3D printed concrete and its application in Tor Alva, the world-tallest 3D printed concrete tower”. Hormigón y Acero. Accepted for the IX Congreso Internacional de Estructuras, 2025.

Licciardello, L., et al. “Determining the strength of 3D printed concrete with the modified slant shear test”. Structural Concrete, 2025. https://doi.org/10.1002/suco.202400238

Anton, A., et al. “Tor Alva, a 3D Concrete Printed Tower” In: Fabricate 2024: Creating Resourceful Futures, 2024. https://doi.org/10.2307/jj.11374766.35

Giraldo Soto, A., et al.: “Structural Testing Campaign for a 30 m Tall 3D Printed Concrete Tower”. In: Fourth RILEM International Conference on Concrete and Digital Fabrication, 2024. https://doi.org/10.1007/978-3-031-70031-6_57