“The success of the installation shows the impact that robotic solutions can have on the construction industry—they’re not just stacking vertical walls, but also creating complex shapes.” —Juror June Grant

Humans and robots have worked side by side in the automotive industry since the 1960s. With modern robotics, architects and engineers are now testing advanced models of enhanced construction and fabrication.

The Glass Vault project, a collaborative effort by Skidmore, Owings & Merrill, Princeton University’s CREATE Laboratory and Form Finding Lab, and TU Delft Glass & Transparency Research Group, is a notable example. Two human-scale, fixed-in-place robotic arms, provided by Global Robots and assisted by humans, can assemble a self-supporting, doubly curved, and visually stunning masonry shell 7 feet tall, 12 feet wide, and 21 feet long.

Also known as a timbrel vault, the thin and highly efficient structural system comprises a series of masonry arches that carry loads in compression. Building such a vault is labor intensive, but leveraging robotics may change this. “Our research focuses on how robots and humans can collaborate to achieve structures that each cannot build alone,” says CREATE Laboratory director and assistant professor of architecture Stefana Parascho.

Testing prototypes of different materials and scales, leading to the final robotic construction of the Glass Vault at the University of Westminster
Isla Xi Han, Shenhan Zhu, and Edvard Bruun, Princeton University CREATE Laboratory and Form Finding Lab Testing prototypes of different materials and scales, leading to the final robotic construction of the Glass Vault at the University of Westminster

The robots begin by constructing a single arch at the vault midspan. One robot uses an angled gripper to act as centering while the other robot positions and adheres the next brick. The robots alternate tasks until the first arch is complete and self-supporting. The robots then work separately to build out the vault in opposite directions. Meanwhile, humans serve as mason tenders, adding bonding material—rigid epoxy—to each brick. “Stabilizing an almost fully constructed arch would be difficult for a human to do, but robots are built for exactly these tasks: providing support and precision,” Parascho says. “Applying mortar or glue is a simple task for a human but would require vision or other sensors if performed by a robot. This is why we divide the work.”

The overall form of the Glass Vault is intentionally asymmetric to prevent the robot’s “elbows” from clashing while building the arch. The Princeton researchers tested several prototypes to identify one successful form achievable through meticulous choreography.

The construction sequence of the Glass Vault was inspired by an ancient barrel vault technique that relied on inclined courses set against a vertical end wall to construct vaults without centering.
Isla Xi Han/Princeton University CREATE Laboratory The construction sequence of the Glass Vault was inspired by an ancient barrel vault technique that relied on inclined courses set against a vertical end wall to construct vaults without centering.

The transparent glass bricks, supplied by Poesia Glass Studio, are 10 times stronger in compression than their clay counterparts. All 338 units are the same size, yet their positioning creates joints that range from approximately 0.25 inch to 0.5 inch. For the larger joints, the human steps in to add a small acrylic filler. By allowing robots to do what they are good at—precise, repetitive tasks—and humans to handle the judgment calls, this construction process is the modern version of craftsmanship.

The final prototype was assembled before an audience during the March 2020 exhibition “Anatomy of Structure: The Future of Art + Architecture” at the University of Westminster’s Ambika P3 gallery, in London. The team of robots and humans completed the Glass Vault in two weeks, working only during exhibition hours.

”Imagine," says SOM structural and seismic engineering partner Mark Sarkisian, “using this same kind of philosophy on large-scale construction where structures are being built in an automated way."

Timelapse: Glass vault construction

The construction of the Glass Vault allows architects and engineers to imagine a new range of possibilities that merge robotic capabilities and human ingenuity, according to the project team.
Maciej Grzeskowiak/Skidmore, Owings & Merrill The construction of the Glass Vault allows architects and engineers to imagine a new range of possibilities that merge robotic capabilities and human ingenuity, according to the project team.
Robotic arms' areas of reach
Isla Xi Han/Princeton University CREATE Laboratory Robotic arms' areas of reach
Digital modeling helped the design team determine the efficient, doubly curved, compression-only shape of the vault structure.
Isla Xi Han/Princeton University CREATE Laboratory Digital modeling helped the design team determine the efficient, doubly curved, compression-only shape of the vault structure.
The project team identified a fast-setting and rigid bonding material that also had enough tensile capacity to hold a glass brick in place in the temporary construction condition.
Isla Xi Han/Princeton University CREATE Laboratory The project team identified a fast-setting and rigid bonding material that also had enough tensile capacity to hold a glass brick in place in the temporary construction condition.
To enhance constructability and reduce material quantities, the Glass Vault uses no temporary falsework structures.
Isla Xi Han/Princeton University CREATE Laboratory To enhance constructability and reduce material quantities, the Glass Vault uses no temporary falsework structures.
First Glass Vault prototype testing, almost close to full scale
Isla Xi Han/Princeton University CREATE Laboratory First Glass Vault prototype testing, almost close to full scale
Robotic arms constructing the initial arch of the Glass Vault
Isla Xi Han and Edvard Bruun, Princeton University CREATE Laboratory and Form Finding Lab Robotic arms constructing the initial arch of the Glass Vault
The vault shape was conceived to showcase the robots’ capabilities, particularly in spatial awareness.
Maciej Grzeskowiak/Skidmore, Owings & Merrill The vault shape was conceived to showcase the robots’ capabilities, particularly in spatial awareness.
Detail view, Glass Vault
Maciej Grzeskowiak/Skidmore, Owings & Merrill Detail view, Glass Vault
The herringbone pattern was selected for its inherent structural properties.
Isla Xi Han and Edvard Bruun, Princeton University CREATE Laboratory and Form Finding Lab The herringbone pattern was selected for its inherent structural properties.
By using standardized bricks of the same dimensions, the team avoided field cutting complex brick shapes and fulfilled the aspirational requirement of simplified construction.
Maciej Grzeskowiak/Skidmore, Owings & Merrill By using standardized bricks of the same dimensions, the team avoided field cutting complex brick shapes and fulfilled the aspirational requirement of simplified construction.
The vault geometry was defined to minimize tensile forces within the structure.
Maciej Grzeskowiak/Skidmore, Owings & Merrill The vault geometry was defined to minimize tensile forces within the structure.

Project Credits
Project: Robotic Construction | The Glass Vault
Location: Ambika Gallery, University of Westminster, London
Research and Implementation Teams: Skidmore, Owings & Merrill, London, New York, San Francisco, Chicago . Mark Sarkisian (seismic and structural engineering partner), David Horos (director of structural engineering), Dmitri Jajich (director of structural engineering), Alessandro Beghini, Stuart Marsh (structural engineering associate directors), Michael Cascio (project manager), Samantha Walker (professional engineer), Matteo Tavano, Arthur Sauvin, Max Cooper (senior structural engineers), Arthur Sauvin (structural engineer), Masaaki Miki (architect); Princeton University’s CREATE Laboratory and Form Finding Lab, Princeton, N.J. . Stefana Parascho (CREATE Laboratory director), Sigrid M. Adriaenss (Form Finding Lab director), Isla Xi Han, Edvard P.G. Bruun, Ian Ting, Lisa Ramsburg, Chase Galis (CREATE Laboratory); TU Delft Glass & Transparency Research Group, Delft, the Netherlands . Faidra Oikonomopoulou, Telesilla Bristogianni
Architect of Record: Skidmore, Owings & Merrill
Structural Engineer: Skidmore, Owings & Merrill

Materials and Sources
Glass: Poesia Glass Studio
Robotic Arms: Global Robots