Banner photo courtesy of Ben Rose Photography
By Kirk Stelsel, CAE
When Jeff Bezos – the man who disrupted the shopping industry with Amazon and spends $1 billion a year on his Blue Origin project – stopped to admire a freestanding precast concrete structure known as the MARS Pavilion, he told one of the designers, “That pavilion, it’s insane and insane is the best compliment I can give.”
What about this concrete structure caught the fancy of the richest man in the world? The structure itself is only part of the answer. The story behind its fabrication is much more complex, and therein lies the odyssey of two entrepreneurs who set out to reinvent custom precast concrete.
Chapter 1: An idea takes shape
Inspiration often strikes fast. For Ron Culver, AIA, and Joseph Sarafian, Assoc. AIA, LEED GA, it came at a technology seminar while pursuing their Master of Architecture degrees at UCLA. The two began to wonder how they could use programmable robots in tandem with fabric forms to create unique concrete shapes. Individuals like Mark West and Andrew Kudless, leaders in fabric-formed concrete, inspired their direction. With their plan in mind, Culver and Sarafian created Form Found Design and set out to realize their vision.
“Our intention is to change the paradigm for concrete casting in the architecture and construction industry,” Culver said. “We looked at a number of different ways to create adjustable forms but we arrived at this because we thought robotics would allow us to go from digital to physical in a way that isn’t being done yet. It’s demountable, reconfigurable, low weight, rapidly customizable and able to manage complex geometry without complex formwork, so it’s a very low cost to create mass customization.”
The two had to overcome many early challenges, such as how to connect the fabric to the robots, accurately position points in space to suspend the fabric, connect the pieces and reinforce the concrete.
They conducted early experiments with glass-fiber reinforcing, but as the duo scaled up they realized they needed something else in order to create a self-supporting structure. Traditional reinforcement wasn’t feasible for the shapes, which led them to use Helix Steel’s Twisted Steel Micro Rebar.
During the research and development process, the two gave a talk in Sydney, Australia, in front of others experimenting in the robotics niche of architecture. There, they met Steve Fuchs, who had experience using robotics and high-end digital software for world-famous architect Frank Gehry’s office. Fuchs soon became a part of the team, along with interns Andrew Lindauer from Orange Coast College in Costa Mesa, Calif., and David Spiva from Cal Poly in San Luis Obispo, Calif.
Chapter 2: Amazon comes calling
As the team’s work progressed, it gained the interest of influential people, including representatives connected to Bezos. Each year, he convenes a conference in Palm Springs, Calif., named MARS for machine learning, home automation, robotics and space exploration. The invite-only event features cutting-edge technology, so the world’s first robotically-cast concrete pavilion fit in well.
“Amazon taps some of the most provocative emerging technologies and brings them together to inspire each other for one exciting weekend,” Sarafian said. “They brought us on and asked how big we could go with our technology. We sent them a few renderings showing a 6-foot-tall structure and they wanted to go bigger and have a large impact on the conference.”
After scaling up to 14 feet tall, the team realized they needed to call in engineering reinforcements. Steve Lewis, Ph.D., P.E., FRSA; Kais Al Rawi, JEA; and Cheryl Luo of Walter P. Moore Engineering came on board for the project and the team began to look at geometries that would take advantage of the inherent strengths of concrete, primarily its compressive strength properties.
Using a Rhino 3-D model and gravity simulator software Kangaroo3D, the team landed on a catenary structure based on the way gravity affects fabric hung from four points. In the dome-shaped design, nearly every element was in compression.Before construction, Lewis and the engineers at Walter P. Moore analyzed the structure using finite element program Strand 7 to rationalize the elements in 3-D and determine the stresses and forces on each.
“We had a good form in that it was optimized to carry axial compressive loads, so we took the design model, which is more about geometry, and revised it,” Lewis said. “First, we had to create a rationalized mesh geometry that we would be able to use in the program and then we had to come up with a digital workflow where we could iterate through different design models and ensure we could connect the wishbone elements together. At WPM, we embrace the philosophy of digital workflow where we strive to embrace digital technology as a means to facilitate meaningful collaboration with our clients.”
“The analysis model we did was really high-fidelity,” Sarafian added. “It had almost 600,000 elements. Instead of looking at the whole pavilion as an entire structure and analyzing the loads acting on it all at once, finite element analysis is basically treating each component like its own building.”
Using this analysis, the team assigned loads and looked at the stresses on the elements, how they deflected and how the structure would perform. In instances where the stresses were too high, Lewis communicated with Culver and Sarafian and suggested options such as increasing the cross-sectional diameter or refining the design to add more wishbone elements.
“The ability to generate a high-fidelity digital analysis model where the local stress could be boiled down to two numbers of principal stress of compression and tension was essential as the structure had no distinct load path that described not just gravity or vertical loads, but also lateral loads,” Lewis said.
Without the integrated, high-fidelity digital workflow, the engineering team likely would have needed to simplify the structure in order to understand its structural behavior and feel comfortable with its strength and stability. Such an approach would have compromised the aesthetic vision and also potentially led to a less-than-optimal, heavy structure.
In addition, although a temporary structure, it was located in a seismic zone and consideration of lateral seismic loads was required. This revealed more significant tensile load paths that had to be considered. The assessment included not only the concrete elements, but also how the load was transferred locally at the node anchor embed. Iterations were needed to optimize the connection locally to increase the pullout capacity of the connection. The digital analysis model allowed the team to obtain the pullout demands efficiently.
Chapter 3: Showtime
After months of R&D, the team anxiously started casting the elements for the pavilion. First, they made sure they had the process set up precisely and that the robots were accurately calibrated. They spent a lot of time establishing tolerances and ensuring every last aspect was accurate. That work paid dividends. Production ran smoothly with very few issues.
“The first month was really just troubleshooting and creating a system that had never really been built out before,” Sarafian said. “Early on, we were casting one per day and by the end we were casting about eight per day.”
At the MARS conference, they assembled the 70 unique elements over the course of three days with precision levels of 1/16 of an inch. The final structure was not only self-supporting, but structurally redundant. Any element could fail and the surrounding elements would assume the additional loads imposed. The team was proud of the fact that although it was the first of its kind, the project came in on time and on budget. Just six months prior, the project was only renderings. Now, their structure was ready to be seen.
“It was a testament to the team and how hard we were willing to work,” Sarafian said. “I’ve never worked harder in my life, and our engineering team worked tirelessly to meet our demanding schedule and unique project goals. It was a lesson for us in learning how to be relentless.”
Chapter 4: The future
After premiering at the MARS conference, the pavilion was sent to the A+D Museum in Downtown Los Angeles as a temporary exhibit. It has now been disassembled and the team is focusing on how their innovative system can be used in real-world applications.
After the initial publication of the project, two major architecture firms reached out to Form Found Design to ask for product information. This was the validation the team needed.
“There are firms out there that see this as a solution to something they are designing,” Sarafian said. “The idea is we can build this out as a facade system that could introduce variation without the added cost of variation. We would like to roll out a system and web app that would allow a user to toggle certain presets and design their own facade with our product.”
They are currently gearing up to build the first prototype of a facade system they aim to complete by December 2018. It will be similar to past work, but robust enough to take on all the new challenges of scale.
To tackle this next hurdle, they will rely on mentors like Ken Vallens of CTS Rapid Set and Luke Pinkerton of Helix Steel to take on the challenges of commercialization. Just as they focused on preparation before casting the MARS Pavilion elements, they are proceeding deliberately as they know their early decisions will dramatically affect their success down the road.
There is a lot of work left to be done, but the Form Found Design team embraces the process. If their ability to overcome challenges and catch the eye of Bezos and major architecture firms is any indication, they are up to the task.
Kirk Stelsel, CAE, is NPCA’s director of communication.