The snowball is starting to roll. Composites are beginning to catch on in the world of architecture. A recent project near Detroit, MI – a tall, thin, other-worldly black egg – illustrates how things are starting to move, why they’re going slowly, and how it will continue to grow.
Lawrence Technological University (LTU) was founded in 1932 by Russell E. Lawrence, with assistance from Henry and Edsel Ford. Ford gave the fledgling institution a building adjacent to the High Park Ford plant, the landmark manufacturing facility that was designed by fabled Detroit architects Albert Kahn Associates. LTU moved to Southfield, MI in 1955.
The most recent addition to the Southfield campus is the A. Alfred Taubman Complex. This 36,600-square-foot building is the home of the new Marburger STEM Center, in addition to laboratories and collaboration spaces for biomedical engineering, robotics, life sciences research, and the university’s SAE motorsports teams. The Taubman Complex cost almost $17 million.
At the center of the Taubman complex is an architectural element that will likely become the signature of the complex, a 42-foot tall enclosed staircase that floats above a reflecting pool. DeMaria Building Company, the general contractor for the Taubman Complex selected Construct, aka Architectural Composites, LLC, a division of Advanced Technology International (ATI) to engineer, fabricate, and install this black, egg-like enclosure made of fiber reinforced polymer (FRP).
The staircase is supported by a steel construction made of ½” welded plates that form columns at the perimeter. The stairs are cantilevered from these columns, and never touch the ground. This steel stair is enclosed in a composite shell with a cross-section that is round at the top, but transitions to elliptical as you decrease elevation. The shell does not touch the ground either. The entire structure hangs over a reflecting pool that emphasizes its apparent weightlessness.
We recently talked with Aleksander Tamm-Seitz, Morphosis’ Project Architect for the Taubman Center, and Mark Snider, Chief Engineer for Construct, about the genesis of the staircase and how it was executed.
According to Tamm-Seitz, who spent about 2 years solid on the Taubman Complex, Morphosis’ Design Director Thom Mayne wanted to make the building in the spirit of buildings designed by the Kahn firm, such as the Ford Model-T factory. Mayne “was interested in trying to make it almost a contemporary Albert Kahn building, using a lot of those ideas that they had in the 20s and 30s, where everything was exposed and rough, but still very aligned and very clean.”
Mayne was also, more generally, on the lookout for a project where they could work with composite materials in a substantial way. Mayne and his team learned something about composite design and fabrication when they visited the Santa Ana, CA facility where Greg Lynn was building an all-carbon fiber boat.
“When we started looking at composites for this project, we already had [designed] a stair piece that was a kind of social hub for the building,” explains Tamm-Seitz. “We knew we needed something as light as possible. At the same time, architecturally, we were looking for something very monolithic that wouldn’t be a panelized system where you would see a lot of joints and seams. We didn’t want a metal panel system or rainscreen. We really wanted it to read “monolith,” an eggshell hovering off the side of the building. FRP made a lot of sense for that, because we knew we’d be making these very large pieces, as large as you could transport on a truck.”
In the beginning, they were very interested in the idea of an all-carbon fiber structure. It seemed to speak to a spirit of technical innovation that felt appropriate for the institution. As Morphosis began engineering the piece, it became evident that the decisions that might drive carbon fiber design in a boat (strength-to-weight ratio) didn’t really make sense in a building, where weight was not as critical a question. They began looking at a carbon fiber/glass fiber combination, which would save some of the material expense of carbon fiber construction.
Through talking with composite fabricators such as Kreysler and Associates (full disclosure: sponsors of this blog), they also became aware that fire resistance and code approval was going to be a significant issue. “It’s probably one of the main reasons you don’t see a lot of architects using this building material,” comments Tamm-Seitz. “The NFPA 285 test,” the standard for code approval when using a material that is not fire-rated “requires that you have an approved wall assembly that meets these tests, and if you don’t already have a tested assembly, you have to test it yourself, which is very expensive.”
They considered using Kreysler’s Fireshield 285 system, which had previously been tested and passed for use on the façade of the new expansion of the San Francisco Museum of Modern Art (SFMOMA). However, since Fireshield 285 is a proprietary system, that would have left only one fabricator to bid on the project, eliminating the possibility of competitive bids. Institutional clients such as LTU want multiple bids, and they have to come from companies big enough to be bonded for an expensive project. In the very small world of architectural composites, it was not easy to find enough qualified bidders who were willing to go to the high expense of building a mockup and performing the NFPA 285 burn test.
When it came to selling the composite concept to the client, the degree to which construction is a cumulative science became evident. “If Kreysler hadn’t been so far along with the SFMOMA building, and proved that you could do the NFPA test, we probably couldn’t have done this,” recalls Tamm-Seitz. “But since Kreysler had done that heavy lifting, we were able to show that [SFMOMA] to our client and the [Lawrence Tech] board members, and that really helped. It wasn’t seen as some crazy process that is used for boats and not for buildings.” Tamm-Seitz also credits Kreysler for helping “with our specs and what we needed to include in our bid documents.”
When the project was put out to bid, another company stepped up that was attracted to the project precisely because they had substantial expertise in composites and felt that it was underutilized in the architectural space. Construct is a division of ATI that was formed to apply their defense-related composites expertise and partner network to the architectural world. They had previously designed large composite ceiling tiles for the Javits Center in New York City.
“The biggest challenge,” recalls Construct Chief Engineer Mark Snider, “was that we had to develop a laminate that would structurally be self-supporting, having minimal attachment points to the stairwell – and then to find the recipe that meets this very stringent fire code problem that wasn’t too cost prohibitive. It pretty much drove us to using a phenolic resin system.”
Phenolic resin is a relatively old synthetic plastic, dating back to the early 20th century. It is made from phenol (aka carbolic acid, a coal tar or petroleum derivative) and formaldehyde (a wood derivative). Phenolic resin was the basis for Bakelite, the first fiber reinforced polymer (made with wood and asbestos fibers) patented in 1909, and used for its easy and precise moldability. Phenolic resin has high heat resistance, and was the dominant material of circuit boards in the days of tube-powered radios and TVs.
“It’s an established system, and it works well in certain applications”, comments Snider. “When fire and smoke is involved, it’s a really robust system to use.”
Phenolic resin is usually orange or brown in color, and largely opaque. Since the resin would completely conceal the fibers of the composite, and there was really no structural need for the strength greater than glass fiber, the carbon fiber concept was eventually abandoned. The final product was made entirely using glass fiber reinforcement and then painted black.
“We resin-infused the panels using Cellobond J2027 phenolic resin,” relates Snider. “We had to find suppliers that were capable of fabricating it. We designed it based on the specs given, and then worked with JRL Ventures, recently rebranded as Marine Concepts / Design Concepts, a very big boat-maker, to develop the mold strategy.
“We created one mold that was used for all five panels. A couple had unique cutouts and scribe lines, for the interface to the stairwell opening, that were cut in the mold. Design Concepts / Marine Concepts subcontracted with Composites Consulting Group (CCG) to develop the infusion strategy, so it would get fully infused before everything started to kick, and developed a temporary oven that was built around the mold to cure it.”
NFPA 285 fire tests were conducted with a mockup 18ft tall and 14ft wide, made of flat panels that replicated the laminate schedules, flange interfaces, and acoustical plaster system on the inside. The test assembly was fabricated, painted and prepped exactly as in the application.
“The fire test was expensive,” confesses Snider. “It was an investment, but we now have a certified and listed structural laminate that we could use ourselves or license to other parties for building applications that need the high fire performance.”
The shell (or “Orb” as Construct came to call it) was molded in five panels, an optimization of the number of parts to be made vs. the challenges of shipping large pieces and installation. The panels have an integral flange molded onto the sides, and they simply bolt together. There are metal rings and brackets that interface to the skylight and at the bottom, which supports a polycarbonate floor that looks down into the reflecting pond below.
The cross-section of the orb evolves as you change elevation – circular at the top but transitions to elliptical as you move down. Construct took a novel approach to this aspect, too. “It was molded as though it had a varying circular cross sectional shape throughout the elevation, which allowed us to optimize tool usage. We then squeezed the assembly as we installed it to the desired shape.”
Installation was very challenging, because at least two of the panels had to be installed in a very tight space with extremely limited access. “The stairwell structure and primary building panels surrounding the upper portion of the Orb were already in place when it was our turn to install the panels, in some places we had less than a foot to maneuver the panels between the attachment flanges and the building. We were fortunate in that we hired a great installer, C.L Rieckhoff who was able to do this without damaging the Orb panels or any building panels, all the while doing this in sub-freezing weather and less-than-ideal wind conditions” says Snider.
“We started at the building and worked our way out. Each piece has brackets that hold the shape where it needs to be in X/Y/Z coordinates. Due to the Orb’s extremely tight attachment to the building, our installer C.L. Rieckhoff brought in a specialist to rappel down between orb and building to access hardware, to bolt the first couple of panels in place. Once we got all the parts together, the bottom was the most challenging, the polycarbonate floor frame that we had to get everything to line up.”
Completion of the Taubman Center overall is expected this month.
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“It’s definitely a material where a lot of study is relevant,” reflects Aleksander Tamm-Seitz. “It’s very much in its infancy. It was difficult to find a lot of examples of where this stuff had been used on the type of thing were trying to do, using a material like this as a building enclosure. Obviously, we’ve used fiberglass on other projects, but it’s been more decorative in nature. This was one of the first projects where it was moving towards being a building material, towards enclosing the building, and there are a huge number of requirements that come along with that.
“It’s very early. People are still learning what are the potentials of this material. If we’re doing a concrete building, we already know the rules, we know how to rationalize the facade so they can re-use formwork, etc. It’s already known and done, and it’s an industry standard. Does it matter if you can reuse the formwork [for composites]? Does it matter if the shape is rational? They’re still learning.”
Images via Morphosis, Albert Kahn Aassoc., Construct LLC, and DeMaria Building, as noted.