Volume 50, Issue 4 - April 2015
The design, engineering and execution of a recently completed expansion of the Harvard Art Museums required extensive collaboration of all parties involved, including Gartner, the contract glazier, and architectural firms Renzo Piano Building Workshop and Payette.
“Here’s the design: Now go for it.”
Protecting the Goods
“They assisted the team in the development of the design details, ensuring that when the project went into
construction, it would not be held up by the need to revise the design for constructibility or engineering needs,” says Charles Klee, principal at Payette. “This was particularly helpful in the context of selecting glass and specifying insulating glass units that would be able to meet demanding thermal and light transmission requirements.”
Lite it Up
A massive skylight covers the museum and lights up the central courtyard, which utilizes glass walls to introduce more light into the interior spaces. Additionally, two partial glass exterior walls provide views into gallery spaces, as well as views from the building to the surrounding landscape.
“We really had the ability to bring a lot of light down the middle of the building… and the glass in the courtyard brings it further inward,” says Klee. “No matter where you are in the building, you’re always aware of your position (in relation to the courtyard).”
The building’s sloped roof includes louvres and sun-shading devices. The 108-foot-high structure features glass entrances and storefronts, basement and ground floor curtainwalls, a slot curtainwall, a glass canopy and, of course, skylights.
“The development of the rooftop structure was driven by multiple, competing needs,” says Klee. “First and foremost, we were expanding a historically landmarked structure. Any addition to the top of the building needed to be recessive and respectful of the original building. It needed to feel light and delicate to minimize its impact. At the same time, the roof presented a unique opportunity to bring controlled natural light into a building that would generally favor very low levels of light and maximized wall space within the galleries.
“With all of this in mind, glass was a natural choice for the rooftop addition. It was well-received by the two historic commissions involved in the project and offered tremendous opportunities to breathe new life into the central courtyard – the heart of the building.”
The design team dubbed the rooftop assembly “the light machine,” which went on to become a big driver in the reinvention of the museum.
Finely tuned glass in the massive skylight helped strike a balance between natural lighting in the building and protection of the art inside.
Gartner a Partner
Façade consultant Arup provided “a sense of the sizing and performance of the details and systems we are designing,” says Renzo Piano architect Justin Lee. “But with Gartner on board, they were able to marry the design with their fabrication.”
European-based Glas Trösch manufactured the glass, which was fabricated into insulating glass units by German-based BGT. Gartner, meanwhile, fabricated and finished all the steel and aluminum
components of the glazing systems. They were then shipped to Cambridge. Gartner’s U.S. operations provided project management, on-site supervision and worked with the local union members on installation, according to Lee.
“We went through a lot of meetings [with Gartner] to discuss how to put the pieces together, based on their setup in the factory and what they can do efficiently to get to what we wanted,” says Lee. “By getting them on board early, we were also able to fabricate several mockups (both visual and performance) to assist the design process and verify the design performance.”
Gartner was brought in early on the project to assist in the design phase, and several mock-ups were created before the team made its final decisions.
At the suggestion of Renzo Piano, the team built an initial full-size mock-up, which proved instrumental in uncovering issues that would not have surfaced in the design phase otherwise.
“The outer layer of glass being proposed as a shade-protection layer, was lapped with tapered edges to assist in shedding rain water,” says Klee. “The mock-up revealed that the tapered edges acted like mini-prisms, predicting that this roof design would have cast rainbows across the upper floor of the building—and we knew that we had to go back to the drawing board.”
Later in the process, they built a second phase mock-up that allowed for “quantified testing” of the glass and shades so they could calibrate the manufacturer’s data with actual performance. The testing established an important understanding of visible light transmission and solar gain, according to Klee, but that was only the start.
“Working in partnership with the Museum’s world-renowned Straus Center for Conservation, we were able to study the performance of the glass assemblies in terms of their distortion of the transmitted light (color rendering capability) and their transmittance of ultraviolet light,” says Klee. “Both of these were of utmost important when considering the building’s role and the stewardship of the collection.”
When the design was close to being finalized, the architects worked with Gartner and Skanska to complete a performance mock-up, which was tested at the Gartner plant in Gundelfingen, Germany.
There, they ran tests for water infiltration and pressurization leakage. “In this case, we found several conditions that would require special attention during installation to ensure the building achieved the high-performance that was expected,” says Klee.
Because of the glass walls surrounding the courtyard, the skylight’s impact on the courtyard itself made up only a part of the daylighting considerations.
Lee says factors such as the demanding New England climate and the project’s stringent technical requirements “translated to a more close working relationship and involvement with the fabricators.”
While Gartner played a major role, other members of the collaborative effort did, as well—including Skanska and Arup, which contributed services including engineering, lighting design and daylighting, among others.
And with Renzo Piano and Payette collaborating on the project, the design team had created a bit of chemistry amongst itself.
“The way the team worked, it really functioned as a single office,” says Lee. “The Boston team and Italy team were really tied at the hip. It was seamless.”
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