The entrance displays a 7,000 lb, 63 ft long fin whale skeleton that has been part of the museum’s collection for 44 years. Art Gray
The Museum of Natural History of Los Angeles County has added a 65 ft tall glass-enclosed pavilion to showcase one of its most awe-inspiring finds: a 63 ft long fin whale skeleton.
July 9, 2013—The recently completed $13-million Otis Booth Pavilion provides a grand new entrance to the Museum of Natural History of Los Angeles County, which is celebrating its centennial. Displaying a 7,000 lb fin whale skeleton, the boxy, glass-enclosed structure may appear to be an isolated gem, but it is actually the culmination of a lengthy series of improvements that have transformed much of the museum’s Exposition Park campus.
Led by CO Architects and the engineering firm John A. Martin & Associates, Inc. (JAMA), both of Los Angeles, the renovation of the museum has been in progress for years. The original 1913 Beaux-Arts building that constitutes the bulk of the museum was seismically retrofitted between 2006 and 2007. Holes drilled into the exterior walls from the tops to the footings were injected with epoxy grout to reinforce the masonry, and a cast-in-place ring beam was added at the rim line to ties these cores together. Concrete on the roof was replaced with carbon fiber wrap to reduce loads, and a horizontal girder system was installed around the building’s skylights to tie the roof trusses together. This work improved the roof diaphragm and resulted in a seismically sound building that had no visible structural members added to the interior or exterior, maintaining the building’s appearance.
A 1928 addition to the structure also was determined to be seismically vulnerable, as there were no shear walls in the center of the structure and the solid concrete walls that formed its exterior were too stiff. So engineers inserted large shear walls to strengthen the interior while cutting slots 40 ft tall and 8 to 20 ft wide into the exterior walls to make the structure more forgiving during an earthquake, according to Fabian Kremkus, AIA, LEED Green Associate, an associate principal of CO Architects.
The Oits Booth Pavilion is part of a larger upgrade to the Museum
of Natural History of Los Angeles County that included creating a
topographically rich north campus featuring gardens and nature
walks. Courtesy of CO Architects
As that project was being designed, Kremkus saw an opportunity to add more daylight to the museum by fitting the slots with glass curtain walls. “All these little projects that were stacked on this timeline—they kind of served as an inspiration for the staff,” he says. “They could see what was possible with little interventions. It really ramped up the spirits for doing bigger and better things.”
CO Architects was eventually commissioned for just that and was asked to rethink the museum’s grounds and enliven the site by bringing interactive exhibit space outside the buildings. The pavilion project began to unfold, Kremkus says, when funding became available for a new parking garage. The addition of a garage made it possible to eliminate some of the museum’s surface parking, which had created an unattractive back door to the site from Exposition Boulevard.
“We basically freed up 3 acres of landscape around [the museum],” he says. The land on the north side of the building was excavated and regraded so that the museum could offer a topographically rich north campus of gardens and nature walks featuring more than 30,000 new plants. With a new light-rail line stopping just north of the museum, the main entrance was then shifted from the museum’s south side to its north side.
This set the stage for both the enormous, transparent entrance pavilion and a dramatic 129 ft long, arched bridge leading to it. Opened last year, the bridge takes visitors over the new landscaping and into the museum. CO Architects explored several proposals, but Kremkus says the curved design he settled on was inspired by fishing traditions in northern Germany, where he was born. Captains of whaling ships, he explains, were thought of as anchors in those small communities, and when they retired they often placed big jawbones in front of their homesteads. “There is this metaphor—we’re hanging this whale over the entrance,” he says. “Don’t we want to celebrate that as well with the architecture?”
The $13-million pavilion caps a new northern entrance to the
museum, which features an undulating pedestrian arch bridge.
Courtesy of CO Architects
The doubly curved geometry of the bridge members is formed to suggest bones. “Nothing in nature is 100 percent straight,” he adds, and he wanted the shape of the bridge to reflect that idea.
“The bridge we built there is not a typical thing that JAMA would have done,” Kremkus says, adding that he had to negotiate every piece of the bridge’s geometry with Jacqueline Vinkler, S.E., who as a principal of JAMA led the engineering work for the bridge and the pavilion. The bridge design required sophisticated computer modeling. The pipes that form the arches were fabricated by a manufacturer of roller coasters, and they had to be perfectly sized so that they would not show any distortions as they were curved.
And even though the pavilion had not yet been funded, the engineers knew that the bridge would eventually connect to a new structure. “When we were working on the bridge, the one thing I was aware of was that, down the line, the goal was to have this pavilion,” says Vinkler. So she suggested to CO Architects that “we might want to be smart here and already introduce a seismic joint in the bridge that will differentiate between the bridge portion within the pavilion and [the portion] outside the pavilion.”
That joint is seamless, positioned right at the transition point from the bridge to the center of the three-story pavilion, which is roughly 65 ft tall and 65 ft wide. The pavilion itself is seismically joined to an addition dating from the 1970s (a structure also engineered by JAMA). However, Vinkler had to tread carefully to conform to the city’s building codes. “If you start adding too much mass to an existing building, it triggers the building to be retrofitted, and there wasn’t a budget to do that,” she says.
Trusses connect to four of the pavilion’s columns, two on each
side. The remaining columns tie in to the bridge. Courtesy of
The glass-clad pavilion structure is basically six columns plus a roof. To keep the load under the threshold that would have triggered a retrofit, JAMA devised in-plane trusses that radiate from the existing building to the pavilion so as to engage and help support and stiffen the columns and at the same time allow loads to be evenly distributed. The trusses connect to four of the pavilion’s columns (two on each side), while the pair of columns at the front of the pavilion tie in to the bridge.
Vinkler says while the engineers could have seismically separated the glass box, such an approach would have created its own challenges. “You would have had a much more massive lateral system,” she says, but that would have required larger structural members, which in turn would have obstructed views through the pavilion. “And then you’d have these ugly, 60-foot-tall seismic joints that are also costly,” Vinkler says, “and are not one of the favorite things that architects like to detail.”
There was also complexity in the columns themselves, which curve inward at the top of the pavilion. The design team deliberated on how to build them, where to put the splices, and where to find the necessary pieces. They also had to consider how to join the existing structure with the glass curtain wall, which uses 139,000 lb of glass. “We had to understand how the loads were going to be imposed to the structure and to ensure, relative to the seismic movements of the structure, that their systems could accommodate it,” Vinkler explains. JAMA tweaked the pavilion structure to accommodate the points of attachment of the curtain wall.
On the rear wall and roof of the pavilion, a membrane of translucent
PVC film backlit with LED lights provides acoustic dampening and
a customizable visual experience. Art Gray
The pavilion displays the 63 ft long skeleton, which has been part of the museum’s collection since 1944. The space is grand enough that the skeleton, which is positioned diagonally, can be seen from the light-rail station. What is more, the head of the skeleton comes within 8 or 9 ft of the bridge on the pavilion’s middle level, enabling visitors to get a closer look as they pass through and enter the museum.
For the ceiling and back wall of the pavilion, CO Architects considered a series of metal panels that would display images suggestive of the sea. That would have been fine, says Kremkus, but it wouldn’t have given the museum much flexibility, since the images would have been permanent. “I didn’t feel it lived up to the actual opportunity that was given here,” he says.
So he began looking at animated solutions. He turned to translucent polyvinyl chloride (PVC) film that could be stretched over an aluminum profile. Microscopic perforations in the membrane allow acoustic damping and the placement of insulation behind the membrane. And the membrane can be backlit with light-emitting diodes (LEDs), making it possible to change the appearance. The skin has been outfitted with more than 33,000 red, blue, green, and white LEDs. The system, Kremkus says, is capable of rendering 2 million colors, enabling the pavilion to display still or moving images.