A slight air of unreality hangs over the The Terrace in San Francisco, as if it were an architectural rendering sprung to life. The thin, crisp lines, the expanses of transparency, the slimmest of slim columns are able to capture the ethereality of the initial sketch. On the grounds of the California Academy of Sciences designed by Renzo Piano Building Workshop, the Terrace echoes the elegance of its larger neighbor.
The lineage of glass pavilions is long and illustrious, including Philip Johnson's Glass House in New Canaan, Connecticut, but Cavagnero has pulled off a new architectural feat of strength: 'It's a glass box with two sliding walls in earthquake country,' he says. The $2.7 million rectangular volume, approximately 30 feet wide by 50 feet long, anchors one corner of the museum grounds. Cavagnero's team determined its height by the tallest frameless glass door system'11 feet, 4 inches'it could obtain, a custom system that glides along a recessed track set in the ceiling. The two walls facing the public grounds can disappear completely, while the fixed back wall of frosted glass, bisected horizontally by a clear strip, gives hints of Golden Gate Park beyond. In addition to the glass walls, the interior is brightened by five skylights, which are framed by shadowboxes of blue plastic resin'a clever way to create the illusion of blue skies in foggy San Francisco.
As if ingratiating itself with the larger main building, The Terrace reaches out with its own glass overhang extending from the roof, where recessed structural beams help achieve a thin profile. The design team also figured out how to repurpose the museum's unused concrete former aviary for the caf''s back-of-house operations.
The Terrace seats nearly 90 people indoors, with the patio accommodating another 50, and its floor seamlessly joins the two spaces. Most guests feasting on fare such as roasted asparagus salad and prawn ceviche will be completely oblivious of the structural gymnastics involved: Cavagnero's office worked with Tipping Engineers to put most of the seismic bracing in the roof to minimize shear walls, and used T-shaped beams in lieu of more ponderous I-beams.
Cavagnero also noted Piano's custom design for the Academy's columns and created his own twist: pairs of slender tubes painted white. But anyone seated in The Terrace, particularly when the walls have been folded back, can appreciate the sweeping view. 'Renzo would joke that he didn't like a column to be thicker than his pinky,' says Cavagnero. 'So we'd ask him, 'Is this thin enough?' '
Owner: California Academy of Sciences
Personnel in architect's firm who should receive special credit:
LEED Consulting – Thornton Tomasetti
Renderer(s): Mark Cavagnero Associates
CAD system, project management, or other software used: AutoCad, Sketchup
1,600 square feet
Other cladding unique to this project: Bird safe glazing
Floor and wall tile:Stone Project Skifer – Exterior and interior floors
Interior ambient lighting: Vode