When it comes to pushing the design limits of architectural glass, there are few risk-takers quite like Apple. The tech giant first grabbed the architectural world’s attention in 2002 with the glass staircase at its Soho retail store in New York, and hasn’t slowed down. Many of the company’s retail locations around the world are testaments of what’s possible with structural glass. The recently completed Steve Jobs Theatre, part of the Apple Park Campus in Cupertino, Calif., is no exception. The campus represents an eight-year collaboration between Apple and architectural firm Foster + Partners.
“Right at the outset, Steve stressed that Apple Park should have its own theater for 1,000 people. He set in place the sequence of spaces–lobby, theater, and hands-on space–that define the building,” says Norman Foster, founder and executive chairman of Foster + Partners. “He wanted just the lobby to be visible and for it to be discovered like a ‘jewel’ in the park. To achieve this, we submerged the rest of the structure, creating a delicate relationship between the lobby and landscape with a deliberate element of surprise within.”
Spanning the Limits
The circular theatre is constructed with large, finless structural glass walls that support a carbon fiber roof in a seismic zone. The roof rests on a transparent 22-foot-tall and 135-foot- diameter glass cylinder. According to a Foster+Partners release, while the roof appears to float effortlessly, it is actually the largest carbon-fiber roof in the world, weighing 80.7 tons. The roof has a 155-foot diameter and spans 135 feet between the glass walls, making it large enough to completely cover a Boeing 757 airplane. With each section averaging 70 feet long and 11 feet wide, the entire roof assembly can be compared to a network of 44 yachts arranged in a circle, according to the architects.
The thin roof disc comprises 44 identical radial panels, which were assembled on-site and arefully craned into position onto the completed glass cylinder in a single lift. All its services, such as electric conduits and sprinkler pipes, are invisibly integrated within the thin silicone joints between the curved glass panels.
“Pushing the limits of materiality even further, just four layers of glass form the structural support. The glass is all that holds up the roof–there are no single columns. It is the largest all glass-supported structure in the world,” reads the release.
All in the Details
The glass for the project was fabricated and installed by the Italian company Frener & Reifer. Eckersley O’Callaghan (EOC) was the structural engineer. Since Cupertino is in a highly seismic zone, the structural criteria were particularly challenging given the properties of glass and required detailed analysis to fully justify safe design.
EOC says it employed a number of strategies in the event of seismic activity such as keeping the weight of the roof to a minimum. “The curved glass panels are fixed at their base with the innovative use of structural silicone into a steel clamp detail, which absorbs the energy of an earthquake. The steel clamps are engineered to “deform” before the glass breaks, safeguarding the integrity and robustness of the overall structure,” reads information on the firm’s website. EOC also worked closely with the architects to engineer and design the glass elevator that spans 42 feet in height, and corkscrews as it descends to the lower floor. It uses three helical guide rails to rotate the car 171 degrees, moving it from one level to the next.
It is the first passenger elevator in the world to rotate on helical guides and is believed to be the tallest free-standing, glass elevator in the world. The elevator is constructed with chemically tempered glass from Italy.
A Closer Look: The Steve Jobs Theatre
- The theater lobby draws inspiration from the technology of glass stairs and glass facades
developed for Apple retail stores, taking it to a new level.
- It is the largest glass-supported structure in the world.
- Each 9.8-foot by 22-foot glass panel is a four-ply laminate and two inches thick.
- Sprinkler pipes, power, data, audio, and security run through conduits concealed in the 44
silicon joints between glass panels.
- The glazing features the first curved, laminated glass fittings in the world.
- The façade and roof are base-isolated from the ground and designed to withstand up to magnitude eight earthquakes.