A new office concept with highly transparent atria
UBER is building its new corporate headquarters in a centrally located district of San Francisco. The two buildings, 55 and 33 meters high, will be clad with highly transparent exterior and interior façades. They are connected by two two-story high glass and steel bridges. The numerous atria in front of the offices are naturally ventilated via innovative bi-folding windows which have been developed specifically for this project. Computers control the opening and closing of the 4.4 m high and 3 m wide windows in the glass facade.
Cover image: (c) David Eichler
UBER has built a 12-story and a 7-story glass building on a 39,300 square meter site in Mission Bay. A number of uniquely glazed atria facing Third Street can be ventilated via motorized double-folding windows that blend harmoniously into the facade grid, thereby significantly reducing the need for mechanical ventilation. Upon completion, around 3,000 employees will move into the building complex. The installation of the façade will be completed by the end of 2020.
Highly transparent façades make the movements inside visible
ShoP Architects in New York designed two highly transparent and open buildings that aim to reflect the corporate culture of UBER. “There is a transparency we have internally where anybody can talk to anybody about what is going on,” says Adony Beniares, manager at UBER Technologies Inc. While many technology companies are building their campuses far away from the city center, UBER wants to use the new building complex to revitalize the central district near the basketball stadium. The buildings will feature retail spaces at ground level.
Furthermore, a new office concept aims to foster communication. In contrast to completely open office spaces, the architects have arranged the offices in a series of smaller neighborhoods. From these offices, employees have access to shared space zones with functional and meeting areas in the atria facing the street, the so-called “commons”. These atria extend over several floors and connect the offices with urban life. Together with the two angled, earthquake-proof glass and steel bridges, they are designed to link up with the history of the quarter as a center for shipping and trade.
The highly transparent façade, which allows views of the movements taking place inside the buildings of the mobility service provider, is divided into standard façade units of 4.4 x 3 meters (h x w), 162 of which are units with motorized opening wings. Thanks to natural ventilation and a high degree of daylight utilization, the energy-efficient building envelope makes a significant contribution to the sustainability of the buildings, which are expected to meet LEED Platinum requirements when complete.
Naturally ventilated atria via innovative bi-folding windows
Computers control the opening and closing of the 4.4 m high and 3 m wide windows in the glass facade. The two-piece windows, which were designed, engineered and built by Gartner, fold outwards to form a triangle which is open to the inside, with air flowing in from above and below. These 162 bi-folding windows make up approx. 20 percent of the highly transparent building envelope. They blend harmoniously into the breathing façade, as the size of their operable frames corresponds to the dimensions of the fixed façade units. Each window consists of two sashes, each 1.5 m wide, connected by folding hinges, with ultraclear low-iron laminated safety glass.
To ensure that the large two-piece windows open and close reliably, Gartner had to develop a new sustainable and efficient mechanism. Originally, one of the first ideas discussed with the architects was a linear actuator so that the windows open perpendicular to the surface. Since this solution would have required large forces for the opening mechanism, additional motors would have had to be installed. However, this was contradictory to the requirements of the customer, who was primarily focusing on appearance and performance.
New kinematic concept with a sustainable and efficient opening mechanism
Load-bearing components had to be designed with sharp edges and be reduced to minimum dimensions. Instead of the intended aluminium frame, Gartner therefore suggested to use steel. Thus, cantilevered scissors and levers could be avoided. In addition, drives and actuators were to be concealed in the base frame to create homogenous views of the façade. In addition to these aesthetic requirements, the foldable windows primarily had to meet criteria of building physics such as air and water tightness, but also be able to bear wind and earthquake loads as well as provide proper thermal insulation. Further criteria for the operable windows included mobility, durability, reliability and safety.
Kinematic solutions had to take into account a rectangular frame with a central intermediate mullion and an opening area of 3 square meters. The two-piece windows were to be designed top-hung, guided by the lower crossbar. Obtrusive fittings of linear drives, for example, contradicted the required extra slim design. Chain drives, as used for sidehung windows, were also to be avoided for architectural reasons, just as extra-long connecting rods of scissors drives which were rejected for esthetical reasons.
Top-hung hinged windows with double hybrid rollers and controls integrated in the mullions
Since none of these options could fully meet the design requirements, Gartner chose to use top-hung hinged windows which are supported on newly developed double hybrid rollers. These rollers support the dead weight and enable smooth movement. Cantilevers, which bridge the distance between the rails and the hinged windows, improve the tightness through their movement path. In this way, both lateral stability and minimal material requirements of the structure could be guaranteed. A chain drive with a traction and chain pressure direction of up to 1.5 kN maximum force is concealed in the intermediate mullion. With a stroke of 900 mm, the window can be opened in a controlled manner over an area of 3 square meters.
All control units that allow mechanical synchronization are integrated in the mullion. After the closing movement of the window is finished, it is locked subsequently. Circumferential safety bars are fitted and combined in the frame to allow for emergency shutdown. Various tests, including crash tests and long-term performance tests, have proven the air and water tightness of this 750 kg structure. With regular maintenance, the motors, chains, drive systems and rollers maintained their function over a period of up to 20,000 cycles without failure.
A Group dedicated to delivering bespoke and advanced technical solutions
This project perfectly represents the philosophy of our group to use a mix of local, regional and international resources. For our worldwide activities we can rely on the capabilities and capacity of our strong network sharing the same processes and passion for the design, engineering and manufacturing of bespoke facade solutions. Of the 29,700 square meters of façades built by the Permasteelisa Group, the German façade specialist Gartner has produced 8,720 square meters, including the outer skin of the atria made of ultra-clear low-iron laminated safety glass with newly developed double-folding windows, as well as 25 operable aluminum-glass skylights with a standard size of 6 square meters and one skylight of 245 square meters. The irregularly offset façade units of the double skin façade are attached to numerous load-bearing steel columns spanning several levels. Permasteelisa’s interior façade with thermal insulation features multi-pane insulating glass with horizontal wood louvers, screens of heat-modified wood. The randomized chromatic variation derived from this treatment contributes to enriching the pattern of the panels, which are also installed on the two connecting bridge elements between the buildings.
YouTube video of the UBER façade
Watch the YouTube video below to learn more about the highly transparent UBER façades with double-folding windows:
This article was originally published in IGS Magazines Winter 2020 Issue: Read the full Magazine here for more thought-leadership from those spearheading the industry
Jürgen Wax, CEO Josef Gartner GmbH, Gundelfingen (Germany)
CEO Jürgen Wax joined Gartner in 2014 as COO and became CEO in 2016. He holds a degree in Civil Engineering from the Technical University of Applied Sciences Rosenheim, Germany and looks back on 20 years of experience in the facade industry.
Mike Kneeland, Regional CEO, Permasteelisa North America
Mike Kneeland joined Permasteelisa North America in 2001 and was promoted to Regional CEO in October of 2018. Mike has been in the curtainwall industry for 30 years.
About Josef Gartner GmbH
As a facade specialist, Josef Gartner GmbH creates engineering solutions in aluminum, steel and glass, helping the world’s best architects and aspiring builders realize their ambitious ideas.
For the past 150 years, Gartner has shaped the skyline of metropolises all over the world – from the Elbphilharmonie in Hamburg to the Academy Museum of Motion Pictures in Los Angeles, California. For large-scale and complex construction projects, Gartner is the first choice for high performance façades, characterized by innovative German engineering, technical precision, and the highest quality.
With its headquarters in Gundelfingen, Germany, the company was founded in 1868 as a family business, and in 2001 Gartner became a member of the Italian Permasteelisa Group. As part of the Permasteelisa Group, Gartner profits from a worldwide network of specialists and has a strong presence in various markets with wholly-owned subsidiaries or offices.