Tall Buildings  

The Henderson  |  Hong Kong  |  Zaha Hadid Architects

Heart of Glass

A bulbous building sprouts in Hong Kong’s central business district, pushing the limits of curved glazing

By Andrew Ayers

Photo © Virgile Simon Bertrand

The Henderson. 

Standing out from the crowd is all about the company you keep. If your immediate neighbors are generic housing towers, attracting attention is easy in Hong Kong. But when you’re located between Central and Admiralty, with I.M. Pei’s twistingly tri­angulated Bank of China and Paul Rudolph’s “look-at-me!” Lippo Centre right next door, not to mention Foster + Partners’ fabled HSBC headquarters just opposite, the competition is far more daunting. This was the challenge facing developer Henderson Land, which in 2017 paid an eye-watering $3 billion for a 31,000-
square-foot plot on Murray Road, next to Chater Garden, a public park. Seeking to wow the rental market, Henderson sought office-tower designs from a handful of globally acclaimed firms, choosing London-based Zaha Hadid Architects (ZHA) over names such as Foster and MAD.

Photo © Virgile Simon Bertrand

Rising adjacent to the Bank of China tower, the Henderson cinches inward to shape a lobby.

“The client made it very clear they wanted to maximize the views,” says Sara Klomps, ZHA’s lead architect on the project. “Unless you’re on the waterfront, you don’t get panoramic vistas like this in Hong Kong. So it was a given that we had to design a tower in glass.” Henderson also wanted the 36-story, 650-foot-tall building to be “as clean as possible,” to exhibit “soft forms,” and to offer unencumbered floor plates, which meant pushing the elevator core to one side. “We also felt it was wrong for the tower to act as a barrier on meeting the ground,” continues Klomps, “which is why we lifted it up, to afford views through the greenery and allow Hong Kong’s aerial walkway system to connect up underneath.” The building also includes five levels of underground parking, which replace the garage that formerly stood on the site, and a glass-roofed lounge, known as Cloud 39, at its summit.

Formally, says Klomps, the tower is “a very intuitive response to the Bank of China,” which rises to a rather staccato beat. At the Henderson, this translates into asymmetrical bulges in its glass facade, which are organized around two “pinch points,” as Klomps describes them, each located above one of the two giant trusses that compensate for the displacement of the elevator core. Though this aspect of the building’s structure is not expressed externally, its presence can be glimpsed through the air vents that ring the tower at these levels: the upper band corresponds to an outdoor refuge floor, as required by Hong Kong’s construction code, and the lower to a technical area (no machinery could go on the roof because of the lounge). Columns, which line the perimeter, are a composite of steel and concrete, while the floor beams are in steel with a composite deck.

“The Henderson was made at a moment when the technology was available to do it,” says Klomps of the digital bending ovens that shaped the many panes of curved glass used in the tower’s facade. But she is keen to point out that the building isn’t as extravagantly shaped as it might appear. “We went through a long rationalization phase to get the curvature to a reasonable amount. In the end, only 20 percent is double curved: there’s a fair amount of flat glass, and a fair number of single-curve panes. There’s nothing crazy.” What was probably novel, she concedes, was using so many curved pieces on a building of this scale, which posed a manufacturing challenge for the European firms that won the bid (locals proved too expensive), given the rapid construction timetable. While the majority of the facade comprises factory-preassembled units, which allow for quicker on-site construction, the “belly,” where the glass curls under at the base, was built the old-fashioned way, its components assembled in situ. 

Torre Unipol  |  Milan  |  Mario Cucinella Architects

Go With the Flow

To save energy and enhance thermal comfort, Milan’s latest tower emulates nature

By Leopoldo Villardi

Photo © Duccio Malagamba

Torre Unipol.

Milan may be known for many things—fashion, design, art. Riveting skyscrapers, on the other hand, have been few and far between since 1958, when Gio Ponti’s Pirelli Tower and BBPR’s Torre Velasca first soared into existence.

Mario Cucinella’s 24-story Torre Unipol, a new corporate outpost for the eponymous Italian insurance company headquartered in Bologna, is a rare and welcome addition to the Lombard skyline. The chrysalis-like structure, jacketed in a distinctive tessellated facade, rises from a prominent corner plot in Porta Nuova, one of the city’s two recently developed financial districts. Unipol Group’s 2014 merger with Premafin-Fondiaria-Sai came with the prized parcel—at the time, the last undeveloped one in the enclave’s master plan. Soon after, the company organized an invited competition to centralize its roughly 650-person workforce in the city. Unlike so many of Milan’s recent skyscrapers, Torre Unipol is not a speculative project relying on imported name recognition (nearby towers by César Pelli, Arata Isozaki, and Zaha Hadid all come to mind). Instead, Cucinella’s firm was selected from among a small group of Italian practitioners to design a purpose-built skyscraper—and, in this case, it is his first. 

Urbanistically, the tower negotiates the significant 21-foot height difference between the elevated Piazza Gae Aulenti and the streets below it. On the plaza side, the omission of several of the more than 2,700 flat, triangular glazed panels makes for a somewhat awkward entry. Better, and far more dramatic, is the experience entering Torre Unipol from the lower lobby along Via Melchiorre Gioia, a thoroughfare that cuts through Porta Nuova. There, a portion of the envelope delaminates from the tower’s base, curling upward to form a 65-foot-long canopy that hovers over a new plaza. Cucinella likens it to a piece of bark peeling away from a tree trunk, but, in such a cosmopolitan city, it’s difficult not to conjure a mental image of Marilyn Monroe’s iconic upswept dress in Billy Wilder’s The Seven Year Itch. The detachment also reveals a weighty azure-blue reticulated frame, fully visible inside but barely discernible through the glass (except at night), as well as a thinner structural web that together enmesh the building. 

Photos© Duccio Malagamba

A sculptural canopy announces a lower entrance (above), which leads visitors and staff to Torre Unipol’s atrium via an escalator (below). 

Photos© Duccio Malagamba

Inside, an escalator leads from a modest 35-foot-high lower lobby to a grander upper one. As visitors ascend, in a remarkable transition, the ceiling slowly creeps out of view to reveal a vertiginous, nearly 230-foot-tall atrium, lenticular in plan. Looking up, one can see the many office levels, each marked by a curved white floor plate, and the skylights overhead. Programmatically, the atrium recalls the one in Kevin Roche and John Din­ke­loo’s Ford Foundation building in Man­hattan; in scale, those wondrous spaces of John Portman–designed hotels. But here, the cavity reflects a certain organicism that pervades much of Cucinella’s work—it’s akin to a gargantuan, light-filled rib cage. Adding to the analogy, and even less obvious to visitors: the atrium is in fact a vast air pocket blown into a double-skin facade system, which wraps the rest of the tower. Above the skylights, the facade continues skyward, forming a basin like the cup of a giant pitcher plant, which collects rainwater.

The vertical chasm, facing southwest and occupying about one-third of the tower’s overall volume, not only mesmerizes—it acts as a spatial buffer. “In a skyscraper, the south facade is always a difficult one to plan,” Cuci­nella explains. “People don’t want to be near the glass, especially in winter, when the sun is low.” The physical separation from the outermost envelope helps to minimize the effects of glare in office areas, but this organization also allows the atrium to double as a solar chimney. In the winter, the unconditioned space amasses and redistributes warm air; in the summer, it exhausts heat at its apex. This strategy reduces energy use in the offices and helped the team secure a LEED Platinum rating, without sacrificing comfort. On two walkthroughs—one in the waning days of summer and most recently during Milan’s foggy winter—the atrium remained pleasant. 

Space House  |  London  |  Squire & Partners

Back to the Future

A space-age-era office building lifts off into the 21st century thanks to a sensitive refresh

By Chris Foges

Photo © Danica O. Kus

The spirit of the era is captured in the rippling cylindrical tower (below), connected by a skybridge to a sleek rectilinear block (above). 

Squire & Partners’ renovation of Richard Seifert & Part­ners’ Space House gives new luster to one of the most distinctive Modernist office buildings in central London. Stylish and energy-efficient interventions demonstrate that a sensitive approach to recent heritage can deliver what’s valued by today’s tenants, while at the same time aiding the reappraisal of the tower’s architect.

Space House was completed in 1968, amid the excitement of the United States’ Apollo program. The Swiss-born Richard Seifert and his colleague George Marsh, who is credited with responsibility for the design, channeled the futuristic spirit of the age in a form closer to the sculptural Brutalism of Bertrand Goldberg in Chicago than the utilitarian variant prevalent in Britain. A sleek, rectilinear block faces Kings­way; to the rear it is linked by a bridge to the 15-story cylindrical tower set in a piazza and perched on a ring of inclined Y-shaped piloti. Upper floors are supported by the structural facade, a lattice of gleaming white precast concrete. Each story-height component is a cruciform shape, with branches that flare outwards so the whole drum has a rippling, almost animated texture and the precision of a machine-made product. Fittingly, it was home to the Civil Aviation Authority for 44 years.

Photo © Danica O. Kus

When the developer Seaforth Land bought the building in 2018, however, it was badly worn, technically outdated, and cluttered with later accretions like partitions and bulky mechanical equipment. Squire & Partners stripped Space House to the bones and refitted it for multi-tenant occupation. The firm’s intent was to reveal the building’s obscured geometries and ensure that any additions were true to the original. But this required what project director Tim Gledstone calls “investigative archaeology.” Many original drawings had been destroyed, sending the project team to search for records in private photographic collections while looking for clues on-site like an undocumented staircase rising from the foyer.

Squire & Partners’ most significant alteration remedies a defect born of use. Bulky air-conditioning equipment that accumulated on the roof has been replaced by two additional stories, reinstating the crisp silhouette that Seifert intended. As the building is now protected, the extension required careful negotiation with heritage authorities. 

The new 16th floor is faced in an extra ring of color-matched concrete cruciforms. Looking up, the surgery is imperceptible. To avoid an unsightly elevator overrun, terrazzo stairs complete the journey to the new 17th story, a glass-walled aerie encircled by a terrace. Air-source heat pumps are discreetly concealed above. 

The Eight  |  Bellevue, Washington  |  Pickard Chilton 

Putting Down Roots  

A Pacific Northwest tech hub’s newest downtown office tower prioritizes public space, inside and out

By Rachel Gallaher

Photo © Erik Stackpole Undehn

The Eight welcomes visitors through a soaring lobby with a custom chandelier by Warbach. 

THE FIRST TIME that architect Anthony Markese visited the Bellevue, Washington, location for the Eight—a 25-story, mixed-use office tower commissioned by Skanska Commercial Development—it wasn’t the project site that caught his eye, but a towering redwood tree on the corner, two blocks to the west. An unusually tall specimen for the downtown core, the conifer seemed left over from a time before high-rises dotted the Seattle metro area’s third-largest city, located on the shores of Lake Washington.

“I feel as if that tree has been here for 40 years, and it has just survived the urban environment,” says Markese, a principal at New Haven, Connecticut–based firm Pickard Chilton Architects. “To us, that was a majestic tree, and, in a way, it became a metaphor for the building.” 

Located on one of the city’s main thoroughfares, the project stands out from the surrounding office buildings, which have sprung up rapidly over the past two decades as Bellevue’s downtown has evolved into a tech hub. While most developments in the area are some form of a rectangular box, the Eight is a head-turner due to its unique oblong shape, visible structural elements, and ample communal space apparent across a large landscaped plaza.

Photo © David Sundberg /  Esto

The Eight towers above a lone redwood. 

“Skanska was very forward-looking when [we] started to propose the many outdoor spaces, and [they] embraced the street and being connected with downtown,” Markese says. In addition to being the client, Skanska was the general contractor for the project—a unique position that, according to Markese, resulted in the company’s openness to creative and out-of-the-box solutions. “Not many owners we work with are willing to take on so much exterior space,” he says.

Before demolition, the property was a forgettable blip one would drive by on the way to or from Interstate 405; it held a nondescript set of strip malls at either end of a large parking lot. “If you wanted to be in your car and pull in to grab something, it would work well,” Markese says, “but as a main location within the city, it was a little bit of a missing tooth.”

To better knit the building into the urban fabric, Pickard Chilton pushed it to the northwest side of the lot, which maximizes open street-level space. The architects also replaced the formerly steep, narrow sidewalks with wide pathways lined in native plantings. Drawing from a Pacific Northwest sensibility that embraces nature, innovation, and sustainability, the design team chose a minimal but striking palette of steel, timber, and glazing.

Fyrtornet  |  MalmÖ, Sweden  |  Wingårdhs

A New Slant

A timber building enlivens the climate-smart Hyllie district in southern Sweden

By Katharine Logan

Photo © Wingårdhs

The tower features a double-skin facade. 

In a rapidly developing area on the outskirts of the Swedish city of Malmö, just 16 miles from Scandinavia’s largest airport, a new building by Wingårdhs brings a welcome dash of verve. Fyrtornet (or “lighthouse”), as the building is called, is the first project to be completed in the Embassy of Sharing, a new mixed-use precinct within the city’s climate-smart Hyllie District. Fronting on a plaza that surrounds the district’s rail station, the 12-story mass-timber structure—tall for its type—advances what’s possible in wood construction as it enlivens its part of town.

Photo © Wingårdhs

Fyrtornet stands across the street from a public plaza. 

Architecturally, a combination of dynamic form, expressive tectonics, and vibrant color accounts for the building’s distinctive character. On two of its street-facing sides, a sloping glass envelope unifies the upper levels into a single, asymmetrical volume tilting back from the street. A deeply recessed ground floor makes for a small footprint, and timber braces touch down to support the cantilevered volume above. This creates a sheltered interstitial zone between indoors and out along both street edges, with the rhythm of the timber braces defining room-scaled bays. On perimeter beams and on the two facades that are not clad in glass, cedar shingles introduce a hand-built scale. Exterior wood is coated in the deep red of falu paint characteristic of historic Scandinavian wood buildings. It’s a playful choice for a site across from the first train stop off the Øresund Link, an approximately seven-mile-long bridge-and-tunnel connecting Sweden to Denmark and Copen­hagen Airport. “When you enter Sweden, the first thing you see is a traditional red cottage, but it’s a high-tech cottage, clad in glass,” says Joakim Lyth, architect at Wingårdhs. “It’s a funny thing, in a way.”

Photo © Wingårdhs

An overhang partially shelters the entrance. 

Targeting certification at the highest level under the Sweden Green Building Council’s environmental standard, Fyrtornet also aims to foster Hyllie’s social life. A ground-floor café and sheltered outdoor seating activate the street edge and connect the building to Station Square. On the second floor, a public library overlooks the plaza, with views between the two spaces enlivening both, especially at night, when the library is open late. Above the library, office floors step back in three-story tiers, a move aimed at minimizing shadow on the public domain. At each setback, a naturally ventilated triple-height terrace occupies the zone within the building’s double skin, and photovoltaics integrated into the exterior glass provide the terraces with dappled shade. In addition to offering a biophilic amenity for building users, the greenery intended for these intra-facade terraces will contribute to Station Square’s otherwise hard streetscape and announce, along with the timber and the solar panels, Fyrtornet’s green values. “The city really wanted these buildings to express their sustainable ambitions,” Lyth says, “so that you could actually visualize what the sustainable society of the future could look like.” 

For efficiency, the building envelope was manufactured as modular units in a tent on-site and craned into place, saving both construction time and transportation costs; joints were completed using a sky lift, eliminating the need for scaffolding. For fire protection, the building is sprinklered, and some of the falu-red paint is a fire-retardant formulation, on the shingles, for example, and on the framing that supports the glass cladding over the triple-height terraces. The timbers themselves, manufactured in Austria using European lumber, are inherently fire resistant due to their mass.

SoMA  |  New York  |  CetraRuddy Architecture

Role Model

The country’s largest office-to-residential conversion offers lessons for alleviating the housing shortage.  

By Joann Gonchar, FAIA