April 2000


Cheung Kong Center

"Prestige: respect or reputation derived from achievements, power, associations, etc."
-- The Pocket Oxford Dictionary

An intangible yet highly desirable quality, "Prestige" is avidly sought by Hong Kong building professionals as the ultimate tag for their creations. Yet, as the above definition shows, prestige is not easily acquired and simply appended -- it is the end-product of an evolutionary process. "Respect and reputation" are two qualities that Cheung Kong Holdings possesses in abundance, derived in large part from Chairman Li Ka-shing's extensive property developments (and less-heralded philanthropic work) in the HKSAR and on the mainland. Cheung Kong Center -- a 62-storey office tower -- occupies a prime site, sandwiched between Norman Foster's Hongkong Bank Building and IM Pei's Bank of China Building. When the term "Prestige" is applied to buildings, it is difficult to present a more worthy candidate

For the last four years, the Leo A Daly (LAD) team in Hong Kong has been working on a single building. Leo A Daly, the third largest architecture/engineering firm in the US, served as Prime Architect for Cheung Kong Center (CKC). The global design team united several prominent firms: design consultants Cesar Pelli & Associates, structural engineers Ove Arup & Partners, landscape consultants Belt Collins, lighting designers HM Brandston & Partners, and engineers Flack & Kurtz and Parsons Brinckerhoff & Associates.
         CKC's location -- between the Bank of China and HSBC towers -- is one of the more conspicuous sites in Central. The Hong Kong Hilton used to be here, but the desire for a flagship office tower in this precise location superseded even the need for a five-star hotel. Although Cheung Kong -- in collaboration with the Land Development Corporation - was already involved in developing The Center further west, the site was just too good to ignore. The Hilton was razed in 1995 and plans to erect an office tower were mooted.
         The height for the new tower was specified at 290 metres to keep with the glide plane between the Bank of China and HSBC towers. LAD's design philosophy for Cheung Kong Center grew out of the idea of taking the old Hilton hotel site and amalgamating it with Beaconsfield House and the carpark behind. LAD worked closely with Pelli to design the unique curtain wall and to determine the tower's architectural relationship with the Bank of China and the Hong Kong Shanghai Bank towers. The Daly team also designed the tower's glass and stainless steel base, its lobby and public interiors, and the pedestrian-friendly urban landscape linking it with its neighbours, among them some of Hong Kong's most historic public buildings and grounds. Three key design issues informed their vision: the maximisation of available square footage on each floor, the appearance of the tower's simple, classic form in a complex context, and the character and connectivity of the important public spaces at the tower's base.

An oasis with facilities
Around the base, stepped gardens form a man-made expression of the powerful slope of the Peak, which comes to level-grade at Queen's Road. Crafted in stone, water, and exotic plantings, the gardens recall Hong Kong's harbor and verdant natural palette -- a shimmering, tropical environment complementary to the reflective glass and luminous stainless-steel skin of the tower.

         LAD's site planning needed to integrate a number of facilities on the site -- for example, a public toilet and a post office. How to integrate and implement these facilities with the design as a whole represented another challenge for the design team.
         At the tower's base, over two acres of public space include the lobby, gardens, a post office, public restrooms, and circulation for both cars and pedestrians. The tower's landscape also provides cross-site access to many neighbouring destinations, politely offering the citizens of Hong Kong pathways rather than obstacles. Ray Zee -- Design Director on the project since its inception four years ago -- credits this civic-minded foresight to Cheung Kong's long standing in the community: "I think that Cheung Kong as a group wanted to give something back to the city, on this site with so much potential. They could have put up a 'concrete jungle' but they didn't -- they took the time to consult with us and the landscape architect.
         "We located the new carpark under the ground in order to create a park landscape with water features and lots of greenery. Cheung Kong Center can be considered an oasis in Central."

Situating the tower
Given the prominence of the site, it was clear that the design team would exercise great care in placement of the structure. The project had to respond to the neighbouring buildings -- the aforementioned Bank of China and HSBC towers, St John's Cathedral, the former French Mission (now the Court of Final Appeal) and Citibank Plaza. As LAD didn't want to create any settling problems, they had Ove Arup Geotechnical oversee the project to ensure that what had been constructed in the 19th century wouldn't be disturbed. The final placement is the result of first respecting the surroundings, then creating the right orientation and siting so that everything was complementary.

         The LAD team eschewed the typical "harbour view/mountain view" scenario. CKC is sited to present two views toward the harbour, one spectacular view looking up towards The Peak and another view facing Western. The siting takes better advantage of the views than a typical north/south orientation.
         The resultant tower is resolutely square -- an unblemished rectangular pillar. Not only does it hark back to more traditional architectural forms, but it contrasts with its (far) more angular neighbours. The square plan represents the most efficient use of space. The client wanted a timeless and elegant building, with a simple shape which dovetails into curtain wall.

The curtain wall and the grid
Cheung Kong Center's curtain wall scheme is highly specific. From afar, the building appears seamless, but as you approach, you discover that detail is added through a system of grids. The curtain wall is based on a 7.2-metre grid which breaks down into a sub-grid which is highlighted by fibre optics at night, adding a level of detail and sophistication as you get closer to the wall.

Steel as a fabric
The curtain wall is executed in 'linen steel" which was also used on London's Canary Wharf project and KL's Petronas Towers. This cladding has a chatoyant quality -- when lit by the sun, it gives off a glow which serves as a highlight for the curtain wall. Many of the cladding members are curved, allowing the curtain wall to 'track' the sun as it passes, giving highlights to the building during the daytime.

         A new material, linen steel is only one component of the sophisticated curtain wall system. The system is able to withstand severe wind-loads of minus-seven kPa. At the base, high-performance glazing from Viracon is used. The glass panels (custom-made due to their large sizes) provide up to 100 per cent light transmittance but block out 75 per cent of the UV light, permitting clear vistas up Queen's Road or up Chater Garden without admitting a great amount of heat. In addition to the UV-screening benefits, the glazing insulates sound as well; at the lower floors, street noise is barely audible.

The glass core
The steel-and-glass enclosure showcases a spectacularly illuminated interior-core wall. The LAD design team went through at least twenty different suppliers while searching for the right glass to execute this design vision. Their 'glass core' concept is intended to bring elegance and simplicity to Cheung Kong Center, as well as a sense of the future. The concept contributes to Cheung Kong Center's balance of ethereality and substance. The design team wanted the core to read as a glass structure -- rather than a bulky core, an all-glass encased skin core without frames was used.

         The entire building acts as a tool to make the glass brighter, which means that the composition of the glass was critical. Two types of glass were used, one with a sea-shell pattern, highlighted with dichroic glass -- a treated, coated piece of glass which keys on the spectrum of available light. The latter enhances the light play of the structure -- from one end of the building to the other, you see reflected light ranging from the blue spectrum to the red spectrum.

Fibres and floods
Cheung Kong Center softly glows in the night hours, presenting a unique addition to its particular patch of the world-famous Hong Kong skyline. To accomplish this, fibre-optic lighting was employed. This scheme not only provides very even lighting but makes it easy to change the overall lighting scheme; by simply changing the bulb in the ceiling, a new lit facade is easily achieved. Fibre-optic lighting is nothing new in the world of hi-tech or telecoms but is a new and welcome trend in terms of building decoration.

         In addition to the fibre-optics, the exterior lighting system uses a series of floodlight scoops that are aimed upward. The floods bathe the building in a white light at nighttime and are used in unison with a fibre-optic system that has colour-changing capability, but for the most part will remain white-on-white. The floodlights are for closer views, the fibre optics for long distance views. As you get further and further away from Central, the fibre-optics are what make the building 'read', rather than the floodlights.
         A beatific lighting touch known as a 'halo' was added by the design team. At the very top of the tower, to complement the lighting at the base (a backlit core), and the curtain wall (an exterior lit core), there is a 'halo' This halo effect is achieved by shooting special studio lights across the underside of the roof. A curved panel surrounds the top of the tower and caps off the building.

The lobby
At 16 metres high -- the equivalent of four stories -- the main lobby invites pedestrians into the building. The vertical thrust of this lobby gives an impression of reaching for the stars, and the lighting accents above the lifts (triple translucent extended ovals that fire up with a yellow glow to announce lift arrival) lend a classy sci-fi look (think Forbidden Planet rather than Bladerunner). These accents are echoed in the upper ground floor lift lobby, which is accessed by escalator or staircase.

Building services
Cheung Kong Center offers 53 office floors with a total GFA of 102,190 sq m. The column-free floorplates average 1,720 sq m.

         Cheung Kong Center's building services reflect the superb quality of the building. The building is equipped with a Totally Adaptive Air-conditioning System (TAAS) -- the entire raised floor is an air-conditioned plenum. Individual FTPUs (Fan Powered Terminal Units) are variable air volume control devices which mix cold air from the plenum with return air from the office. The FTPUs can be individually controlled to suit personal requirements and allow maximum flexibility. Perimeter FTPUs are also equipped with electric heaters. When offices need restructuring, TAAS affords a high degree of flexibility to modify internal layouts, accommodate organisational changes and expand technological requirements at low cost with little time or effort.
         A total of 28 passenger lifts serve the building from the ground floor lobby and the upper ground floor lobby. At nine metres per second, LAD says that these are the fastest elevators in Hong Kong. The passenger lifts provide news and information via in-car LCD screens, and two service lifts serve all floors from the basement loading area.

A long term view
Zee has nothing but praise for his client's foresight on the project. "Cheung Kong and Hutchison have taken a proactive long term view with this project. They put up what I consider an outstanding flagship building and they have really thought of everything. For example, in terms of building maintenance, the client has thought of what's going to be needed for the first few decades of the new millennium.

         "An architectural project of this calibre doesn't come along very often. And you certainly don't want to be testing ideas on such an important site. Cheung Kong and Hutchison allowed us the time to really study the site, which allowed us the time to come up with the right solution and set up what was right for the program.
         "On a side note, the most enjoyable aspect of this project is the people involved on the project, especially the people on site. It hasn't been a typical project where people complain about how they cannot do something. Everyone that's been on site has had the attitude of 'Let's all help to realise this vision? Everyone's been more than helpful, meeting you more than halfway, and I think everyone involved is proud to have worked on this building."

For more information on Cheung Kong Center, http://www.cheungkongcenter.com is where to point your browser.

developer Hutchison Whampoa Property Group
prime architect Leo A Daly
design architects Leo A Daly with Cesar Pelli Associates
main contractor Paul Y. - Downer Venture
m&e Flack & Kurtz/Parsons Brinckerhoff
curtain wall Permasteelisa
lighting designer HM Brandston & Partners
quantity surveyor Levett & Bailey Chartered Quantity Surveyors Ltd
lifts & escalators Ryoden Lift and Escalator Co Ltd
fire services Guardian Fire Engineers and Consultants Ltd
landscape architect Belt Collins Hong Kong Ltd

-- Building Journal