Feature
 
 
April 2000

 


Gateway II

Making an Entrance

When height restrictions were lifted in the early 1990s, Wharf Properties was afforded the chance to maximise the development potential of its prominent Tsim Sha Tsui site. The recent completion of the Wong and Ouyang-designed Gateway II project marks the latest stage in the company's revamp of the prime property

Following completion of the first phase -- Gateway I -- in 1994, Wharf set about plans for further maximising the GFA potential of its 51,657 sq m Harbour City and Ocean Centre site. Initial plans for the development involved the creation of office and hotel towers above a new retail complex. The prospects for office developments were impressive at the time, as were those for a retail development building on Harbour City's already-strong image as a premier shopping hub.
        As construction was underway, the client presented the architects with amendments to the intitial design brief -- in the time since the project began, the market for serviced apartments had grown alongside mounting oversupply in the office sector. The development of the second Gateway phase demonstrated the adaptablity of the Hong Kong property sector as the towers steadily climbed to 32 storeys each as appropriate changes were made in the structural designs. Some office floors were changed to provide hotel and serviced apartment layouts -- office development-style columns are not suited to apartment floorplates, say the architects. The architects investigated how to change the structural design from columns to load-bearing walls and where holes needed to be punched through floor slabs for hotel and serviced apartment services. Further revisions were called for following the dip in hotel demand in the SAR during 1998 with the end result being 499 serviced apartments housed in the upper levels. At all stages of the development, the architects liaised with the contractor to implement new design solutions as both headed towards an unchanged completion date.

The exterior
The choice of name for the development reflects its significant position; standing in full view to vessels entering Victoria Harbour. To add emphasis on this entrance, and to present a bold statement of the development's location, a distinctive stone-clad curved archway is set between Towers Three and Five. Aside from its visual significance, the curvilinear portal houses three floors of column-free office space; two truss beams fill the equivalent space of a single floor to support the three levels above. The exterior treatment of the portal shows four floors, though the lowest level sports false windows to conceal the truss beam.
        The choice of stonework -- Azalea -- on the portal face relates across the various stages of Wharf's waterfront project. The original Gateway tower featured similar stonework of a more reddish colour, as does the new Tower Six, while the two central towers carry a more pinkish hue. The colour of stonework is echoed in the portal and, as the architects note, reflects similar hues chosen by the developer its premier developments such as Times Square in Causeway Bay. Through this, Gateway I and its new neighbours can be viewed as a cohesive development, with some stylistic variation, as well as an integral part of the developer's portfolio as a whole.
        The Gateway curtain wall comprises either double glazing or reflective glass. Double glazing had been specified for certain hotel portions of the project which later reverted to office use. The glazing's placement on the office floors offers increased energy efficiency benefits to the office tenants.
        The tower elevations draw on design cues established in the initial Gateway 1 project yet move in new directions with simple and practical design features. More visible recessing corners, or serrations, unify the new towers while each tower features curvilinear elevations. The development stands 300 metres in length and as such risked becoming a single, straight facade or a wall pressed against the waterfront. The curved elevations break this visual impact and clearly present the individual building forms to viewers. At roof level, the presentation is flat; on the level set by the first towers. The architects note that as the majority of projects in the Tsim Sha Tsui area use flat roofs, the rooftop treatment fits into the local built environment. Despite restriction at the site dictating the height of Gateway I and the subsequent towers, a maximum number of floors has been incorporated into the development. A post-tensioned flat-slab flooring system, with drop panels around column heads to take up loads, is used to ensure clearances for ceiling E&M services. Further services are routed through floor trunking and conduits.

Courtyard entries
The main entrances to the mall and the development above are placed between the existing buildings lining the harbour side of Canton Road. Pedestrians enter through courtyards signposted by festive, brightly-coloured cladding at the streetfront. Facades lining the courtyards are upgraded in the pinkish hues of the towers' stone finishes, applied here as stonework and spray coating. Eateries are on hand to add a more refreshing ambience. On the ground is a mosaic of granite tiles, arranged in marine-inspired patterns to denote the identity of Harbour City. According to the architects, the entries serve as quiet buffers from the busy western Tsim Sha Tsui streetscape.
        Pedestrians travel up a flight of steps out of each courtyard and into the mall. Entrances to the offices, via escalators, are aligned with the courtyard entry points to give as straight a line of travel as possible. The escalators lead up to the third floor lobbies designated for the towers -- the mixed uses of the development are segregated accordingly. Separate entrances are provided for the serviced apartments while office floor elevators will not stop on the serviced apartment floors and vice versa.

The shopping street
The Harbour City shopping mall has, over the course of its existence, served as a de facto covered walkway stretching along Canton Road. The architects noted that pedestrians entering the mall at the Peking and Haiphong Road junctions, previously chose the air-conditioned route through the mall's tight and winding corridors along to Ocean Terminal and the Star Ferry Piers. The redevelopment provided an opportunity to build on, and improve, this circulation. The straightforward solution is that the new first and second floor retail areas are arranged in a straight line -- the pedestrians' lines of sight cover the length of the development. Lofty atriums are installed as punctuation along the mall's length. With the help of the open spaces, arriving visitors can immediately identify their location within the mall before heading off to their destinations. The arrangement has proven successful, say the architects, and the end result has been the formation of a new shopping street for the Tsim Sha Tsui area.
        Ceiling heights within the retail area were dictated by the clearances in the existing retail areas to which it is joined. The possibility of raising the ceiling height in the new mall proved unfeasible -- the necessary stairs and ramps to accomodate the floor level diferences would have been a less-than-favourable arrangement for shoppers. Despite the headroom being slightly lower relative to other retail developments in the SAR, a sensation of space and headroom is provided with the placement of atria with vertical transport placed within.

Construction challenges
Development of Gateway II called for the demolition of three residential blocks and the portion of shopping mall beneath, creating multiple challenges in the project's realisation. The podium and basement structures were structurally connected, posing challenges in not disturbing the remaining mall and buildings during the demolition process and the subsequent interfacing with these structures as the new project went up.
        The Harbour City complex was relying on a central building services system -- in particular the ventilation system as well as the electricity supply. The architects, contractor and consultants liaised to ensure sufficient services were uninterupted as the contract proceeded. A services diversion ensured that the sea water pump house for the water-cooled air-conditioning system remained connected to the buildings on the opposite side of the site. This was another project in itself, say the architects.
        Demolition of the existing buildings posed the difficulty of countering the uplifting effect as the dismantled structures became lighter and lighter. The solution was appropriate backfilling of the basement with demolition debris to ensure a constant loading to overcome the uplift. Interfacing the new and existing basement was similarly challenging in adhering to fire safety regulations and supressing water pressure against the site. Where the two basement structures would break through, a temporary wall and fire shutters were installed. Emergency exit stairs and escape routes were also designed for the vertical discharge needs of surrounding blocks and hotels during the construction period.

Traffic concerns
One condition of development for Gateway II was implementing traffic control measures. With the completed project bound to increase the number of vehicles coming into the Canton Road area and surrounding streets, the waterfront strip in front of the development was earmarked for traffic. Incoming traffic to Gateway II and Ocean Terminal is directed along the harbourside. A new circular ramp acts as an exit from the Ocean Terminal carpark to reduce the traffic load at Canton Road. In the time since Gateway II's completion in late 1999, the arrangement, combined with a nearby flyover, has proved a success in alleviating the traffic jams that once plagued the area.

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FAST FACTS
  • Total GFA ...........................................
  • Building height ......................................
  • Demolition ...........................................
  • Completion ..........................................
242,156 sq m
128.9 mpd
January 1994
October 1999

developer Wharf Properties Ltd
architect Wong & Ouyang (HK) Ltd
consulting engineers Wong & Ouyang (Civil-Structural Engineering) Ltd
                             Wong & Ouyang (Building Services) Ltd
main contractor Chevalier Construction (HK) Ltd


-- Building Journal