April 2000


Kwai Tsing Theatre

Theatre without compromise

The development of Kwai Tsing Theatre marks the first step towards providing new performance venues for the New Terittories population. Local residents' exposure to the performing arts has previously been limited by distance and a lack of adequate venues -- patrons have traditionally travelled to the Cultural Centre in Tsim Sha Tsui, or further still to Hong Kong side, to catch large-scale theatre and concert performances. With the smaller existing multi-purpose venues at Shatin and Tsuen Wan Town Halls becoming outdated amid the rapid advancement of stage technologies, the former Provisional Regional Council and Regional Services Department -- now the Leisure and Cultural Services Department -- selected three sites for new specific-use venues. Designed primarily for theatre, Kwai Tsing is the first of the three projects to be implemented. The facility is conveniently located opposite an MTR station and provides a fully-equipped theatre venue for residents in the Kwai Chung and Tsing Yi areas

Design of the project commenced in 1991 and progressed for three years until problems arose when the West Rail project was made known -- the railway line was set to pass through the site. Subsequent changes to the railway alignment -- shifting the tracks to underneath the adjacent Kwai Fuk Road -- helped alleviate difficulties but only to a certain extent. "Because of the railway, we needed to change the orientation of the building," explained Senior Architect Benny Chan of the Architectural Services Department (ArchSD). "We needed to move the building as far as possible from the railway, which meant that we had to redesign the whole building." In addition, a building isolation system was specified to create a buffer from vibrations coming from the railway line.
        An acoustic consultant was employed to study the effects of the railway and a building isolation system was deemed necessary -- physical and sound vibration had to be limited to levels which wouldn't disturb theatre patrons. "The isolation system suspends the whole building from the ground on heavy-duty springs," said Chan. Around 320 spring units support the auditorium seating area, main stage, side stages and rear stage to hold these sensitive areas above the ground surface.
        Housed in a cavernous undercroft below grade, clusters of steel spring units isolate the selected areas from railway vibrations. For the substructure, piles with a minimum width of 900 mm are socketed into the granite bedrock. The pilecaps rise clear from the ground in the undercroft void with the steel spring units mounted on top to support the 29,500-tonne dead load. Designed to isolate the auditorium and stages from a vibration source of a 3.5 Herz natural frequency, the spring units have a 20 mm vertical deflection under the dead load and a 1,800-tonne design operating live load. Above the springs, the superstructure sits on pad foundations. Stability for the superstructure -- chiefly comprising reinforced concrete except for the steel auditorium roof trusses and flytower motor room trusses -- comes from shear walls on the perimeter.
        Due to the expense of the system, this suspension is not applied to the entire theatre building. The portion supported on the isolation system is separated from the non-isolated remainder of the building by what the architects term as the railway vibration joint. A look at the architectural drawings offers a clearer examination of the joint; its alignment marked on plan by sets of columns placed on either side of the separation. The joint is fire- and noise-resistant and its provision added to the complexity in construction, said Chan.
        With the location and isolation system decided on, the organic shape of the structure was designed to provide a dynamic feeling for the building, say the architects. The curves flowing around the perimeter add contrast to the rectilinear fly tower structure rising from the centre. "For the main part of the theatre we have the fly tower and backstage areas which functonally are a rectangular form. But outside we wanted to add a curved and circular form to make a contrast on the building," explained ArchSD Architect Jane Au-Yeung.
        The exterior focal point is the entrance, marked by a glazed, circular lobby area with a transparent tensile canopy structure in front. Explained Chan: "One of our design themes was to make the foyer as transparent as possible because the other part of the building is comparably solid, so we tried to make a contrast here." In addition, the foyer being completely transparent means that visitors will see it as the focus of the building and head towards it directly. The effect is heightened in the evening -- when most of the productions will be held -- as the light coming from within the lobby will act as a beacon.
        The entrance canopy serves not only to help signify the entrance and provide shelter from the rain but allows people in the foyer to see straight out into the plaza through the clear glass panels. Untinted glass was chosen for the glass wall and canopy and the lamination was selected to filter ultra-violet and infra-red light.

A calm atmosphere in the spacious foyer is developed through the use of warm tones of browns, greens and deep reds on a beige base colour, the architects said. The colours are applied in stone and reconstituted granite throughout the sunlit lobby area which boasts circular forms to echo the exterior design. The focal point of the lobby is a circular skylight in the centre of the ceiling. The cylindrical void is surrounded by a circular pattern which is followed in the floor pattern below.
        "The whole design concept is centred around the interaction between the performers and the audience," explained Chan. "This theatre is quite different from similar venues in Hong Kong. When the performers want to go to the dressing rooms before the performance, they don't need to go through a rear door; they enter straight through the foyer." The same goes for leaving the venue, post-performance, when they can meet with patrons still milling about the lobby. The foyer also holds enough open space for small-scale informal performances and contains room for floor displays and exhibition panels. Provisions on the ceiling allow for hanging display materials as well.
        At the ground floor level, visitors can head to the right of the central staircase and Urbtix counter to arrive at a 120-seat lecture room, or they can walk to the main auditorium entrance on the left. Patrons seated in the downstairs section of the auditorium move to the second part of the foyer, which radiates on plan from a curved wall. Unlike most theatre designs, the Kwai Tsing arrangement sees all theatregoers enter the auditorium from one side. For the downstairs seating, entrances are provided at the front and rear of the same side. Patrons seated in the balcony walk up one floor to another foyer and entrance, also on the lobby side of the hall.
        The upper level also houses an exhibition gallery, a dance studio, a rehearsal room and the theatre offices. Oriented adjacent to extensive glazing so that it can be viewed by people entering the theatre, the exhibition hall will be used for smaller theatrical or community events. The large, rectangular hall features theatrical parcans and spotlights pointing towards the high false ceiling while lighting tracks beneath are provided to hold spotlights in place for exhibitions. Speaking as the gallery was being prepared for a storytelling event, Leisure and Cultural Services Department Technical Director Mark Taylor explained: "Using the venue for this kind of performance is one of the ways to stretch its use and we have ideas in the coming years to make this into a more formal space. We will put in some form of theatrical lighting suspension within the ceiling grid, or above the grid, so that we can have the best of both worlds."
        The two large dance and rehearsal rooms on the same level were specified from the start of the project, said Senior Cultural Services Manager (Kwai Tsing Theatre) Mandy Tong. "At the beginning of the project we drew up a schedule of accomodation to specify future uses. For the dance studio, we specified that the room should be suitable for training classes and also dance practice," she said. Both rooms feature floating floors -- on top of the concrete structure rests another slab on springs so that the entire maple floor is isolated from the structure. The sprung floor prevents the sound of the dancers transmitting through to the main auditorium and lecture theatre. Both square rooms feature sound insulating surfaces on two walls and mirrors on the other two, and both have high ceilings. As Taylor explained, the height gives performers the confidence to leap and move freely, especially when rehearsing traditional Chinese opera and dance routines featuring swinging sticks and weaponry. Each studio features a different lighting pattern -- a radial arrangement in the dance studio and a diagonal arrangement in the rehearsal room -- which adds visual identities for each of the otherwise similar spaces.

The main attraction
"Theatre is the dominant artform that this theatre has been designed for, without compromise," explained Taylor, "whereas Yuen Long Theatre, which will open towards the end of the year, has been designed more as a music space with a more reverberent hall." The auditorium offers an intimate setting for 900 patrons -- an ideal capacity for drama. As Chan explained, if the hall is too large, the interaction between the performers and audience will suffer." In modern-day drama performance, you need to take care of the interaction between the performers and the audience. If the audience is too far away, or the size of the audience is too big, we won't have good intimacy.
        "A criteria for theatre is that the audience should not be too far away from the stage because when you see a performance you need to see the facial expressions of the performers and also some of the minor body gestures," Chan added. Accordingly, the seating area stretches back to an actual distance of 25 metres. In order to do this, the auditorium was planned in a fan shape so that it radiates away from the stage, meaning that the side walls have an inclined orientation to the stage. A Continental seating arrangement was selected within the fan-shaped hall -- an arrangement that has no intersecting aisles in any row. "That means you get enormously long rows," said Taylor. "You must have correspondingly good pitch between rows so that you can have easy access. This, in turn, gives a comfortable amount of leg room. There are no good seats lost in this venue. Traditionally you would have an aisle down the middle yet these are the best seats. They split the audience up; for the performer it puts up a visual divide."
        The shape of the hall posed initial limitations on sound quality, said Chan. "If you want good acoustics you need some early reflections from the side walls, which means ideally you should put the side walls parallel." As a result, and to heighten the sound experience for non-theatrical presentations, an electronic reverberation system was incorporated. The system consists of microphones hanging above the front of the stage to collect a signal which is then sent into a computer for processing. The sound is then projected back to the audience through speakers placed throughout the seating area. The signal is processed to create set levels of delay, so the audience will sense a reverberation in the hall. Acoustic reverberation requirements range from 1 second for speech and drama to as much as 2.5 seconds for symphonic presentations. As such, a compromise of a 1.5 second reverberation time would be less than ideal for either, said Chan.
        "Because of the drama use, there are some very specific requirements. The major concern is the clarity of the hall -- when the actors speak on the stage they must be very clear to the audience. That means the reverberation time must not be too long, so we designed the hall to this end for a reverberation time of about one second. That means we need to limit the volume of the audiorium. But in turn, for concert or opera performances, it could not be very good in terms of acoustics. So we built in an electronic reverberation system in the hall to provide some artificial reverberation so that when the theatre is needed for a music performance, they can switch on the electronic system to provide the necessary artificial reverberation. This is the first hall in Hong Kong that was built with such a system at the beginning." A similar system was retrofitted at Shatin Town Hall.
        For concert performances, an orchestra shell is placed around and above the stage as an added acoustic enhancement. The orchestra shell is formed by about-ten-metre-high towers with a ceiling panel suspended above. Each of the vertical side panels weighs as much as two tonnes, explained Taylor, and each is moved on compressed air castors. The ten-tonne ceiling panel, when not in use, is tucked into place vertically above the bridge -- the movable horizontal top edge of the proscenium, or stage opening. Taylor: "With the bridge being on screw jacks from its ends with no cables in between, that means you can utilise that space above. This is enormously effective for us because if you had that huge peice just hanging somewhere in the middle of the stage it makes a mockery of having a flexible venue space." To deploy the panel, the shell roof is lowered vertically down to the stage, where it contacts onto wheels and angles backwards before rear drop hoists are connected to it. Once the interlocks are working, the panel picks itself up and, when horizontal, extends itself under the gap in the bridge and up to the safety curtain to create a complete acoustic seal.
        When the vertical side panels are not in use, they are stored in the side stages. "This is the first venue where we have full-size side stages and a rear stage," explained Taylor. The Cultural Centre, on the other hand, has a rear stage and a truncated side stage. The rear stage features a motorised wagon with a revolving stage on which a complicated set can be built to be brought out to the main stage during a performance. The side stages can take less-complicated sets which can be moved manually, while trapdoors are provided within the main stage.
        High above the main stage sits the grid level supporting the hoisting equipment for individual items and backdrops. Hoists for the horizontal fly bars that can be raised or lowered are housed in the top level with cables passing through first the metal grid and then acoustic traps before reaching the dust-free machine room. All hoists and stage equipment are controlled from a computer console located halfway up the eight-storey tower, assigning pre-programmed or individual commands to the stage machinery.
        In front of the stage, an orchestra pit can replace the first three rows of seating during opera or ballet performances. As Taylor explained, the presence of the undercroft meant that conventional mechanisms for lifting the platform requiring caissons were ruled out. "The orchestra lift also uses technology that is brand new to Hong Kong; Spiralift technology. It can move a lift up and down by 30 feet but the mechanism only requires a magazine space of about 60 centimetres high. It takes a vertical band, a horizontal band and feeds them both out at the same time to create an absolutely taut column that zips itself together, and unzips itself as it comes back down." The system can rise as far as the length of the vertical band allows and positioning is provided by a built-in brake on the cylindrical rotor. At Kwai Tsing, three floor-level units are syncronised to raise and lower the orchestra platform as necessary.

Leisure and Cultural Services Department

architect, project manager and building services engineer
Architectural Services Department

main contractor
China International Water & Electric Corporation

structural engineer
Ove Arup & Partners HK Ltd

quantity surveyor
DG Jones & Partners (HK) Ltd

stage engineering and stage lighting consultant
Technical Planning International in association with Gregory Asia

nominate sub-contractor for stage machinery and lighting
Strand Lighting Asia Ltd

-- Building Journal