The Wuxi Grand Theatre was in many ways a special project for our office. It was only through our close “one-to-one” collaboration with local design institutes and especially with the client that made it possible for us to realize the majority of our design ideas and to guide the building’s design from a sketch right through to its realisation on site.
The 8 “Butterfly Wings”
The eight “Butterfly Wings” covering the opera house form the main architectural gesture of the building and as a result were one of the most demanding to realize. From the outset it was important to establish solutions for solving the difficulties associated with building and cladding mega structures with complicated curvatures, and therefore we gave a high priority to their design. Our Finnish design team developed proposals for the economic construction of the wings structure, and even in the schematic design phase drafted principle drawings for their assembly. We decided to use zinc to clad the wing’s upper surface and to use perforated aluminium to cover the lower surfaces.
Fabrication and Installation
Very early in the design process it became clear that we had to establish close ties with the manufacturers of the wings’ steel structures and cladding materials. For the steel structures we were lucky to find a local company, which was able to produce and install the thousands of double curved steel pipes required to build the wings. We insisted on developing an assembly system that would remove altogether the need for on-site welding, to reduce the risks of corrosion and to ensure the durability of the structure. Due to local customs, we had to make certain compromises which resulted in small sections of the wings being welded and painted in temporary workshops. In collaboration with the Akzo Nobel painting company we were able to regularly check the welding and painting to ensure top quality. We chose the German based company Rheinzink to supply the roofing material, with whom we produced numerous 1:1 models to solve the problems of covering the large and double curved wing surfaces.
The bottom surface of the wings proved to be the most difficult task to solve. The local company which was eventually given the responsible for the production and installation of the perforated aluminium was inexperienced. Their manufacture therefore became a learning process for us all. The main issue was finding a way to produce thousands of double curved triangular panels and to install them on site with minimal tolerance under a very tight schedule. The only way this was made possible was again through the use of several 1:1 models. Only after one complete wing was clad to test the entire arrangement we were sure that the system would work and the remaining wings could be finished.
Bamboo Wall in Main Auditorium
The reason for choosing the Chinese “wood” bamboo in the opera hall/ concert hall relates to the fact that natural wood is in general an ideal material both acoustically and atmospherically as it echoes the beauty of a wooden instrument. In addition, two strong arguments for using bamboo in particular are that it is ecologically sustainable and that it is material with a truly Chinese character.
It was required that the weight of the surface material in the main auditorium should be a minimum of 35kg/m², and that all surfaces needed to react precisely to the space’s acoustical requirements with some areas needing to be reflective and some areas diffusing. After careful study it became clear that through the use of “modern technical bamboo” this was possible to achieve. Therefore the entire interior surface of the auditorium has been clad with solid bamboo blocks which are both dense and heavy. This has not only solved the acoustic issues of the space but also our architectural aim to create a warm and intimate atmosphere for the audience with a coherent and authentic feeling by using only one uniform material.
During the design process the final type and colour of bamboo was not clear as there were many issues around the materials installation and technical performance that needed to be solved. After a great deal of study we collected various samples with different patterns and colours from several companies, and our design team in Helsinki managed to whittle down the selection to two options:
A. Classical “glue-lam” carbonized bamboo. Using the well-known natural pattern and colour of bamboo made the material’s appearance particularly authentic, and the undesirable yellow colour could be weakened with the carbonization technique.
B. Strand-woven bamboo. This is a more modern and homogenous material forming solid blocks of crushed and pressed bamboo fibres. The substantially heavier blocks also give it an acoustical advantage over classical bamboo.
The final choice between these two options came down to a technical issue, as only the strand-woven bamboo was able to obtain the required fire resistant classification. After this was established, numerous colour tests were carried out to ensure that the colour tone was right and that its distribution in the material was uniform and homogenous. Using strand-woven bamboo blocks allowed us to produce the exact dark amber colour we were looking for and to create the darker, more atmospheric space that best suits artistic performances.
Bamboo as an interior material has generally been neglected and under-estimated by architects and designers in China, one of the reasons for this might be that for centuries bamboo was regarded as a “poor man’s timber” and therefore not suitable for representative public spaces. Through its use in the Wuxi Grand Theatre we believe that we have initiated a small “Bamboo Boom” in China, reviving its aesthetical qualities, as we believe that it is in many ways the material of the future. We believe that modern computer-based design and fabrication tools can help to reconnect to and re-invent traditional Chinese wood craftsmanship.
The complex geometry and manufacturing process of the bamboo blocks were resolved using modern digital technology. Rhinoceros 3D-modelling software was used to create the required block forms, which are on average 900 mm long, 100 mm high and about 80 mm thick, and latest CNC technology was used to cut them. In total we have used about 16.000 bamboo blocks, each of which are unique and different in shape.
Strand-woven bamboo proved to be the ideal material for the fabrication and installation process. When crushing the bamboo fibres and pressing them into blocks under extremely high pressure, the bamboo loses its natural shape and becomes an entirely new material. It was crucial to have a good production partner on our side, who could assist in the necessary experiments to develop a system for the blocks production in terms of colour, uniformity, density and fire safety and to help design a unique technique for the assembly of the finished blocks on site. Incidentally the fire safety standard was met by adding a (non-toxic) fire retarder agent to the raw material during the manufacturing process.
Each block has two vertical 11 mm diameter holes cut through them into which 10mm threaded steel rods are fitted which are then attached to the secondary steel structures and the concrete structural walls. The precisely cut bamboo block arrays only allowed for a maximum of 1/2 mm installation tolerance. The naturally larger construction tolerances of the structural concrete walls were compensated by the flexible secondary steel frame structures behind the bamboo block wall. This construction system was again developed through the use of numerous 1:1 models.
During the design of the opera house we have learnt that it is possible in China to design and build details with very high international quality, but since the interior of the main auditorium was one of the most important parts of the whole building our tolerance expectations were particularly high.
Our main concern on site was the very short time left for the walls assembly after production delays with the raw material. Therefore, and since the majority of the bamboo blocks were designed with interlocking butt connections it was important for the successful installation of the wall for us to develop precise assembly instructions for the workers on site. Each block was numbered and marked in a 3D drawing for the workers to find and install correctly and quickly, all on-site manual adjustments of the blocks was strictly forbidden, and faulty blocks were to be immediately reported for reproduction to avoid time delays. A particularly high level of on-site discipline was required to follow these instructions and to produce the wall correctly.
In addition to this we instructed that the first 3 layers of blocks were very carefully installed, making sure that everything was exactly in place and level. Then since the blocks themselves can act a jig the remaining blocks could be drop into place with no significant adjustments and at high speed.
Glass Brick “Wave Wall” in the Main Auditorium Lake-Side lobby
Material and fabrication
The original material choice for the “wave wall” was red tinted ceramic tiles. Since this was not agreed by the client we proposed to use clear glass bricks instead. Early in the design process we studied together with Aalto University in Helsinki various possibilities for the fabrication by hand of the glass bricks through a series of test pieces. The choice for the final pattern and installation technique was inspired by both the work we had done for the bamboo block wall inside the Main Auditorium and by the rippling water of the WuLi Lake close-by. Later on, prior to fabrication with the Shuzhou University we developed the “wave glass brick” elements to perfection with the wave pattern being refined and the installation method being improved. Finally nearly 20000 glass bricks were produced using custom made steel moulds.
As the wave glass bricks only came in two options; 1) the complete brick and 2) ½ bricks, it was necessary to adjust the complete wall elevation including all technical installations according to the brick pattern in order to avoid inappropriate detailing. The installation principle is based on the system used for the bamboo block wall inside the auditorium. Each full glass brick has two 11mm vertical holes through which 10mm threaded steel rods are fitted and structurally attached to the secondary steel frame behind. The secondary structure is covered with a white metal sheet.
During the installation and several 1:1 mock-up inspections it became clear that it was very important to solve the lighting of the glass bricks. We opposed all suggestions to install coloured LED lighting behind the glass bricks and instead insisted on using only a white wall-washing lighting system which is installed and concealed in the ceiling above the glass brick wall.
The idea for installing a ceiling reflector in the Main Auditorium came about very early on in the design process. The architectural concept for its design grew out of the traditional chandelier in a classical opera hall in that it forms one of the auditorium’s main focal points. It was important to us to create a central art piece which would relate both to the elaborate forms of the curved auditorium walls and to the local Chinese culture which is based traditionally on symbolism and story-telling. At the same time we were seeking to install an additional lighting element which would act as a ceremonial master, guiding the audience through the performance by signalling softly opening and intermission times.
We used the references of water and the flowing shapes of the traditional Chinese opera masks as a basis for the curved stripe pattern of the parabolic shape. The reflector is formed of flowing steel stripes covered with leaf gold and is lit using special dimmable profile lighting so to create different atmospheric effects according to the audience’s schedule during a performance evening. The lighting was designed so that the figure of the Opera Mask is only visible as a thin and light weight golden surface in front of a pitch black background.
At the same time we had to meet acoustical demands of the reflector. Together with our acoustic consultants we developed the dimensions, weight and final shape of the reflector. The final image of the Opera Mask ceiling reflector became so strong and iconic that the client asked us to produce two art pieces which resemble the opera mask which were CNC cut from the same solid bamboo material used to line the auditorium. These have now been hung in the Opera House’s two main VIP reception lobbies.
The Light Columns are a design element which is aiming at linking the public context to the Theatre. The array of 50 columns starts from the main entrance square and continues through the main entrance foyer into the Wuli Lake. On the interior these columns are placed rather dense to create a forest like feeling and a human scale design element to arbitrate with the large stone volumes and gigantic wings which enshroud the space. In the daytime the colour is a pure white, and the large cellular roof windows and steel wings dominate the space, but at dusk the columns become alive and the central element of the public foyer.
The functional concept of the building layout allows for people to enter the public foyer without holding tickets for the theatres. It is intended that the general public can stroll through the cleft between the two theatres, enjoy the public interior space and possible be persuaded to visit one of the exhibitions or to buy a ticket for an evening performance. The light columns are an embodied visualization of this idea.
In the main entrance foyer the Light Columns are actual structural elements supporting the roof with an integrated drainage system for the foyer glass roof, whereas on the exterior they are providing the general lighting of the two main squares north and south of the building. The light columns are each 9,6m high and have a diameter of 75cm. The round column consist in the plan section of 4 curved and laminated glass sections with white LED lighting placed in a distance behind the surface to create an even glow. Numerous 1:1 tests and special consulting with glass experts were necessary to achieve an even curvature of the laminated glass sections, to adjust the lighting intensity and to develop the concealed fixture details.
Our idea was to create a character of the main entrance foyer which would be as close to an outdoor plaza environment as possible, and therefore provide a maximum amount of day-lighting. Also it was important for us to enable a view of the steel wings from within the space, and to create a visual split of the two main stone volumes. The solution was to engineer a roof structure consisting of a web of minimal size beam profiles which is supported by a forest of columns. The open “cells” between the structures are filled with tension wire structures and overhead glazing surfaces. As the roof is shaded for most part of the day by the main building masses and steel wings it was possible to use coated glass instead of fretting to allow for a maximum transparency.
In the daytime the visitors natural focus of the views is horizontal through the space and towards the Wuli Lake water body. At performance time in the evenings the view upwards towards the illuminated wings becomes the main attraction.
The main building material is a soft coloured limestone, and both main building bodies are cladded with this material. To create a counterpart to the glass brick “Wave Wall” in the main auditorium lake side lobby we custom designed the main stone wall in the Small Auditorium lake side lobby. The three dimensional pattern of angulated blocks relates in an abstract way to the wavy lake surface.
The stone wall pattern consist of five differently shaped stone blocks which are arranged randomly on the wall. Always one plane of the block was polished to enforce the three-dimensionality of the relief.
Black Brick Wall in the Small Auditorium
The Small Auditorium interior is made of two main materials; the strand woven solid bamboo for the balconies and the black GRG material used for the walls. The material used for the balconies is identical with the bamboo in the Main Auditorium. The black walls resemble a similar pattern as used for the stone relief in the entrance lobby to the hall. The entire wall is composed of 5 differently shaped elements. GRG (Glass Reinforced Gypsum) surfaced as the best material option as it was heavy, which suited the acoustic demands, and it was perfect for a high gloss painting which was desired by us.
We put high efforts in concealing all technical details into the walls, and so special shaped bricks had to be developed to hold the integrated surround sound speakers in the walls and to cover the rotating stage enclosure doors seamlessly. We achieved to create a neutral black wall suitable for a multifunctional “black box” theatre, but we intended to add an architectural quality to the rational space. The room interior becomes alive when the stage lighting and colours are gently reflected by the walls during the performance.
The ceilings of the public lake side lobbies are custom designed by us to conceal all technical equipment and to provide for the necessary acoustical absorption surface. We decided to use hexagonal elements made of white GRG material. The hexagonal shape enabled us to develop a seamless pattern of circles which can host the lighting, sprinkler and air conditioning fixtures. Depending on the height of the room these elements have two different sizes.
The ceiling pattern is only broken by the large scale round roof windows which supply framed views to the steel wings above. These round openings are lined with white corian material with integrated LED lighting dots to resemble a modern version of the classical opera lobby chandelier.
White Ice Furniture in the lake side lobbies
All furniture in the public spaces is custom designed by us. We insisted to relate the style and materials to the main design elements of the building. The choice of material was the same white corian used for the ceiling chandeliers as it was perfect for seamless and assembly with smooth surfaces. We experimented with CNC cutting to create different types of typography and patterns for the numerous ticket counters, information desks, lobby bars, standing tables and so forth to give each of the furniture pieces a distinctive character. Some of the furniture contains back-lighting to stand out in an evening atmosphere.
Suspended Spiral Stair in the Small Auditorium lake side lobby
Truly special design elements in the public spaces are the suspended stairs – the most spectacular one being the suspended spiral stair in the Small Auditorium lake side lobby. This stair is connecting both lobby levels functionally. The circular form blends in naturally with the circular shapes of the ceiling chandeliers and the lobby furniture.
The entire structure of the stair is suspended from a large lobby ceiling roof window. The structural stainless steel rods are at the same time forming the railings of the stair. All detailing is concealed into the stainless steel design elements. The steps are made of solid strand woven bamboo material.Location: to the North of Jinshi Road, North bank of Lake Li, Taihu New City, Wuxi, P.R.China Architectural and interior design: PES-Architects Project: Wuxi Grand Theatre
Client: Office for Important Urban Projects in Wuxi /Fan Chun Yu, Zhou Jian
User: Wuxi Culture and Art Administration Centre
Floor area: 78 000 m2
Competition: June 2008
Opening ceremony: 30th April 2012