Awards: Wales Millennium Centre

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Awards Judges sing praises of steel opera house The Wales Millennium Centre, the new home of the Welsh National Opera, threw over some outdated views about the suitability of steel for auditoriums, and is now a winner of a major European steel design award. Clad in rough-hewn slate and timber and with a noise being transmitted from the structure into the FACT FILE central stainless steel-clad auditorium, the Wales theatre. Wales Millennium Centre Millennium Centre has endured sniping about its ap- One of the key components is the flytower, which Architect: pearance. But Cardiff’s landmark theatre and opera houses the theatrical equipment needed for the Capita Percy Thomas house, constructed on time and to budget within 33 stage. It has to be twice the height of the visible area Structural Engineer: Arup months, has been recognised for its innovative use of the stage to allow scenery to be lifted out of the Main contractor: of steel in the 2005 European Convention for Con- audience’s view. Unusually, the architect merged the Sir Robert McAlpine structional Steelwork Design Awards. tower and auditorium into a single curving unit, clad Steelwork contractor: The lottery-funded building contains an 1,800 seat in chemically weathered stainless steel. Watson Steel Structures Project value: £106M theatre which is the home of the Welsh National The flytower columns are about 35m tall with Steelwork tonnage: Opera, but is designed to house a range of activities design axial loads of up to 11,000kN. Iain Hill, 5034 tonnes. from opera and ballet to musicals. Design Director of steelwork contractor Watson The theatre’s designers — architect Percy Thomas Steel Structures said the tower was one of the most Partnership (now Capita Percy Thomas) with Arup challenging parts of the structure to erect. “It was as structural engineer — challenged conventional fairly complex in design and erection. It needed wisdom by choosing steel as a framing material. carefully-designed temporary works and careful Arup Director Chris Jofeh, writing in New sequencing to keep it stable during construction.” Steel Construction in February 2004, said: “It was Storey-high trusses span over the building often thought that, because of the complicated to support the roof. Their upper booms carry a geometry of balconies and the need for massive concrete/metal decking roof slab while the lower walls, theatres were best constructed from in-situ booms support a ceiling formed of precast panels reinforced concrete.” This was challenged by a with an insitu topping. These two layers between The curved central mass number of Arup-engineered theatres in the US, them provide sufficient isolation to keep out aircraft of the building houses the which “showed that steel-framed construction was noise. auditorium and fly tower a credible alternative to concrete”. Composite floors Mr Hill and the leader of Arup’s structural team, using normal and lightweight concrete on profiled Lorraine Bradley, went to the ECCS Annual Meetings metal decking “proved practical, even in regions of in Nice last month to collect the award. changing three-dimensional curvature such as the The judges praised the project in glowing terms: theatre balconies.” “The Wales Millennium Centre demonstrates that Advantages for the Cardiff project included the steel has substantial benefits to design teams even speed with which the primary frame could be erect- when acoustic parameters are important. The design ed and made watertight, allowing early commence- team effectively used a wide range of different ment of the installation of services and theatrical structural elements to achieve a most exciting equipment; and the ability to separate the design of solution. The use of steel in an auditorium is novel. the frame while the architectural and acoustic de- The use of different materials, because of the sign continued to evolve. location of the structure, has been satisfied by the A lighter steel structure could have been more design team in a most striking manner.” susceptible to vibration than a concrete one, it was Speaking before travelling to the awards thought, but three-dimensional vibration analysis ceremony, Mr Hill said: “We’re very pleased to get showed that even the main theatre balconies, which recognition of a difficult job done well.” cantilever 10m, showed the concerns to be unfounded. Arup’s Jofeh added: “We’re obviously delighted. The superstructure is divided into a number of It’s a credit to a team who worked long and hard on structurally separate buildings, to prevent unwanted the project.” 12 NSC October 2005


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