An unprecedented landmark for London
The Millennium Dome is the largest domed-shaped tensile structure in the world. Built to herald the dawn of a new millennium, its design was inspired by time and the heavens. Architects and design experts from Richard Rogers Partnership and Imagination tracked the trajectories of stars and comets from dawn until dusk, plotting their celestial paths onto early concept models of the Dome. Today the panels of the canopy are based on the cosmic lines of longitude and latitude.
The Greenwich Meridian Line, which passes just meters from the Dome, provided additional inspiration with allusions to the concept of time within the design. The 12 support towers represent the 12 hours, 12 months and 12 constellations of the sky. The Dome is 52 meters at its highest point, representing the 52 weeks of the year. Each span is 365 meters apart, symbolic of the numbers of days in a standard year. There are 24 scalloped edges at the base of the canopy, for each hour of the day. Time and space were literally of the essence to the Millennium Dome Project.
An exceptional accomplishment of engineering and architecture, the vast canopy, which encompasses a volume of 2.2 million cubic meters, was built at break-neck speed from initial concept to execution in only two years. It was also extraordinarily important that the space remain highly adaptable to any number of future uses. Given these requirements the most logical solution was a tensile structure. Despite its massive size the entire structure of the roof is ultra-efficient and relatively lightweight, so much so that the total weight of the structure weighs less than the air contained in the building. In light of all of the extraordinary accomplishments of the Millennium Dome project, the team won the highly coveted Royal Academy of Engineering MacRobert Award for Innovation, the first construction project to win this prize since the Severn Bridge in the 1970’s.
Set on the south bank of the River Thames, the site of the Millennium Dome presented a multitude of challenges to the project teams. The land had once been owned by British Gas and was used to dispose toxic waste. The government, at great expense and with much effort, had to see that the land had been thoroughly decontaminated before construction could begin. Moreover a ventilation shaft from the Blackwall Tunnel stood on the designated dome site, and thus needed to be accommodated into the structures’ design.
After careful consultation with Buro Happold it was determined that the best solution would be an economical, lightweight tensile dome-styled structure that would enable a swift construction to address the short and inflexible time constraints. The other advantage of dome-shaped roofs is that they allow for a wide variety floor plans and configurations due to the wide placement of the support towers. The Greenwich Peninsula was selected as the site in 1996 – which is very late in a time line used in a project of this scale. The Millennium Dome had to be completed by 1998 to allow enough time for exhibitions for the Millennium Experience to be installed. Rather than building separate pavilions, it was much more cost-effective and time-efficient to use a tensile structure to enclose the entire space.
The Millennium Dome features twelve 100m high steel masts that support a tensioned net of seventy kilometres worth of steel cables, arranged radially on the surface of the roof and held in place by hanger and tie down cables. The canopy itself is a one millimetre white PTFE (polytetraflouroethylene) fabric with an interior lining designed to reduce thermal gain, and improve thermal and acoustic performance – in essence absorb both sound and condensation. The Dome is naturally ventilated with openings at the centre of the roof to allow rising hot air to escape, while 12 fans work to draw cool air from the outside, in.
As aforementioned one of the advantages of a tensile structures is the ability to easily modify interior spaces. We took this degree of flexibility further by positioning the 12 service cylinders outside the perimeter of the Dome to create a ‘flexible racking system’. Our building services engineers cleverly opted to house the primary electrical and mechanical plants in these cylinders, in keeping with the architect’s aesthetic desires. The facade of these cylinders were outfitted with exterior fins which can be easily detached, to service and remove the plants as needed.
Sustainability is consistently a concern for our team. Great care was taken with the design of the Millennium Dome to minimise the environmental impact. Rainwater runoff is collected, naturally filtered through the reed beds and recycled as grey water for the toilets. The translucent PTFE canopy allows some sunlight to filter into the Dome thus reducing the need for interior lighting and lowering power usage. The energy which is needed for the facility comes from renewable sources, such as household waste, sewage and wind power.
The Millennium Dome was delivered within 15 months, under-budget and at a relatively inexpensive cost of £43 million, which is a remarkable achievement in light of the scale of the project. Given the inherent flexibility of the design, the Dome site was transformed into a 20,000 seat arena for the London 2010 Olympic Games. Today the Millennium Dome houses the O2 Centre, which based on ticket sales, is one of the most popular concert venues in the world. Inspired by the dawn of a new millennium and the multi-faceted value of time, the Dome stands as an unprecedented landmark to the human spirit of optimism, creativity and innovation.