Millennium Dome Building
GENERAL DESCRIPTION
1. SUMMARY
The Millennium Exhibition is to located on a 130 acre site on the Greenwich
Peninsula, accessible by both land and water. The site is to contain a variety
of performance spaces and exhibitions, with the main activities taking place
towards its northern end, bounded by the river Thames.
The main exhibition is to be housed within a spectacular and unique dome,
providing shelter from the inclement British weather. The 320m diameter dome
will be suspended from a series of twelve 100m steel masts and will be held in
place by over 70 km of high strength cables.
Enclosed by a translucent, weather proof fabric, the interior of the
exhibition building will be light and airy, with sufficient size and flexibility
to house a number of large special events. The building will be capable of
accommodating 40-50,000 people, and in addition to the exhibition itself will
have generous provision for food and drink outlets, as well as well as a wide
range of shops.
The resulting Exhibition Building will have a circumference of 1 kilometre
and a height of 50 m at its centre. This will give it a ground floor area of
over 80,000 m2 making it approximately twice the size of the Georgia Dome,
currently the largest building of this kind in the world. The enclosure will be
tall enough to house Nelsons Column, and large enough to cover two Wembley
Stadiums. At night the translucent dome will glow spectacularly providing a
beacon for Greenwich into the next millennium.
2. ARCHITECTURAL DESCRIPTION
The exhibition site will be served by a west entrance from Millennium Central
tube station and bus terminal, by a south entrance from Central Park and the
coach and parking areas and by an east entrance from a new river boat pier.
These entrances will open out onto the main plaza, with sheltered edge walks
allowing the visitor to access the main Exhibition Building in inclement
conditions.
The Exhibition Building will be formed by a simple, strong and expressive,
structure responding to the huge scale of the Greenwich Peninsula and the River
Thames. Its envelope will be formed by a 320 m diameter cable net membrane
structure with a maximum internal height of 50 m. The cable net will be
supported by twelve principle masts, each approximately 100 m long and anchored
to the ground at the edge of the building by twenty four groups of main support
cables.
The Exhibition Building is conceived and designed to provide all year round
weather protection. This protective envelope will provide an early construction
umbrella within which the exhibition contents may be constructed, offering a
flexible enclosure within which the various exhibition elements and visitor
experiences can be deployed in spatially diverse ways.
The interior of the building, covering an area more than twice that of
Trafalgar Square, will provide a huge internal open space surrounded by a
peripheral ring of accommodation housing six service and support nodes. These
nodes will accommodate entry and exit points, delivery and service facilities,
technical plant and equipment areas, toilets, staff support areas, maintenance
areas, storage and other technical requirements. The peripheral ring will also
house groups of lifts, stairs and escalators providing vertical access to a
public mezzanine level.
The mezzanine level will form a complete ring of public accommodation
approximately 7 m above the general exhibition, providing a prime location for
restaurants, cafes, bars, view points, exhibits and additional support areas.
The outer face of the mezzanine is to be a frilly glazed external wall offering
panoramic views of the Thames, the plaza and Central Park. Outside the glazed
wall, directly contiguous with the mezzanine, a kilometre long boardwalk will
encircle the building, providing entry and exit points and an external promenade
under the sheltering edge of the great canopy.
The Exhibition Building is to be linked to its site by a sloping landscaped
berm that will completely encircle it. The berm will serve as a unifying screen
for technical support activities and service plant areas and will also provide
six external loading bays, each with space for four trucks.
At the edge of the Exhibition Building, twelve exhibition spheres will be
placed at equally spaced positions around the perimeter. The 20 m diameter
spheres, will provide small scale specialised exhibit areas accessible directly
from the mezzanine boardwalk. In addition to their exhibition role, these
spheres are intended to provide sculptural counter points to cable net.
The cable net, the berm, the ring of masts and the twelve spheres, together
will form a huge and dramatic sculptural composition on the river edge. The main
membrane envelope will be divided by twelve translucent interpanels articulating
the structural support masts and expressing the entry and exit points from the
building. At night this perception of the structure is revered as the
translucent interpanels reveal the interior of the building.
Flood lighting of the masts from the interpanel segments, the narrow
illuminated glazed edge facade and the accompanying floodlit spheres will form a
dramatic composition deliberately designed to exploit its riverside location and
the reflective potential of the river surface.
3. TECHNICAL DETAILS
The primary structure comprises 72 radial cables in pairs of 32mm dia strand.
In total there is over 70 km of cable suspended from twelve 100m long masts. The
overall resulting diameter of the dome is 320m, with a clear span of 200m
between the main structural masts and a maximum height of 50m.
The cables carry both wind uplift and downloads in the same way, resulting in
a very efficient structure. This inherent efficiency, combined with the
aerodynamic shape of the envelope, means that loads should be small enough to be
carried on conventional pad foundations. Differential settlement of the masts
then will be catered for by jacking up the base connections as necessary.
The primary cables are to be infilled with a double layer skin of high
strength coated fabric. The fabric is to be connected to the cables via
aluminium extrusions with a luff groove and a keder edge on the fabric. The load
in each of the radial cables will be transferred to the ground by four anchors
either screwed into the terrace gravel layers or drilled and grouted were ground
obstructions are encountered.
It is intended to found the dome on a plain concrete base to allow
flexibility of layout for the exhibition itself The perimeter structure, housing
services, retail and food/beverage outlets is being designed to be lightweight,
flexible and easy to assemble/disassemble with the potential for re-use. This
suggests the use of steel frame with a prefabricated infill system such as
concrete planks or profiled metal deck with power floated concrete floor.
Enclosed by a weathertight envelope, the Exhibition Building contents will
not be subject to the usual constraints of external construction. As a result,
internal pavilions need not be sealed or weathertight, other than where fire or
acoustic separation is required.
The environmental strategy adopted for the Exhibition Building must be
flexible, to provide freedom for the exhibition content. The main service areas
will be located within the perimeter structure, feeding from six 600 segments
into the central exhibition. Primary servicing equipment will be located within
the berm structure at the edge of the building. It is intended that this
equipment is manufactured off-site in containerised units, minimising the
installation time and maximising the potential for reuse. Utility infrastructure
can also be confined to the perimeter.
Services will run in dedicated routes from the perimeter to the centre
directly below ground or mezzanine level. Any large scale enclosures within the
exhibition area itself will be largely self contained, but may be 'plugged in'
to the perimeter structure as required for access to the chilled water, water
services, drainage, electrical and communications infrastructure.
The high heat gain from the exhibition lighting and associated equipment, is
likely to mean that space heating requirements will be low. Cooling however,
will be required particularly during the peak summer months, together with a
means of introducing fresh air to the more densely populated areas. it is
anticipated that this cooling load can be met by the provision of packaged
chiller units linked to a river water ring main.
Air movement through the dome will be induced by extract fans located in a
central 'hub' in the roof structure and within the main masts themselves. This
system will be assisted by additional supply fans located above the pedestrian
and delivery access nodes.
|
