Stonehenge is one of the world’s most significant archaeological sites, and receives close to one million visitors each year. The scheme for the new exhibition and visitor center restores a sense of dignity to the treasured ancient monument.
Fulfilling several important aims in the management of the UNESCO World Heritage Site, the project includes improved visitor facilities, better opportunities for interpretation of the stones and the wider site, and most importantly, a substantially improved landscape setting in which to appreciate Stonehenge.
Existing visitor facilities and car park have been re-located to Airman’s Corner, approximately 2.5km from the stones,westward along the A344, out of sight from the monument. A low-impact shuttle service transports visitors from the new center to the stones.
The architectural composition of the new center is simple yet distinctive, sensitive to its surroundings and to the significance of the monument. It not only provides essential visitor amenities but also, for the first time at Stonehenge, exceptional interpretative exhibitions and dedicated educational facilities which will allow a greater understanding and enjoyment of Stonehenge and the wider site.
The new building is a single storey structure that sits delicately in the landscape. The exhibition and visitor facilities are designed as a group of two self-contained pods, slid beneath a light, non-reflective metal canopy roof, which floats above. The metal roof is perforated and undulates to reflect the rolling landforms of Salisbury Plain and is supported by some 200 randomly arranged slender columns. The visual effect of the canopy overhanging the pods on the ground gives a transitory and temporary sense to the center. This ensures that the solidity and timelessness of the stones is not compromised or visually diminished by the new structure.
Beneath the canopy is a glass pod housing the cafe, retail and education spaces, and a solid timber-clad pod containing the exhibition space, information and toilets. Aiming not to enclose the visitor, the floating canopy defines and shelters, with views and movement directed out into the broader site, encouraging an outdoor landscape experience. The building is robust to withstand the high visitor numbers, and has a low carbon footprint given the use of local and renewable materials wherever possible.
Sustainable Architecture Description
The Stonehenge Exhibition and Visitor Centre was designed to be sustainable and incorporates natural ventilation, mixed mode ventilation, passive solar shading and optimizes the use of natural light to reduce the energy requirements of the site. The use of a borehole for the provision of potable water and low water WC’s and basins, combined with on-site sewage treatment, all reduce the carbon footprint of the building.
The heating to the center is provided by an open-loop ground source heat pump system. Refrigerant based cooling is only provided to areas such as server rooms which have a load that cannot be met by natural ventilation and an under floor cooling system which serves the remainder of the space.
Accurate control through the use of local thermostats and carbon dioxide sensors plus thorough commissioning, ensure that system performance is optimized and energy wastage is minimized.
In addition to the above ground impact, the exhibition and visitors center has been designed to be ‘reversible’, meaning that minimal impact to the landscape will occur if the center were removed.
At the Hub building, heating is provided via the use of an air-water heat pump and distributed in the form of low temperature hot water to serve radiators.
CRYSTAL CLEAR GLAZING PUTS STONEHENGE VISITORS IN TOUCH WITH THE LANDSCAPE
The design concept at the heart of the new Stonehenge visitor centre which opened at the end of last year, was a building that would blend unobtrusively into the wide-open Wiltshire landscape by evoking a copse of trees.
To achieve this effect, the two main enclosed spaces that make up the building are covered by a light, gently curving roof, supported by a forest of slender angled columns.
The interior spaces offer visitors two starkly contrasting experiences, one an atmospheric exhibition space clad in timber planking and the other a bright and airy café, shop and educational area encased in stunning Pilkington Optiwhite™ extra-clear, low-iron glass.
Terry Lidster, sales engineer at Pilkington Architectural, says: “The idea behind the glass pavilion was to connect the interior of the building with the striking landscape that surrounds it on all sides.
“The architect wanted the interior to be both visible from outside to entice people in while, more importantly, allowing those inside a view out that was as bright and naturally coloured as possible. For this reason, the glass selection was paramount, and maximum transparency was key.”
Elegant yet robust
The project presented a structural challenge for the glazing system, as architects Denton Corker Marshall were keen to increase the feeling of space inside the building by maximising the height of the glazing. At 4.3 metres tall, the glass needed to be thick and strong enough to stand up to the force of the high wind acting on it, and also meet building regulations for low-level glazing.
Adding to this challenge was an aesthetic requirement to avoid any exterior bolts on the glass.
To meet this brief, the Pilkington Planar™ Intrafix structural glazing system was specified, with high-level perpendicular glass fins positioned at the join of each pane in order to secure it to the edge of the roof while keeping the fixings as hidden as possible and the floor area free for displays.
Anthony Williams, contracts manager at Vitrine Systems explains: “The glazing we provided gives the appearance of an almost free-standing, delicate wall of glass, while in fact the system has a great deal of structural strength and is, of course, solidly fixed to the building.
“The way the fixings are hidden helps maintain the clean lines of the pavilion, with the top and bottom of the glass sitting in channel rebates within the floor and ceiling, while the fins provide additional lateral strength and help to anchor the system to the roof structure.”
With all four sides of the pavilion consisting of high glass walls, the ability of the glass to retain heat was another priority for the designers.
To address this, Pilkington K Glass™ OW was used for the outer pane of the double glazing system, which comprises a low-emissivity coating on the inner face of the outside pane of glass, reflecting heat back into the building.
Terry Lidster adds: “The wide range of Pilkington products we manufacture enable us to create bespoke combinations project by project.
“For the Stonehenge scheme, the use of Pilkington K Glass™ OW as the outer pane and toughened Pilkington Optiwhite™ as the inner pane, delivers the best of both worlds in terms of allowing the maximum amount of energy and light from the sun to enter the building and help to heat the space, while at the same time minimising the amount of heat loss. The 16mm argon-filled cavity between the panes ensures conduction of heat through the glass is also kept to a minimum. The result is that the sweeping views and light filled pavilion enjoyed by those inside the centre do not come at the expense of energy efficiency.”
VMZINC perforated composite panels at Stonehenge Visitor Centre
Sitting delicately in the landscape, the new Stonehenge Visitor Centre facilities are designed as a group of self-contained pods that slide beneath a light, perforated metal roof that appears to float. To create the effect, 3600m2 of VMZINC composite panels in quartz-zinc were used for the underside of the soffit. An elaborate pattern of perforations was cut into the panels, which are made up of two 0,5 mm thick zinc sheets bonded either side of a mineral-rich polyethylene core. Despite the thin 4mm profile of the roof build up, the panels are exceptionally rigid and dimensionally stable. The effect gives a transitory and temporary feel that does not enclose the visitor nor visually diminish the solidity and timelessness of the stones.
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The immediate visual aesthetic of the £27m Stonehenge visitor centre stems from its glass and timber facades and 211 canted steel supports. At closer quarters, however, the canopy takes the eye, 3600m2 of VMZINC Composite panels in QUARTZ-ZINC® having been used for the underside soffit. An elaborate pattern of perforations has been cut into the panels which are made up of two 0.5 mm thick zinc sheets bonded either side of a mineral-rich polyethylene core. Despite the thin 4mm profile, panels are exceptionally smooth, rigid and dimensionally stable. As a result, lengths of up to 6 metres can be installed.
A natural palette suited to the rural landscape was a key element of the brief and zinc was chosen for its sustainability, colour retention and self-protecting patina. The design had to demonstrate reversibility and sit lightly in the landscape so a steel structure with lightweight framed walls was specified. The minimal substructure will present little environmental impact if the building is ever removed and its low lying, remote location minimises visual intrusion.
Attention of up to 1,000,000 visitors each year will be drawn to the zinc by the height of the building which, at up to 8 metres is comparable to the tallest trilithon stones. Local, recyclable and renewable materials were used where possible and VMZINC was able to demonstrate that over 90% of material recovered from construction projects at the end of its design life is already being recycled. Energy consumption in manufacturing and air emissions are by far the most impressive of any metal façade or roofing system. Zinc concentrations in the Rhine, which passes through one of Europe’s areas of greatest industrial intensity, are also well below accepted environmental limits.
Zinc has, in addition, been used for cladding the pod housing ticketing and guide facilities. It provides a notable contrast to the timber and glass without suggesting that the materials in any way clash. With zinc colours now including blue, green, red and brown the design scope it provides has never been greater.