The U.K.'s £1.2-million Solar Pyramid
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COLOURED STAINLESS steel will be used to clad three 40-metre-high gnomons in Derbyshire, England.
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SHADOWS CAST by the gnomons onto a stone piazza will indicate the time of day.
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DESIGNERS Adam Walkden and Richard Swain chose nickel stainless steel for its durability, versatility and
recycling potential.
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THIS MODEL shows how the three gnomons form a pyramid shape. Construction is to begin in April
2003.
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This coloured stainless steel sundial will be the world's largest. By Virginia
Heffernen
Nickel magazine, February 2003 --The world's largest working sundial, a pyramid
clad in "coloured" stainless steel, is expected to mark the longest day of the year when it opens on June
21st, 2004.
The 40-metre high "solar pyramid," a confluence of vertical triangular planes, will dominate the skyline adjacent to the M1 motorway in Derbyshire, England (just a few kilometres, incidentally, from where stainless steel was discovered 90 years ago by Sheffield metallurgist Harry Brearley).
The design consists of three gnomons, or planes, constructed of mild steel and inclined towards each other at an angle of 53° to create a pyramid shape. The gnomons will tell time by casting shadows across a 50-metre-wide stone and brick piazza.
What sets the sundial apart from most metal sculptures is the cladding: a mirror-polished, coloured S31600 stainless steel developed by Rimex Metals, a specialist in metal finishes and one of the sponsors of the project.
The designers of the solar pyramid, Adam Walkden and Richard Swain, chose the material for its durability and versatility. They also appreciate the way the mirror finish reflects the perpetual changes in land and sky.
"The illusion of colour created by the process captured our imaginations and seemed perfect for this situation," says Walkden. "The ability to silkscreen images and logos onto the material was also important," he adds.
Rimex Metals' Colourtex process does not use paints or dyes, says Rimex representative Keith Wilson, but instead takes advantage of the passive oxide layer that gives stainless steel its corrosion resistance. By immersing the steel in a hot solution of chromic and sulphuric acid, Rimex increases the thickness of this oxide layer, thereby enhancing the natural phenomenom of light interference and creating colour. For a simple analogy, imagine the colours generated when oil floats on water.
Rimex produces a range of colours, including champagne, black, blue, gold, red and green, depending on the thickness of the oxide layer. The company can also adjust the appearance of the steel from matt (dull) to lustrous by adjusting the surface texture. In any case, the steel remains colourfast, even when exposed to the elements.
The ColourTex process enhances the cladding on several other architectural projects worldwide, including the Experience Music Project in Seattle, Washington, U.S.A., a Frank Gehry design inspired by the bright hues of electric guitars. On this building, red and blue painted aluminum is interspersed with 10,000 square metres of stainless steel shingles in red and gold to create a myriad of colours designed to symbolize the energy and fluidity of music.
Walkden and Swain have selected green as the dominant colour for the solar pyramid, but hues will vary depending on the angles of natural light and the perspective of the viewer. At night, the pyramid will be illuminated. The design team is exploring the possibility of using self-generating photo voltaic cells for the lighting.
A three-dimensional, welded tube framework, assembled in a fabrication shop and then transported to the site in manageable sections, is designed to support the cladding and resist the stresses of wind loading. Each gnonom will have a piled foundation to protect the structure from ground movement.
Walkden says construction is scheduled to begin in April, 2003 and finish in time for the summer solstice on June 21st, 2004. About one third of the £1.2 million needed for the project has been contributed by sponsors. Fundraising for the remainder is ongoing, and the designers are still seeking a major sponsor interested in having the pyramid bear its name.
Construction will be followed by British television station "Channel 5", while BBC's Blue Peter, a top
children's program in the UK, will run a nationwide competition to design the seating areas at each of the 12
hour positions on the dial.
Virginia Heffernan is a Toronto-based science writer.
Photos: RIMEX METALS/ART IN THE ENVIRONMENT
 Adam Walkden or Richard Swain (Designers) |
