Concrete Treasure Buried Underground (2010)

In designing the panels Purvis sought to convey the importance of the ceramics industry, in particular Crown Lynn Potteries, to the development of New Lynn and the early infrastructure of greater Auckland. The profiles of the panels echo the surrounding landscape, from which the clay that supplied New Lynn’s original brick and pipe manufacturers was sourced, and through which the rail trench is cut. The panels’ underlying reference to the fluid New Lynn landscape, with its distinctive volcanic ripples, was also very much part of Purvis’ desire to soften what could potentially have become a cold and unwelcoming locale. “I wanted to make something that was quite organic within a built environment that has lots of straight horizontal and vertical edges.” says Purvis. “I wanted to make the concrete appear more liquid and less hard.” Although cast from only four basic moulds, each with a positive and negative variation, the panels have been skilfully arranged by Purvis to escape any discernable pattern. Aside from their decorative purpose, the panels conceal a range of power and fire-control services. The panels also act as acoustic buffers, with their uneven surface disrupting the sound generated by passing trains to reduce reverberation within the trench. The decision to go with GRC was based primarily on weight considerations for transporting, handling and fixing the panels. GRC is a composite material, containing of hydraulic cement, silica sand, alkali resistant glass fibres and water. The glass fibres effectively reinforce the mortar mix to enhance its tensile strength, and allow for a thinner and lighter panel. Interestingly, the panels were attached to the trench wall using stainless steel fixings. This eliminated the need for steel backing sheets or frames, and therefore any potential issues with corrosion. In total, 258 panels, each weighing 400kg and comprised of two sub-panels (one negative and one positive profile),were manufactured using a spray system by GRC New Zealand Ltd from moulds based on Purvis’ foam/fibreglass sculptures (or ‘plugs’). While the manufacture of the panels themselves was relatively straightforward, ensuring GRC New Zealand met Purvis’ requirements for the correct positive/negative combination and sub-panel 90orotation called for careful monitoring. For Bill Haigh, General Manager of GRC New Zealand Ltd, the New Lynn rail trench has been a rewarding experience on many levels. “Initially posing challenges from a mould perspective, the panels then generated a lot of interest from visiting architects and designers to our yard,” says Bill. “The project also enabled us as a local company to create employment, develop the industry’s skill base and make a real contribution to a community project. Then to see the panels erected in the trench – that was really exciting stuff.” As West Auckland’s integrated urban and rail development continues apace it is heartening to see careful construction detailing recognised as importance by key decision makers. This is nowhere more evident than in the New Lynn rail trench relief panels, which through the unique properties of GRC will enable rail commuters to enjoy the work of one of New Zealand foremost sculptors while benefiting from more frequent and reliable passenger services.