Kew Treetop WalkwayEdit profile
The 200m long treetop walkway at Kew Gardens takes visitors 18m high for a birds’ eye view of Kew, providing the opportunity to experience the forest canopy. The ‘Rhizotron’, entered through an apparent crack in the ground, is a walk-in viewing area illustrating the world of tree root biology. Our aim was to design the walkway to be a visually light, discreet presence, at ease in its natural surroundings; while at the same time being unashamedly man-made. We decided to integrate the main truss structure with the handrail support and drew for its design, on the Fibonacci sequence, which underlies many growth patterns in nature. The progressive number sequence results in a higher density of elements near the truss-ends where the vertical loads are highest. An early decision to use beautiful, low maintenance weathering steel, led to the design of the tapered, triangular pylons and their trifurcated node supports, as this steel is only manufactured in flats. A major challenge was to enable visitors to get as close as possible to the tree canopies without damaging the complex tree root system below ground. A radar survey was undertaken to understand the extent of tree root activity at each pylon location. This enabled us to strategically position the 12-18m long concrete piles between the major roots and led to each pile cap being bespoke. The structure was developed using Gehry Technologies Digital Project. This allowed the design team to develop an ‘intelligent’ model to collaborate with contractors throughout the fabrication of the walkway. The Walkway opened in May ’08 to celebrate Kew Garden’s ‘Year of the Tree’ with over 9,000 visitors on its first day.