To overcome the lack of horizontal space for agriculture in the city, the Columbia University professor Dickson Despommier decided to concentrate the cultivation of basic foods in vertical structures, calling them Vertical Farms. These are a new way of farming based on layered and self-sufficient urban buildings, able to accommodate the growing of organic natural foods. In this sense, the Farm Tower is characterized by the power to melt the distinctive elements of the Vertical Farm and typological characteristics of the residential tower. The main methods of indoor growing are two: hydroponics and aeroponics, which exploit the contact of the roots with water without the use of soil or medium aggregates.
The project site is located in the City of London, near the City Hall, the Tower Bridge and the Shard by Renzo Piano.
For the design of the skyscraper it's chosen a "concept " very close to the natural world: a fractal composed of two geometric shapes with a strong symbolism: the circle and the triangle. The plant is therefore composed of these two geometries, that are repeated and alternated at different scales, with three orders of magnitude for circumferences and three for triangles. The plant changes at all levels and from a pure circle on the ground floor is transformed first into a triangular shape on the middle floors and then finish with a trefoil shape on the top. This transformation doesn't take place in a chaotic way, but follows the strict rules of the Fibonacci series: each Fibonacci number is the same number of floors with the same plant and a transformation in the volume, which becomes more articulated with increasing height. In addition, any change of number in the Fibonacci series, corresponds to a mutation of use, in fact the skyscraper contains many features:
- 40% farm;
- 40 % residential;
- 15% commercial ;
- 5% services.
For the casing it's exploited the transparency and lightness of the glass with a thin but stable structure of steel, which form a dense network, as if it was the texture of a fine cloth. The innovative composite techniques allow to realize the most varied geometrical shapes, through the "triangulation" of the surfaces, adapting to the sinuous lines of the building. It is a diagrid structure, where the vertical forces, as well as the horizontal ones, are absorbed by a grid of diagonals placed on the facade of the building. The diagonals absorb the shear produced by the horizontal actions in much more efficient way of the vertical elements, and also the location of the structure in the facade increases the height of the section allowing you to efficiently absorb much of the bending and decreasing the phenomenon of "shear lag".