In Ildefonso Cerdá’s plan for the extension of Barcelona (1859), the Diagonal avenue ended in a vague square by the sea but did not actually reach it. On the occasion of the Olympic Games (1992), the beltway (Rondas) surrounding the city was built. The Diagonal avenue would necessarily have to jump over this ring-road in order to approach the water. It was only six years ago that the last 3 kilometres of this avenue were opened to the traffic, from the “Glories” square until it reached the beltway. This last operation has finally established an order that was first envisioned over 150 years ago.
Both the recent construction of a downtown as the end to the Diagonal avenue (in the vicinity of a water treatment plant, a garbage incinerating plant and a power station) in one of the very few areas with unoccupied soil in a very dense city; and the occasion of the “Fórum Barcelona 2004”, have finally allowed the avenue to reach the sea. As truthful proof of the sustainability principle the Forum endorses, housing, hotels and public facilities exist side by side with the aforementioned city plants (power, water treatment and garbage) that up until then had been frowned upon by the city’s inhabitants.
The Forum esplanade, a support for the Forum building and the new Convention Centre (CCIB), shaped like an open hand or a delta, is a 14 ha. extension of the Diagonal avenue that covers a large part of the newly extended water treatment plant. The Diagonal avenue rises steeply, in order to jump over the beltway (Ronda Litoral), from the 4.5 meters over the sea level where its use as a traffic artery ends, until it reaches 17 m and starts descending slowly towards the sea.
This roof can be seen as a cloth, an image that the asphalt pavement- a huge 5 colour patchwork- refers to quite explicitly. The asphalt permits repair work that, by unexpectedly changing the original colours, will enrich the chromatic range. A pavement that is also a complex technical floor under which power lines, water pipes, telephone lines and a drainage system form a dense network. The future uses will imply unforeseeable occupations of this esplanade. The temporary constructions that have been built for the Forum 2004 event are the first example of these series of ephemeral architectures.
Over this esplanade emerge chimneys- one of which is being transformed into a meteorological, orientation and information point- and services of the water treatment plant. Some high buildings of the plant emerge oblivious of this roof. On this asphalt surface, two folded canopies have been built to provide shadow, as well as two large hypostyle halls- the structure of which is coincident with that of the underlying water tanks on which it rests. These two large concrete canopies, which are open on all four sides, will hold a metallic shed structure (whose north face will be glazed and whose south side will be covered with 6.500 m2 of photovoltaic cell panels) that will provide a 13.000 m2 roof for the esplanade.
The fingers of the esplanade rise in such a way that they form a series of cliffs over the new marina, while the interstices among them house ramps and stairs that allow people to descend to the port. In three of these fingers, large areas of grass have been planted to signal sun-bathed leisure areas. A ha-ha with stairs in all the perimeter of these fingers guarantees a clear horizon, uninterrupted by parapets or handrails.
The two fingers located closest to the sea house the “Dry Marina” and the Sailing School. The former extends with a pedestrian bridge over the Marina while the latter holds a large photovoltaic canopy (4.500 m2) that will be seen in Barcelona’s waterfront as yet another of the industrial facilities that are so characteristic of this area.
The canopy receives sunlight and produces energy and a cane-like shadow. It is a skewed plane, with a 30º inclination and oriented due south, supported by 4 twisted legs that stick out of the Sailing School finger. The roof of this building is a geometrically unexpected end to the Diagonal avenue, the last viewpoint or belvedere of the city over the water which can finally be reached descending a large staircase “under a pallium”.