Located approximately 10 kilometers (6 miles) north of the city, with a metro connection planned, the new Sondica Airport terminal is situated across the apron and runways from the original terminal. Within this new facility, there is considerable potential for future expansion. Sondica Airport was able to handle 2 million passengers per year when it opened in November 2000. By 2005, the airport was handling 3.8 million passengers annually (25% of international flights) and 4000 tons of cargo. Sondica Airport will ultimately be able to accommodate up to 10 million passengers a year. In 1990, Bilbao Airport had reached the limits of its development.
Located to the north of the city, on the coast of the Bay of Biscay, the facility had been built to cope only with domestic flights and could not function as a transportation hub for the growing Basque region north of Bilbao. The Spanish airport authorities accordingly asked Calatrava to design a new terminal with four embarkation gates, which would comply with international air transport standards. In 1994, in response to the increased number of flights to this quickly developing area, the authorities requested a second, enlarged proposal for passenger facilities, this time with a total of eight gates.
The organizational and architectural center of the complex is a large glazed hall. As the steel structure of the aerodynamic roof sweeps upward in the direction of the airfield, it spans the administrative areas, restaurants and waiting areas. Located behind the canted glazed facades, these waiting areas directly overlook the apron and runways. The triangular plan of the hall follows the natural flow of passengers toward a transverse linear walkway that leads to the gates. A generously curved, glazed entrance on the north side of the terminal allows full use of the 36 meters (118 ft) traffic drop-off area. The elevated upper level of this vehicle access is for departures; the lower level is for arrivals. In non-glazed areas, the concrete structure of the east and west wings is clad in a unifying skin of aluminium.
The terminal is connected by a 100 meters (328 feet) subterranean passageway to a four-story parking garage, which can accommodate 1500 vehicles. The garage is partially recessed into a landscaped rise. In this way, the parking structure is integrated into the complex both functionally and visually, as is too rarely the case at airports. In another design initiative that will encourage overall coherence, Calatrava's plan for the airport accommodates provisions for the future construction of auxiliary facilities, such as hotels and a recreational complex. Covering the open platform is a curved canopy made of transparent glass, which allows light to filter down to the subterranean passageway through prefabricated glass-brick elements laid in the platform. The client wanted to connect the underground passages to create a shopping precinct.
Concrete supports were cast in place using one-piece formwork, which was moved and adjusted to the gradient for each new casting. The exposed concrete ceiling appears to be two separate elements that meet at the center but is actually one continuous, undulating surface. Despite the complexity of its shape, this ceiling proved to be cheaper to build than a suspended structure. The need to close the station at night resulted in the development of hydraulically activated devices to shut the entrances and in some cases protect them from the weather.
1990 - 2000