Mexico City - The contract for the construction of the terminal building at Mexico City's new airport has been awarded to a consortium led by a company owned by Mexican billionaire Carlos Slim. The consortium headed by Cicsa, or Carso Infraestructura y Construcción, won the contract with a bid of 84.828 billion pesos, nearly US $4 billion.

Two other groups bid on the job, the biggest contract in the airport construction project, whose total cost is an estimated $13 billion.

Work on the 743,000-square-meter terminal building is to begin this year, with completion scheduled for 2018. It will be the world's third-largest after Dubai and Beijing, with capacity to serve up to 68 million passengers a year when the first phase is completed.

The design for the new facility revolutionizes the way that airports are conceived – the entire terminal is enclosed within a continuous lightweight gridshell, embracing walls and roof in a single, flowing form, evocative of flight.

The airport's ultimate capacity is forecast to be 125 million. The existing airport, operating at the limits of its capacity, handled nearly 40 million passengers in the 12 months ending May 31 last year.

Grupo Aeropuerto de la Ciudad de México (GACM), the state-owned firm responsible for the airport project, said the winning consortium would receive an initial deposit of 84 billion pesos, or 30% of the total. within the next 30 days so that construction could begin.

GACM general manager Federico Patiño said one of the reasons Cicsa won the contract was the promise to complete the project 20 days ahead of the date stipulated in the bidding documents.

Other firms in the consortium are ICA, Mexico's biggest construction company, and the Spanish companies FCC and Acciona.

Another consortium, led by Portuguese company Mota Engil, bid just over 90 billion pesos while the bid from a third group, led by Omega Construcciones de Mexico, was rejected for not meeting working capital requirements.

An official in the federal Communications and Transportation Secretariat said the new airport's two runways, control tower and terminal building would be completed in 2018. The airport is slated to begin operating in 2020.