The last stretch of rock that separated the Subway Line 4 tunnel between the neighborhoods of Barra da Tijuca and São Conrado was detonated on the morning of December 9. The two points were joined at the site of the road Estrada das Canoas, located in São Conrado. The conclusion of these excavations, which began in September 2010, represents a milestone for the Subway Line 4 construction work (Barra da Tijuca-Ipanema): extending 5 km, this is the world’s largest tunnel between subway stations.

“In the underground lines alone, we are building with Line 4 more than everything that has been completed since when the subway was first opened,” explained Rio de Janeiro Mayor, Sérgio Cabral, who was present at the event. “We will allow more than 300,000 people to start using this form of transport once the line is inaugurated. Today’s denotation is a historical moment and the Subway Line 4 will represent a very important legacy,” said Cabral. In all, more than 6,000 meters of tunnels of line have already been excavated (where the trains will pass) between Barra da Tijuca and Gávea.

Because the tunnels along the Barra da Tijuca-Gávea stretch pass inside the solid rock, the Construtor Rio Barra Consortium, responsible for the construction work between Barra da Tijuca and Gávea, adopted the New Austrian Tunneling Method (NATM) - Drill and Blast technology to build it. NATM involves controlled detonations and is considered the ideal method for excavations through rock.

"It is a highly complex project, since Rio de Janeiro is a densely population urban center,” said Lúcio Silvestre, Contract Director at the Construtor Rio Barra Consortium, formed by Odebrecht Infrastructure, Queiroz Galvão, Carioca, Cowan and Servix. “The construction methods used for the tunnels and stations were chosen considering the lowest impact to the surrounding area and the fastest construction time,” he explained.

Starting in 2016, the Subway Line 4 will connect Barra da Tijuca to Ipanema in just 15 minutes and the Barra da Tijuca-São Conrado tunnel will connect the two most highly used stations along the Subway Line 4: Jardim Oceânico, with 91,000 passengers per day, and São Conrado, with 61,000. The Barra-São Conrado route will be completed in less than six minutes.

Water is 100% Reused in the Line 4 Construction Work

The Construtor Rio Barra Consortium makes efforts to reduce the environmental impact of the construction work, as well as the impacts affecting the community. In Barra da Tijuca and São Conrado, workers installed treatment plants that reuse all of the water produced by the tunnel and station excavations. Since the start of the construction work, more than 90 million liters have already been reused.

There is permanent environmental monitoring, such as the noise levels, vibrations and air quality in the areas of influence. At the support sites or the work fronts, daily actions become an example of environmental responsibility. In Barra da Tijuca, for example, rare specimens of bromeliads were carefully removed from the slope of Morro do Focinho do Cavalo and transplanted at the Rio de Janeiro Botanical Gardens.

More than 300,000 People will Use the Subway Line 4 Every Day

The Rio de Janeiro Subway Line 4 will transport more than 300,000 people per day starting in 2016 and will remove some 2,000 vehicles per peak hour from the streets. With the new line, passengers will be able to use the city’s entire subway system by paying only a single fare.

There will be six stations (Jardim Oceânico, São Conrado, Gávea, Antero de Quental, Jardim de Alah and Nossa Senhora da Paz) along the approximately 16-kilometer extension. The Subway Line 4 will begin operating during the first half of 2016 after undergoing a test phase.