How does the immersed tunnel technology work, which will be used in Santos
The tunnel between Santos and Guarujá, on the coast of São Paulo, a long-discussed infrastructure project for nearly a century, is finally expected to start taking shape next year. In August, an auction will determine which construction companies will build and operate the project, which will use an unprecedented technology in Brazil: the immersed tunnel.
Here’s how it works: instead of digging the tunnel under the seabed, it is first built on the surface in reinforced concrete sections. These sections are then temporarily sealed, towed to the desired location, submerged to the seabed, and connected. Afterward, the interior is finished, and the tunnel is ready.
Since such a project has never been done in Brazil, authorities have traveled abroad to attract companies that master this technology to participate in the bidding. One of the sites visited is the construction site of the Fehmarnbelt Tunnel, an immersed tunnel being built between Germany and Denmark.
In April, a mission composed of the Minister of Ports and Airports, Silvio Costa Filho, and the Governor of São Paulo, Tarcísio de Freitas, visited the Fehmarnbelt Tunnel and other European sites. "It’s the same technology that will be used in the Santos tunnel," said Costa Filho. Tarcísio described it as “an example so we can deliver the best for the people of Baixada Santista.”
“We came to learn best practices. It’s important to share this experience to carry out the tunnel between Santos and Guarujá, which Brazil has been waiting for over a century,” federal deputy Paulo Alexandre Barbosa (PSDB-SP), president of the FPPA and former mayor of Santos, told DW. Authorities also met with representatives of companies involved in the project.
The auction is scheduled for August 1st, and according to reports in the Brazilian press, four consortia are currently interested: Mota-Engil (Portugal) with CCCC (China), Acciona (Spain) with Ballast Nedam (Netherlands), Andrade Gutierrez (Brazil) with Webuild (Italy), and OEC (Brazil) with EGTC (Brazil) and a third company.
One of the companies visited by Brazilian authorities was the Dutch firm Tec Tunnel, involved in the Fehmarnbelt project and other similar projects worldwide. The Chinese company CCCC built the Taihu underwater tunnel, the largest in China at 10.8 kilometers long, and the Dutch Ballast Nedam has built similar tunnels in the Netherlands and is currently constructing one in Iraq.
Source: G1
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