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Giant concrete structures were taken to the Atlantic to form a maritime barrier of kilometers on the coast of Rio de Janeiro, in a project that involved steel, concrete, floating technology, and a dock described as the largest in the world in its category.
Brazil erected one of the most imposing maritime structures of its port infrastructure by installing 42 floating concrete caissons in the Atlantic, used to form part of the protection system of the Port of Açu, on the northern coast of Rio de Janeiro.
To enable this barrier, the project used Kugira technology, described by Acciona as the largest floating caisson dock in the world, resulting in more than 3.8 kilometers of breakwater.
Of this total, 2.8 kilometers were artificially constructed with concrete blocks, forming a maritime protection designed to reduce wave force and enhance the safety of port operations in an area exposed to the ocean.
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New York removed the tracks from over 2,500 subway cars and dumped everything at the bottom of the Atlantic, and what seemed like trash turned into an artificial reef teeming with fish and divers.
Large pre-molded structures were placed in the sea to compose dikes capable of protecting port accesses and creating operational conditions for an industrial complex focused on cargo, energy, and logistical support.
According to Acciona, responsible for the project’s technical information, the terminal was the first built in Brazil with pre-molded concrete caissons applied to this type of solution in port infrastructure.
Port of Açu received concrete caissons in the Atlantic
The scale of the construction is evident in the volumes reported by the company, which indicates the use of 21 thousand tons of steel, 350 thousand cubic meters of concrete, and 42 floating caissons manufactured through Kugira technology.
Exclusively mobilized for the project, the dock allowed for the production of large concrete pieces that later became part of the port’s maritime protection, functioning as modules of a barrier installed in the Atlantic.
In São João da Barra, in northern Rio de Janeiro, the Port of Açu was designed to operate as a large industrial and port complex, with activities related to maritime logistics, energy, and support for offshore operations.
The position on the coast of Rio de Janeiro favors connection with strategic sectors, especially being close to significant areas for oil and gas exploration in the country, as well as maritime routes used by large vessels.
How the megacaissons form a maritime barrier
Among the most visual elements of engineering are the concrete caissons, structures that function as enormous pre-molded modules, produced in a controlled environment and then positioned in the sea to form sections of the dikes.
Aligned over the area planned in the project, these blocks create a physical barrier capable of reducing the action of the waves and protecting the internal zone of the port, where docking, vessel circulation, and cargo movement occur.
The technology applied at Açu draws attention by replacing part of a traditional model of breakwater construction, usually based on the intensive use of riprap, with a large volume of stones to form coastal barriers.
According to Acciona, the adoption of concrete caissons reduced the need for stones in the rock landfill by 8.5 million tons, in addition to avoiding the emission of 100 tons of CO2 during construction.
Kugira was used as a floating caisson factory
The central point of the operation, the Kugira functioned as a maritime factory prepared to produce large concrete caissons in sequence, allowing large-volume pieces to be manufactured close to the installation area.
Instead of relying solely on structures made on land and transported over long distances, this technology allows the assembly of blocks in a floating environment, which helps to enable large-scale port works.
At the Port of Açu, the arrival of the Kugira marked the first use of the technology in Brazil, according to Acciona, which highlights the dock as an essential piece for the production of the caissons used in the dikes.
With this structure, it was possible to construct 2.8 kilometers of artificial dikes made with concrete caissons, combining floating production, reinforced concrete, and maritime installation in a highly complex port engineering work.
Dike of more than 3.8 km protects the terminal
The main function of the dikes is to protect the terminal against the force of the sea, especially in a region exposed to the open ocean, where waves and maritime conditions can directly affect port operations.
In ports of this type, a maritime barrier reduces the energy of the waves before they reach the internal areas, creating a more controlled environment for maneuvers, docking, and cargo movement.
At Açu, the caissons help form a line of defense that separates the port area from the harsher conditions of the Atlantic, allowing the complex to operate with greater stability within the created protection.
This structure also shows how modern ports depend on increasingly larger works to accommodate vessels, specialized terminals, and industrial chains connected to global trade, especially in areas linked to energy and logistics.
More than just a physical protection, a breakwater over 3.8 kilometers redefines the maritime environment around the port and creates a zone prepared for operations that require stability, depth, and safe access.
Port Engineering Advanced on the Fluminense Coast
Acciona reports that its engineering area developed the basic project, the construction project, and provided technical assistance during execution, reinforcing the company’s role in the central stages of the work.
The company classifies the use of caissons as a pioneering initiative in Latin America for the construction of breakwaters aimed at the access of the shipyard and terminal at the Port of Açu.
Although the complex is known for its industrial scale, some of the most impressive engineering is hidden below the waterline, where the caissons perform a function similar to that of a submerged wall.
The 42 caissons do not appear as buildings in the urban landscape, but were installed to contain the ocean’s force and allow port operations to advance in an open sea area.
The use of concrete in floating modules also highlights the difference between land and maritime works, as at sea, each stage depends on stability, flotation, positioning, depth, and control of ocean conditions.
On the Fluminense coast, this solution allowed the creation of maritime protection formed by gigantic pieces and a system of kilometers-long dikes, combining steel, concrete, and floating technology.
The area exposed to the Atlantic now has a structure prepared to receive large-scale port operations, supported by precast caissons produced in a specialized dock and integrated into the final design of the port.
The Açu project reinforces the use of increasingly larger precast structures in coastal and port works, replacing part of the construction based solely on rocks with concrete caissons installed at sea.
How many other giant structures remain hidden at the bottom of the sea supporting ports, terminals, and trade routes without most people knowing?
