Storm damages Genoa breakwater caisson; repairs underway
A severe storm in the Ligurian Sea, with waves reaching 7 m, has partially damaged the fifth caisson of Genoa's new breakwater during filling operations.The PerGenova Breakwater consortium, led by Webuild and including Fincantieri Infrastructure Opere Marittime, Fincosit, and Sidra, reports that the damage is confined to the upper section of the caisson and does not affect its structural integrity. Repair work is already in progress and is not expected to impact the project's timeline.
The New Genoa Breakwater project, commissioned by the Western Ligurian Sea Port Authority, aims to enhance the port's capacity to accommodate larger vessels. The breakwater will extend approximately 6 km and rest on seabeds up to 50 m deep, making it one of Europe's most significant maritime infrastructure projects. Each caisson measures up to 33 m in height, 35 m in width, and 67 m in length, comparable to a 10-storey building. Construction began in May 2024 with the installation of the first of over 90 caissons. The project commenced in February 2023 and is projected to be completed by November 2026.
Phase A involves installing approximately seven million tonnes of rock at depths of up to 50 m to form the breakwater's foundation, which will support around 100 prefabricated reinforced concrete caissons. The project is co-funded by the Italian government, with €600 million (approximately £517 million) allocated from the Recovery and Resilience Facility Complementary Fund and the Port Infrastructure Fund. The overall project is valued at €928 million (approximately £800 million) and is expected to employ over 1,000 people during its construction.
The new breakwater is designed to provide ships with direct access to terminal facilities and includes a wide turning basin to accommodate ultra-large vessels, enhancing the port's competitiveness. The consortium's continuous monitoring enables prompt responses to challenges posed by complex engineering requirements and adverse weather conditions.
In a statement, WeBuild said: "Our constant monitoring activity allows us to promptly intervene, meeting and exceeding complexities linked to building such a challenging work from an engineering perspective and due to the weather and sea conditions in which the work is being built."
Caisson construction
The process of constructing the 35 x 37 x 67 m caissons stands as one of the most intricate elements of the entire project, typically taking about 20 days and involving around 50 workers.
Carried out directly at sea, the first step involves positioning the metal formwork onto a floating platform. This formwork mirrors the exact dimensions of the caisson being constructed. The necessary systems for spacing and the metal reinforcement cage are placed, followed by the initial pour of concrete. Once this layer solidifies, the formwork is raised slightly, and the process is repeated until the desired height is achieved.
When the caisson reaches its full height, it’s tugged into its designated spot by powerful tugboats. To sink it into place, water is poured into the cells, causing the caisson to descend until it settles on the seabed. Once positioned, the cells are filled with rock material for added stability.
Further work takes place at sea, where the caisson is sealed with a superstructure to support the seawall—the most prominent part of the breakwater, designed to lessen the impact of crashing waves.
Sustainability is key throughout this process. A specially developed concrete mix is used to ensure enhanced waterproofing, while the interior of the caisson is filled with recycled inert materials, including debris from the demolition of the previous breakwater.
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