Webuild: seabed consolidation completed for New Genoa Breakwater

Completion of critical phase for construction of breakwater involving consolidation of nearly 300,000 square metres of seabed

Work will remain invisible but remains crucial for stability of future breakwater

With installation of latest caisson, breakwater exceeds 1,700 metres in length

Construction site employs about 800 people and involves over 400 companies in supply chain

MILAN, November 11, 2026 –   With an underground grid of approximately 67,300 gravel columns designed to stabilise nearly 300,000 square metres of seabed, the foundation for the New Genoa Breakwater is ready: the PerGenova Breakwater Consortium, led by Webuild and operating on behalf of the Port System Authority of the Western Ligurian Sea, has completed the ground preparation for the port infrastructure.

This work represents a fundamental structural component — invisible but essential — for ensuring the geotechnical stability of the future breakwater. The completion of this phase highlights the extraordinary engineering complexity of the project, which required advanced technical solutions and highly specialised underwater operations to create a structure capable of providing the seabed with the necessary load-bearing capacity and supporting the entire infrastructure.

The approximately 67,300 gravel columns will help improve the geotechnical properties of the soil and make it suitable for supporting the new infrastructure. In total, over 722 linear kilometres of columns were constructed using the “Wet Top Feed” method, which involves the use of special vibrating probes called vibroflots that penetrate the seabed and position and compact the granular material to the specified depth, forming actual underground columns that stabilize the soil.

The project required the use of approximately 2.8 million metric tons of gravel, spread over an area of nearly 300,000 square metres — equivalent to more than 40 soccer fields. After the gravel was laid, work proceeded with the installation of the columns using a vibroflot. The columns, which have a minimum diametre of 110 centimetres and a length ranging from 6 to 13.5 metres, form a network of reinforcement elements that prepares the seabed to safely support the new offshore structure.

The work was carried out in the open sea, with the support of three specialised pontoons and eight cranes operating simultaneously, 24 hours a day. The construction site is also a major source of skilled jobs for the local area and the country: approximately 800 people are employed on-site, and over 400 direct suppliers are involved. Expertise, equipment, and skilled labour are all being made available for the country’s major infrastructure projects.

At the same time, construction of the breakwater proceeds uninterrupted: with the latest caisson installed, the total length has exceeded 1,700 metres, the result of a well-structured and coordinated project organisation capable of addressing the technical and environmental complexities of one of the most important maritime construction sites in Europe.