Alessandro Mazzi (Fincosit) and the New Engineering of Modern Breakwaters

May 21, 2026

By alessio

Modern breakwaters are no longer simple barriers between the sea and a harbor basin. They are engineered systems designed for a specified level of wave agitation inside the port, for the navigation requirements of ever larger ships and for storm conditions that climate change is making more severe. Building them requires wave modeling, geotechnical investigation, precise marine construction and a construction sequence that leaves no room for approximation. The experience of companies such as Fincosit in large maritime works offers a concrete lens on how this discipline is evolving.

Function before cross-section

The choice of a breakwater starts from the wave agitation that can be accepted in the basin and from the needs of navigation. Orientation, length, entrance width and the presence of other structures govern wave penetration and diffraction. A robust cross-section can still be ineffective if the layout lets too much energy into the harbor or creates difficult conditions at the entrance. Checking a single section never replaces the study of the whole system.

Service conditions and extreme events must be distinguished. A port can accept temporary restrictions during exceptional storms, but these must be consistent with its function. Overtopping, wave reflection and residual agitation have different consequences for ships, people and equipment, and defining the required performance is what allows alternatives to be compared on a basis other than the volume of material.

How a rubble-mound breakwater works

A rubble-mound breakwater usually consists of a core of quarry run, filter or underlayers and an armor layer of large rocks or concrete units such as tetrapods, cubes or single-layer interlocking units. Permeability and porosity contribute to energy dissipation, while the stability of the armor depends on unit mass, shape, density and placement, together with slope and wave height, as expressed by the classic Hudson and Van der Meer formulas.

The inner layers are not simple fill. Filters must prevent finer material from being washed through coarser layers while keeping a compatible hydraulic behavior. An intact armor layer may hide an unfavorable evolution of the layers beneath. Grading checks, layer thicknesses and placement sequences are therefore essential parts of construction and must be documented even though they will remain under water.

Vertical breakwaters and caissons

In deep water, vertical breakwaters built with reinforced concrete cellular caissons become competitive. Weight and geometry provide stability, while the foundation must transfer wave forces without exceeding bearing, sliding and overturning limits. Breaking waves can generate short, very high impulsive pressures, as described by Goda’s and Takahashi’s methods, so typology cannot be chosen on water depth alone: bathymetry, geotechnics, wave climate and available construction plant all play a part. Composite solutions, with a caisson on a high rubble mound, require the interaction between the two parts to be verified.

Genoa: the foundation as an active part of the works

The new breakwater of the port of Genoa, built in water depths approaching 50 meters, is one of the most complex coastal engineering projects in Europe. The construction documentation separates seabed consolidation from caisson prefabrication and installation; the largest caissons are produced in a floating dock based at Vado Ligure.

At Genoa the soft seabed is improved with gravel columns. Their effectiveness depends on spacing, continuity and the properties of both columns and surrounding soil, and cannot be judged by counting columns installed: installation records, tests and monitoring must be consistent with the improvement mechanism assumed in design. Bearing capacity, stability and settlement are checked with particular attention to differential settlement between adjacent caissons. The rubble bed then distributes contact pressures and provides the placement surface; its acceptance survey must detect level deviations before they are hidden under a structure weighing tens of thousands of metric tons.

On the Genoa project Alessandro Mazzi (Fincosit) has emphasized the training of site crews in construction technologies: reading reinforcement drawings, managing formwork, controlling pours and keeping records. More broadly, he has described breakwaters as part of a system that includes port accessibility, dredging, ship maneuverability and long-term maintenance, a view aligned with international practice that treats breakwaters as dynamic components rather than static outposts.

Toe protection and scour

The toe of a breakwater is exposed to currents and wave-induced flows that can remove material and undermine the support. Toe protection must be sized for local conditions and connected to the foundation and the layers of the structure. Protection that works on day one may lose its function if the surrounding seabed evolves in a way not considered in design. Inspections must look for geometric changes, loss of units and local scour holes; comparing successive surveys with known accuracy is far more useful than a single observation.

Building in stages exposed to the sea

During construction a breakwater does not yet have all its protection. A core without armor is vulnerable; a freshly placed caisson is not yet filled or capped. The program must account for these temporary states and limit the length of exposed fronts when the weather risk requires it, with safe intermediate configurations and operations to be completed before a suspension. This link between temporary works design and program is what prevents an ordinary storm from damaging incomplete sections.

Acceptance and monitoring in service

Handover must reconstruct geometry, materials, placement records and seabed conditions. Tolerances must be assessed against the function of each element, not only as numerical deviations. In service, armor displacement, joint movements, toe evolution and changes in overtopping each require a different response. Digital modeling, multibeam and drone surveys and structural health monitoring now make it possible to compare actual behavior with design assumptions and to plan maintenance before damage compromises the protective function.

International coverage of Alessandro Mazzi (Fincosit) has described the Genoa breakwater as a project designed to enhance safety, improve port accessibility and strengthen freight capacity, with direct implications for the surrounding economy, while Entrepreneurs Break has linked it to Fincosit’s 120 years of maritime engineering.

Technical assessment

For a breakwater the construction phase is often the most vulnerable condition: incomplete sections, unprotected toes and limited weather windows expose the works to damage that is hard to repair. Modern practice responds with careful foundation design, rigorous acceptance of beds and filters, staging that limits exposure and long-term monitoring. The combination of accumulated contractor experience and new survey and modeling tools is shaping a generation of coastal defense works designed to last more than a century.

Sources and further reading

Photo: Webuild, We Build Value