Combining vertical and sloping structures in marinas: roundheads and perforated quaywalls

The unconventional inclusion of monolithic vertical type structures as well as traditional rubble mounds in shallow water yacht harbours can pose interesting challenges for both design and construction of breakwaters and quay walls. This paper describes the design, construction and post-construction aspects of two recent microtidal projects in western Italy, located at the mouth of the river Arno (Boccadarno at Marina di Pisa) and of the drainage channel Rio Martino (Latina, near Rome). The vertical structures made at the shallow roundheads with either reinforced concrete caissons or a crown of micropiles improve the stability, the navigational safety and the wave attenuation in the harbour basins, as compared to traditional rubble mounds, despite the more complex singularity. The vulnerable transitions (due to complex localized hydrodynamics) need specific three-dimensional model testing and preliminary oversizing of the sloping armour.