Structural Design of a Pile-Supported Reinforced Concrete Launch Slab for Heavy Off-Shore Operations at the Port of Ravenna

This thesis presents the structural design of a pile-supported reinforced concrete launch slab at the Porto San Vitale waterfront, Marina di Ravenna, commissioned by Rosetti Marino S.p.A. The structure — the platea di varo — is the transfer surface for large prefabricated steel modules during their launch from yard to pontoon. The governing load case is the launch itself: vertical line loads of 2880 kN/m on two contact strips spaced 18.0 m apart, producing a total vertical resultant of 72,000 kN, with a simultaneous horizontal drag of 12,000 kN. The site is underlain by coastal sands classified as NTC 2018 soil category D (Vs,30 = 178 m/s), with a shallow water table at 1.75 m depth and zones of liquefiable sand extending to approximately 9.5 m, identified by piezocone testing in May 2025. The foundation consists of 50 displacement piles, 700 mm in diameter and 40 m long, installed by the Soles method, founding below the liquefiable layer in the deeper competent deposits. The slab is modelled as a plate on a combined Winkler-pile spring system and analysed under two bounding assumptions — continuous soil contact and no soil contact — with design values taken as the average of the two. All verifications follow NTC 2018 and Circular 7/2019 under Approach 2 (A1+M1+R3). The seismic design obligation is limited to the liquefaction assessment; no structural seismic verification applies. Materials are concrete C35/45 and steel B450C, with 50 mm cover for XS2 marine exposure. Calculations were performed in SISMICAD 12.24 with selected independent hand checks.