Catania Harbor Breakwater: Physical Modelling of the Upgraded Structure

Abstract

Most of the worldwide historical coastal and harbor structures have been severely damaged by extreme sea storms during their lifetime and hence need to be upgraded, also considering the effects of climate change (Hughes, 2014). Physical modelling is identified as the only feasible approach for the optimization of the upgraded structures, because of the existence of few studies concerning such an issue and the lack of specific design formulae (Burcharth et al. 2014; Croeneveld et al. 1984; Lara et al. 2019; Foti et al. 2020). Therefore, a novel general methodology for the design of upgrading solutions for existing breakwaters based on physical modelling is presented, considering the case study of the Catania Harbor breakwater. The results of the systematic extensive experimental campaign on possible solutions for upgrading the Catania harbor breakwater led to some general practical findings, which can be useful for the design of restoration options for existing breakwater at end of their lifetime.

Influence of Van Gent Parameters on the Overtopping Discharge of a Rubble Mound Breakwater

“…Figure 3 shows the value of q * against the ratio between the height of the structure above the mean water level (R c ) and the significant wave height (H s ). The non-dimensional mean overtopping discharge is shown for all the values of β considered in the numerical model and for all the physical model tests carried out by Stagnitti et al [16]. The physical model tests considered 5 different wave conditions, including the 100 years return period used in the numerical model, and each wave condition was tested three times [16].…”

“…In the present work, a damaged cross-section of the Catania harbor breakwater (Sicily, Italy) was analysed using a bidimensional macroscopic VARANS numerical model. The model was implemented in the software OpenFOAM (v1806), where the solver ihFoamV1 was used, and it was validated by comparison with the results of physical model tests carried out by Stagnitti et al [16,17]. Nine simulations were carried out, each one with a different value of the turbulent friction parameter β assigned to the armor layer of the structure, and the overtopping discharge was calculated in each simulation.…”

Assessment of the Failure Probability of Upgraded Rubble-Mound Breakwaters

“…Instead, the standard deviation of the Normal distribution of ℎ 𝑤𝑎𝑙𝑙 was set following the indications of Lara et al (2019). The employed values of 𝑓, 𝑎 and 𝑏 are not only the ones indicated by van der Meer (1988a) and EurOtop ( 2018), but also the sitespecific ones deduced from the results of the previously carried out composite modeling of the upgraded Catania harbor breakwater (Stagnitti et al, 2020(Stagnitti et al, , 2022(Stagnitti et al, , 2023. In particular, site-specific values of 𝑓 were calculated for the cases showed in Fig.…”

Assessment of the variation of failure probability of upgraded rubble-mound breakwaters due to climate change

“…The extra armor units can be placed according to a regular design slope or following the irregularities of the existing structure through the construction of a single or double layer, with a toe berm to ensure their stability. In particular, the following six configurations have been verified through the performance of physical and numerical tests (Stagnitti et al, 2020;Stagnitti et al, 2022): 1. configuration E, which is the existing structure whose wave wall height is +8.50 m above mean sea level (see Figure 3A); 2. configuration EM, which consists in the simple heightening of the wave wall up to +9.50 m above mean sea level (see Figure 3B); 3. configuration AS, which consists in the armor layer restoration with 30 t Antifer according to the design slope of 1:2 (see Figure 3C); 4. configuration AD, which consists in the addition of a double layer of 30 t Antifer smaller than the existing ones, following the irregularities of the present armor layer (see Figure 3D); 5. configuration CM, which involves the addition of a single layer of 62 t cubes equal to the existing ones, following the irregularities of the present armor layer (see Figure 3E); 6. configuration CS, which consists in the raising of the wave wall up to +9.50 m above mean sea level and the addition of a single layer of 62 t cubes equal to the existing ones according to the design slope of 1:2, after the regularization of the present armor layer (see Figure 3F).…”

“…The experimental campaign was carried out at the Hydraulic Laboratory of the University of Catania (Stagnitti et al, 2020;Stagnitti et al, 2022). A total of 192 two-dimensional physical model tests were performed at 1:70 scale inside a flume 18.00 m long, 1.20 m high and 2.40 m wide, built within a tank equipped with a flap-type wavemaker for the generation of random waves using JONSWAP spectra.…”