Variability of wave impact measurements on vertical breakwaters

Abstract

The measurement of wave-induced impacts on structures involves significant scientific and engineering challenges. Regular nearly breaking pgbgand broken waves generated following cnoidal and first-order Stokes wavemaker theory have been considered to study the variability of wave impacts on vertical breakwaters. Four small-scale hydraulic experiments were carried out and repeated 120 times using high-speed pressure and force measurement equipment. High variability in the measured pressure field and total force were observed, reflecting the random nature of the studied phenomena. The force variability was similar for the nearly breaking and broken waves. The maximum measured force was between 166 and 177% of the minimum measured force. In relation to the force distribution and maximum pressure points, the observed variability is higher for broken waves. To deal with such variability in the observations, suitable probability distributions for forces (GEV) and pressures (Gamma) are proposed.

Effect of wave storm representation on damage measurements of breakwaters

“…Moreover, a pumping system allows the generation of currents in the flume. Since its inauguration in 2010, CIEMito has been successfully used for academic and scientific projects related to ocean engineering (e.g., Oliveira et al, 2012;Marzeddu et al, 2017).…”

“…Although small-scale models have been extensively used to study the hydraulic behavior of marine structures (Huges, 1993;Kirkegaard et al, 2011), there are several uncertainties related to their use. This includes uncertainties pertaining to scale effects (Heller, 2011;Lykke Andersen, 2006;Oumeraci, 1984), length of scale models (Reis et al, 2008;Romano et al, 2015), generation of extreme waves (Oliveira et al, 2017 and references cited therein) and test repeatability (Marzeddu et al, 2017), among others.…”

“…The hydraulic behavior of a rubble-mound breakwater depends on wave-structure interaction and block-block interaction processes, which are complex phenomena that can generate a turbulent environment close to the structure (Losada et al, 2005;Sierra et al, 2010). Then, unlike semi-empirical formulae which give deterministic outputs, results from physical experiments can present high variability associated to test repeatability (Marzeddu et al, 2017;Melby and Kobayashi, 1998;Stagonas et al, 2016;van Gent et al, 2018). To perform test repetitions, the reconstruction of the damaged breakwater is mandatory.…”

A computational framework for fluid–structure interaction with applications on stability evaluation of breakwater under combined tsunami–earthquake activity

“…First, impact force caused by a tsunami wave is one of the main factors that damages coastal breakwaters. When tsunami waves impact a breakwater, a huge impact force can act on a caisson, in addition to the static load induced by water‐level difference (Marzeddu et al., 2017). Second, water‐level difference on both sides of the caisson results in a lateral force and overturning moment on breakwater, leading to sliding failure and overturning failure (Arikawa et al., 2012).…”

Experimental Study on the Probability of Different Wave Impact Types on a Vertical Wall with Horizontal Slab by Separation of Quasi-static Wave Impacts

“…For the vertical structures, incoming wave shapes and breaking conditions play a dominant role in determining the wave impact [8][9][10], with the maximum wave load mostly associated with the thin air layer between the wave front and the structural surface, called flip-through, specifically [11][12][13]. It has also been found that the largest local wave impacts usually occur at positions near the still water level [14][15][16][17]. To date, the most widely recognized empirical formula to predict wave loads on vertical wall is from study by Goda [18], which has been widely applied to ocean engineering applications.…”