Wave Reflection: Small and Large Scale Experiments on Wave Absorbing Quay Walls C. Altomare Postdoctoral Researcher, Flanders Hydraulics Research, Antwerp, BELGIUM X. Gironella Associate Professor, Maritime Engineering Laboratory, Universitat Politècnica de Catalunya, Barcelona, SPAIN J. Sospedra Laboratory Manager, Maritime Engineering Laboratory, Universitat Politècnica de Catalunya, Barcelona, SPAIN Summary The paper reports on small and large scale experiments carried out to assess the response of prefabricated caissons with internal rubble mound in terms of wave reflection. The research was conducted to analyse the effect of the model scale on the structural response and the treatment of the scale effects. Physical model tests were carried out in the small and large scale facilities at Universitat Politècnica de Catalunya, in Barcelona. The authors applied the Burcharth et al (1999) approach to treat scale effects and compared the results with the Matteotti’s ones (1991). Introduction Vertical quay walls are a widespread solution as berthing structures because they allow an optimized use of the port area with small occupancy. Notwithstanding, they reflect almost all the incident wave energy, thus their use is not advisable in port basins exposed to re-reflected waves. A solution based on less reflective structures would be advantageous. Non-conventional vertical structures can represent an alternative. Anti-reflection quays and dikes have been experimentally studied over the years (Jarlan 1961, 1965; Hattori 1972; Ijima et al. 1976; Matteotti 1991; Fugazza and Natale 1992; Tanimoto and Takahasi 1994; Chegini 1997; Suh et al. 2006; Huang 2007; Garrido et al. 2010, Taveira Pinto et al. 2011; Faraci et al. 2012). Figure 1. Scheme of the quay as in Matteotti (1991) This paper describes the reflection response of low-reflection vertical quays, whose upper wall, exposed to the incoming waves, is replaced by dissipative cells with rubble mound inside (Figure 1). The study aimed to characterize the influence of model scale and nominal diameter of the rubble