2020 Volume 76 Issue 2 Pages I_168-I_173
Permeable wave barriers consisting of perforated metal plates and supportive pillars are placed on coastal revetment to mitigate wave splash and spray overtopping induced by storm surges and high waves. This study examined mitigation effects of perforated barriers on wave overtopping and wave forces to evaluate the hydraulic performance of perforated barriers under a wide range of relative crest freeboard corresponding to various site-conditions. Laboratory experiments of wave barriers mounted on vertical seawall and wave-dissipating seawall were carried out to investigate characteristics of maximum wave force acting on the barrier and mean wave overtopping rate. The experimental results indicated that the perforated barrier with a porosity of 30 % reduced the wave force acting on the barrier by at least 30 % when the seawall crest freeboard relative to wave height was ranging between 0.3 and 0.9 (i.e. low-crested seawall). The wave overtopping rate of the barrier decreased by 40 – 60 % in the case of low-crested seawalls. In the case of wave-dissipating seawall on steep sea bottom, the mitigation effects of the barrier on wave overtopping rate and wave force varied due relative positional relationship between wave breaking point and wave-dissipating blocks.
