Surface roughness effect of vertical and sloped seawalls in incident random wave fields

Experimental investigations on wave reflections, run-up and run-down, and wave pressures on plane, dentated and serrated seawalls were carried out in random wave fields for a wide range of wave heights, wave periods, seawall slopes in a constant water depth of 0.7 m. Based on the measurements, predictive equations are proposed which can be used for practical purposes. A total performance evaluation is carried out on the plane, dentated and serrated seawalls. The improved performance (reduction of wave reflection, run-up and run-down and wave pressures) of the serrated seawall is elucidated. The serrated seawall is about 20-40% better than a plane seawall for reducing wave reflections, run-up and run-down. The results can be used for a better hydrodynamic design of vertical structures (quay walls in harbors, vertical seawalls, caisson type breakwaters) and sloped structures (seawalls, dikes, wave absorbers in the laboratory).