An experimental study of partly/hardly reshaping mass-armored double-berm breakwaters

Abstract

A 2D experimental modeling of hardly/partly reshaping mono and double-berm breakwaters is carried out in the wave flume by using irregular waves with the JONSWAP spectrum. A more stable structure with higher hardly reshaping performance is provided by using a second berm below SWL, as the wave breaker type changed from surging into plunging. In this paper, the effects of some sea state conditions, and structural parameters on the eroded area have been studied. The findings reveal that as the wave height, the wave period, the water depth, the first berm elevation from SWL, and the water depth over the second berm increase, the eroded area made in the first berm increases. On the other hand, by increasing the first and second berm widths, and the slope angle over the second berm, less damage occurred. In consideration of the second berm characteristics such as berm width, water depth over the second berm, and the slope angle, an equivalent slope, i.e., an equivalent Iribarren number, is defined for the double-berm structure. Eventually, concerning the defined equivalent slope, new stability formulae are proposed to estimate damage parameter in both mono and double-berm breakwaters.