Author(s): K. Al-Banaa; S. Neelamani
Linked Author(s): Khaled Al-Banaa, Neelamani Subramani
Keywords: Offshore breakwater; Overtopping; Low Astronomical Tide; High Astronomical Tide; Rocking of Units
Abstract: An offshore breakwater with single layer armor unit was proposed to protect an artificial promenade beach from erosion of waves, as a part of Al-Khiran pearl city development project in Kuwait. The stability and hydrodynamic characteristics of this breakwater is essential for understanding its functional performance and life time stability. A detailed physical model study using a 1:22.5 scale model was carried out. The physical model study was carried out for different water levels (Low Astronomical Tide (LAT), High Astronomical Tide (HAT) and water level at the crest of the breakwater (CAT) ). Waves with 80%, 100% and 120% of the design levels were generated. During the entire stability test, the designed structure was stable and showed enough reserve strength, except rocking and realignment of few rows of Seabee units on the seaside and closer to the crest level. Few inner layer stones around the seaside crest level were rocking and plucking for the design condition. Enough precaution need to be taken during construction to reinforce the inner layer materials and also for maintenance in future. The seaside toe mat material need to be designed for water particle velocity of 1.5 m/sec. The toe mat materials were rocking, moving and filling the Seabee central holes. The leeside armor units, on the other hand, were completely stable. The wave transmission is insignificant for LAT condition, but for HAT condition, the transmission coefficient varied from 0.12 to 0.165. The average significant wave height at the crest level in the breakwater is only in the order of 0.013 to 0.19 times the incident wave height for LAT condition and for HAT, it has reached to the order of 0.35. Overtopping of waves is dominant for HAT condition. The average energy dissipation coefficient of this breakwater is in the order of 0.8 to 0.85 for LAT and HAT conditions. The average wave reflection coefficient is 0.6, 0.5 for LAT and HAT conditions respectively
Year: 2010