engleski

Smanjenje opterećenja perforiranog obalnog zida primjenom uronjenog valoloma

Perforated seawall could reduce significant wave heights in front of the seawall up to 20% in comparison with the classical solid seawall, but only for the specific relationship between wave parameters and seawall geometry. If the seawall is defended by the smooth submerged breakwater, this reduction could be up to 50%, in joint action. Combination of the perforated seawall and sub-merged breakwater (low crested structure-LCS) is a special type of the coastal defence structure which achieves great reduction of incoming wave energy. At the other hand, smooth submerged LCS reduces loads on the perforated seawall what has favorable effects on the final costs. Reduction of wave load on perforated seawall when submerged smooth LCS is placed in front of it is investigated in this work. The interaction of the smooth submerged LCS and perforated seawall was investigated in labora-tory wave channel. Two experimental models were used, first includes loads on perforated seawall, and second loads on perforated seawall defended by submerged LCS. It is studied how the LCS impacts on the wave load value of the perforated seawall. Pressures were measured at the front (perforated) and rear (solid) wall of the perforated chamber. Calculation of the horizontal forces from measured pressures was conducted, for each front and rear wall. It was concluded that submerged LCS decreases forces on front and rear wall of the perforated seawall in dependence of LCS crown submersion and the force reduction on the front wall achieves ≈15÷25%, and on the rear wall ≈25÷40%. Also, mathematical model was formed for pressures calculation on the front and rear walls. Model was obtained assembling two mathematical models: empirical model for calculation of wave height transmission across submerged breakwater and semi-empirical model for wave load calculation on the perforated seawall. Comparison of calculated and measured forces gives that calculated forces are in average 5% greater than measured for front wall, and 29 % for rear wall. These results are conservative what was acceptable for engineering practice.

smooth submerged breakwater; perforated seawall; perforated seawall loads; force reduction

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