Author(s): T. H. G. Jongeling; N. H. Rovekamp
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Keywords: Inflatable surge barrier. Rubber dam. Bottom recess. Air-and water filleddam. Inflation and deflation process. Sheet guiding rollers. Wave loads. Wave-induced response. Clamping forces. Sloshing. Scale model. Air compressibility. Sheet properties
Abstract: A flood-protective barrier, consisting of three inflatable rubber dams, has been designed in the delta of the river IJssel, Netherlands. The rubber dams with height of8. 5 m, rest in recesses in a concrete sill, when not in use. They are inflated when a severe storm occurs and the alarm water level is exceeded. The rubber dams are partly filled with water; the remaining part above the free water surface is filled with air. Several new elements in the design, the use of the dams as flood-protective barriers and the scaling up compared to existing dams necessitated a study in a scale model. In particular, the response of the dam on wave loads and in connection herewith the possibility of sloshing in the dam had to be investigated. Special attention was paid to a correct scaling of both the stiffness of the air in the dam and the over-pressure related to the atmospheric pressure. The tests revealed that the dam response was predominantly in a swaying mode with frequency equal to the wave frequency. A‘pulsating’mode with about a twice as high frequency was also observed, which mainly occurred after the passage of an over-topping wave. Important sloshing phenomena did not develop in the dam. Both the over-pressure in the dam and the tension stiffness of the sheet appeared to be important parameters in the response of the dam.
Year: 1999