RESPONSE OF DRYDOCK GATES TO BLAST LOADING.
Final rept., 15 Feb-15 Oct 66,
MACNEAL-SCHWENDLER CORP SAN MARINO CALIF
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Relatively simple methods of predicting the response of the primary structure of drydock closures for damage assessment purposes were developed in this study. It was found that the lowest natural mode is the principal contributor to deflections and stresses as long as the dynamic loads are applied simultaneously to all parts of the gate. Static analyses were made for uniform and hydrostatic loads, and transient analyses were made for simple blast pulses and uniform step-function loads. Two modal analyses were also made. It was found that the static deflection shapes are very similar to the first natural mode shape, and can be used as such for the accuracy required for damage assessment. Only the virtual mass of the water, the concrete ballast, and the water ballast are important for determining the appropriate mass parameter for a drydock gate. It was found that the peak stresses due to a suddenly applied uniform pressure of the same magnitude as the hydrostatic pressure at the bottom of the gate are about 6 times higher than those due to the hydrostatic pressure for which the gate presumably has been designed. It is apparent that additional study is needed to define the nuclear environment for drydock gates, since it is not clear as to which phenomenon is the principal threat. Author
- Marine Engineering