Sea platforms to support industrial installations

摘要

A marine platform supports industrial installations. The platform comprises a barge and a lower keel on which the barge rests. The keel is positioned on the ocean floor. Intermediate friction elements are situated between the contact surfaces of the barge and the keel. Elastic elements are interconnected to the barge and the keel. These elastic elements oppose displacements between the barge and the keel. The displacements are controlled because the friction resulting from the intermediate friction elements impedes movements between the barge and the keel. These movements may be caused by external forces acting on the barge, such as waves, currents, and winds, or may be caused by the effects of acceleration on the keel induced by an earthquake of small magnitude. The intermediate friction elements have means for permitting displacements between the barge and the keel in the case of an earthquake of great magnitude. The elastic elements have means for decreasing an elasticity constant in discrete degrees when the displacements surpass a predetermined value so that, as the intensity of the earthquake increases, the oscillation period of the barge on the keel increases too but amplication of the oscillation period is avoided.