Marine structure having a deck or work platform supported by absorbing mechanisms

Claim 1

A marine offshore structure for compensating for seismic shocks comprising: (a) an exterior truss structure having its base anchored to the subsurface floor; (b) a marine deck or work platform within said truss structure; (c) a plurality of vertical structural members interconnecting said truss structure and said deck or working platform for suspending said deck or work platform from said truss structure, said vertical structural members being flexible along their respective length to permit horizontal movement of said truss structure relative to said deck or work platform; (d) means for mitigating the effects of seismic shocks on said deck or work platform, including at least one first nonlinear shock absorber means coupled laterally in a first horizontal direction between said deck or work platform and said truss structure for damping horizontal seismic forces in said first direction between said deck or work platform and said truss structure, said first nonlinear shock absorber means being substantially rigid to provide stiff damping of relatively low amplitude seismic forces and providing substantially less rigid damping during relatively high amplitude seismic forces; and at least one second nonlinear shock absorber means coupled laterally in a second horizontal direction, substantially orthogonal to said first direction, between said deck or work platform and said truss structure for damping horizontal seismic forces in said second direction between said deck or work platform and said truss structure, said second nonlinear shock absorber means being substantially rigid to provide stiff damping of relatively low amplitude seismic shocks and providing substantially less damping during relatively high amplitude seismic forces, whereby said deck or work platform is able to move relatively freely in horizontal directios when it is subjected to relatively severe seismic shocks.