Offshore platform and method for its installation

A concrete platform for use in offshore drilling and the like, comprising a superstructure and a base structure, said superstructure including a deck and supporting towers, said base structure including a base raft and caissons, said caissons extending downwardly from the base raft to be embedded in the soil of the sea floor layer whereby external horizontal forces acting on the platform are opposed by soil pressure acting laterally on the sunken portions of the caissons, energy absorbing means interconnecting said caissons and said base raft, said energy absorbing means including (a) members which are relatively rigid under wave forces but which fail under strong earthquake and (b) an energy-absorbing resilient (elastic) material.