The subject matter of the invention is a gravity structure intended for a marine civil-engineering construction, comprising a slab configured so as to be placed on a sea bed and secured to a shaft directed in a principal direction substantially orthogonal to said slab, characterized in that the gravity structure comprises at least one anchoring tie rod extending in said shaft and in the slab, the gravity structure being configured so that, in a service position of the gravity structure, said at least one anchoring tie rod is anchored in the sea bed.