SPHERICAL JOINTS FOR CONNECTING UNDER-WATER FOUNDATIONS TO PLATFORM-SUPPORTING TOWERS

摘要

A joint connection between a concrete tower supporting a surface platform and a sea anchorage or foundation, comprises, an outer hemispherical socket shell which is adapted to be secured to the concrete tower and an inner head which has a hemispherical shell portion within the outer shell portion and a lower cylindrical portion which extends downwardly therefrom and is secured to a foundation plate having an opening therethrough for the passage of conveying lines. Lubricated slide shoe elements are disposed between the inner and outer shells to facilitate their pivotal interengagement. A support gimbal is secured within the inner head and a pull rod is connected to the gimbal and extends upwardly through the head and the outer shell and is connected to a beam mounted on the concrete foundation above hydraulic presses. The hydraulic presses comprise prestressing means connected to the pull rod to prestress it in a direction to urge the inner and outer shells into pivotal interengagement. The construction includes a bellows-like apron stretched between the outer shell and the baseplate as well as an outer tire-like apron engaged between the outer shell and the baseplate so as to define two annular inner spaces around the inner shell to seal the joint against sea contamination. Sealing liquid may be supplied into each annular space and to the lubricating shoes.