Prestressed structure

Claim 1

A SUBSTANTIALLY CYLINDRICAL PRESTRESSED METAL STRUCTURE COMPRISING AN ANNULAR SUBSTANTIALLY CYLINDRICAL SIDEWALL, A SERIES OF CONVOLUTIONS OF TENDONS HAVING HIGH TENSILE STRENGTH STEEL CORES WRAPPED ABOUT THE OUTER SURFACE OF THE WALL UNDER SUBSTANTIAL TENSION, SAID TENDONS ELONGATED A DESIRED AMOUNT TO DEVELOP A PREDETERMINED TENSILE STRESS THEREIN WHEREBY THE SIDEWALL IS PRESTRESSED AND CIRCUMFERENTIALLY COMPRESSED BY THE FORCE EXERTED BY THE ELONGATED TENDONS, SAID TENDONS INCLUDING A PREFORMED FLEXIBLE AND SCUFF AND ABRASIVE RESISTANT PLASTIC COATING COMPLETELY ENVELOPING THE CORE OF EACH TENDON AND APPLIED THEREON BEFORE SAID TENDONS ARE WRAPPED AND ELONGATED ABOUT THE SIDEWALL, A PORTION OF SAID PLASTIC COATING BEING POSITIONED BETWEEN THE OUTER SURFACE OF THE SIDEWALL AND THE STEEL CORES OF THE TENDONS, SAID PLASTIC MATERIAL OF SUFFICIENT THICKNESS AND POSSESSING SUFFICIENT RESISTANCE TO EXTRUSION TO RESIST THE RADIAL FORCE DEVELOPED BY THE TENSIONED TENDON WHEREBY THE TENDON REMAINS ENVELOPED IN THE PLASTIC COATING UNDER SAID RADIAL FORCE, AND A PLURALITY OF CLIP MEMBERS OVERLYING THE TENDONS AND JOINED TO THE SIDEWALL TO HOLD THE TENDONS IN POSITION AND CLOSE CONTACT WITH THE SIDEWALL WHEREBY THE CYLINDRICAL CONFIGURATION OF THE SIDEWALL MAY BE MAINTAINED.