Adaptable to a variety of structures, un-bonded mono-strand post-tensioning can be easily, rapidly, and economically installed. Concrete construction applications for mono-strand systems include elevated slabs, slab-on-grade, beams, and transfer girders, joists, shear walls, and mat foundations.
Trans Fast Post Tension & Prestressed Concrete’s mono-strand post-tensioning systems use 0.5″ and 0.6″ diameter strands coated with a layer of specially formulated grease with an outer layer of seamless plastic extruded in one continuous operation to provide protection against corrosion. Each tendon is precisely coiled, cut, labelled, color-coded, and delivered to the construction site. A wide variety of anchorage systems are available to meet design specifications.
Encapsulated un-bonded mono-strand post-tensioning systems are used in areas that are subject to corrosive conditions. Strands are protected at the anchorages using greased plastic sleeves and grease-filled end caps. Additionally, anchorage components are fully encapsulated in a high-density polyethylene plastic covering and an optional encapsulated intermediate coupler anchorage system can be used to protect the strand at construction joints.
Un-bonded post-tensioned concrete differs from bonded post-tensioning by providing each individual cable permanent freedom of movement relative to the concrete, to achieve this; each individual tendon is coated with grease (generally lithium-based) and covered by a plastic sheathing formed in an extrusion process.
The transfer of tension to the concrete is achieved by the steel cable acting against steel anchors in the perimeter of the slab.
The main disadvantage over bonded post-tensioning is the fact that a cable can de-stress itself and burst out of the slab if damaged (such as during repair on the slab).
