The Method of Prestressed Concrete is invented in the year 1928 for overcoming concrete’s natural weakness in tension. It can be used to produce bridges, flyovers building aqueduct, silo’s, chimneys, dams etc. etc. It can be accomplished in two ways.
Prestressing is a method of inducing known permanent stresses in a structure or member before the full or live load is applied. These stresses are induced by tensioning the High Tensile Strands, wires or rods, and then anchored to the member being Prestressed, by mechanical means.
JK Post Tensioning Anchorage system used to transfer the pre-stressing force to the concrete comprise of a Tube Unit, Bearing plate and conical shaped wedge. The Bearing plate is a medium carbon steel material having drilled holes with conical shape for holding the strand with the conical shaped three-piece wedges. The Bearing plate is also named as Anchor head. The Tube unit is a cast iron material placed at the ends, and is set into the concrete structure. The Tube Units allowed for strands spreading out for anchoring. A tapped hole is provided to the tube Unit for grout injection.
The Tube Unit is also named as Guide Cone. The wedges holding strands are in three segments with serration inside for holding the required meter of strands. The three segments are held together in wire circlips.Pre-Tensioning Anchorage system does not have a Tube Unit or a Bearing plate, dead barrels & wedges are used for holding the strands.