Prestress Concrete - Unbonded Post-Tensioning
Prestressed concrete is a form of concrete used in construction that, while under construction, is substantially "prestressed" (compressed) in the areas that will be subjected to tensile forces while in service in order to strengthen it against these forces.[1][2]:3–5 [3] This compression is produced by the tensioning of high-strength "tendons" located within or adjacent to the concrete volume and is done to improve the performance of the concrete in service.[4] Tendons may consist of single wires, multi-wire strands or threaded bars that are most commonly made from high-tensile steels, carbon fiber or aramid fiber.[1]:52–59 The essence of prestressed concrete is that once the initial compression has been applied, the resulting material has the characteristics of high-strength concrete when subject to any subsequent compression forces and of ductile high-strength steel when subject to tension forces. This can result in improved structural capacity and/or serviceabi
