prestress concrete concept
Prestress concrete technology are used widely over the world. The capacity of reinforced concrete member is limited. Reinforced concrete under load it will crack and this will reduce durability of concrete structure due to ingress of water and harmful material to concrete. So prestressing is used to increase concrete member capacity by compressing concrete using high tensile cable. So the load has to cancel the compression from prestressing concrete before it could affect the concrete member.
If cables tensioned before casting concrete this called pretension but if the cables tensioned after casting concrete this is post-tensioning
This have many benefits such as increasing member strength , durability , span to depth ration and reducing section dimension.