Pre-Stressed Concrete:

The concrete in that internal stresses are intentionally induced in a systematic planned manner such that the stresses resulting from the superimposed loads get counter balanced to a desire degree is called a pre-stress concrete.

The principle of pre-stressing concrete consists of inducing sufficient compressive stress in concrete before a member is subjected to loads, in the zones which develop tensile stress due to applied load. A pre-induced compressive stress in concrete neutralizes the tensile stress developed due to external loads. Hence, zone ultimately will be free from any stress. Within a pre-stressed member, the whole cross-section becomes effective for resisting bending and danger of cracking is minimized.