Question

In case of pre-tensioned RC beams

• A. shrinkage of concrete is of the order of $3\times {10}^{-4}$
• B. relaxation of steel can be ignored
• C. only one wire can be stretched at a time
• D. even mild steel can be used for prestessing

Answer 1

The correct option is A shrinkage of concrete is of the order of $3\times {10}^{-4}$

As per IS 1343, the shrinkage of concrete is given to be $3\times {10}^{-4}$. Shrinkage of concrete in pre-stressed members results in shortening of tension wires and contributes to loss of prestress.