Question

The percentage loss of pre-stress due to anchorage slip of 3 mm in a concrete beam of length 30 m, which is post-tensioned by a tendon with an initial stress of 1200 N/mm${}^2$ and modulus of elasticity equal to 2.1 x 10${}^5$N/mm${}^2$ is

• A. 0.0175
• B. 0.175
• C. 1.75
• D. 17.5

Answer 1

The correct option is C 1.75

Initial stress = 1200 N/mm${}^2$
loss in stress $=strainduetoslip\times modulusofelasticity$

$=\frac{3}{30000}\times 2.1\times {10}^5$

$=21N/m{m}^2$