Question

A reinforced concrete beam is to be post-tensioned in such a way that no tensile stress develops at the time of post-tensioning. The distance of the tendon from the nearest face must be

• A. $\text{between}\frac{d}{5}\text{and}\frac{d}{4}$
  where $d$ is the depth of the beam
• B. $<\frac{d}{6}$
  where $d$ is the depth of the beam
• C. $\text{between}\frac{d}{4}\text{and}\frac{d}{3}$
  where $d$ is the depth of the beam
• D. $>\frac{d}{3}$
  where $d$ is the depth of the beam

Answer 1

The correct option is D $>\frac{d}{3}$

where $d$ is the depth of the beam
The eccentricity e should be less than d/6. The distance of tendons from the nearest face i.e. soffit of the beam is $(\frac{d}{2}-e)$


for $e\le \frac{d}{6}$ we have, $\frac{d}{2}-e>\frac{d}{3}$