Question

Consider the following statements:
1. At a point of inflection, the embedment length
need not exceed the development length L${}_{\sigma }$

2. The condition that $L_{\sigma }(\frac{M_1}{V}+L_0)$ need not be checked for negative reinforcement.

At least one-third of the total negative
reinforcement provided must extend beyond
the point of inflection for a distance not less
than 'd' or 12$\varphi$ or clear-span whichever is
larger.

Which of these statements are correct?

• A. 1, 2 and 3
• B. 1 and 2
• C. 1 and 3
• D. 2 and 3

Answer 1

The correct option is B 1 and 2

(b)
The development length $L_d=\frac{\varphi {\sigma }_s}{4{\tau }_{bd}}$

$\varphi \to$ nominal diameter of the bar.

${\varphi }_s\to$ stress in bar at the section considered at design load.

${\tau }_{bd}\to$ design bond stress
At simple supports and at points of inflection positive moment tension reinforcement shall be limited to a diameter such that

$L_d\le \frac{M_1}{V}+L_o$

This condition need not to be checked for negative reinforcement.