Question

The development length of a deformed reinforcement bar can be expressed as (1/k) ($\varphi {\sigma }_s/{\tau }_{bd}$). From the IS : 456-2000, the value of k can be calculated as ______.

• A. 6.4

Answer 1

The correct option is A 6.4
$0.87f_y\frac{\pi }{4}{\varphi }^2=L_d{\tau }_{bd}\pi \varphi$

$L_d=\frac{0.7f_y\varphi }{4{\tau }_{bd}\times 1.6}$

$=\frac{{\sigma }_s\varphi }{6.4{\tau }_{bd}}$

(For deformed bar, increase ${\tau }_{bd}$ by 60%)