Question

Consider the singly reinforced beam section given below (left figure). The stress block parameters for the cross-section from IS : 456-2000 are also given below (right figure). The moment of resistance for the given section by the limit method is _______kN-m.

• A. 42.7708

Answer 1

The correct option is A 42.7708
$A_{st}=4\times \frac{\pi }{4}\times {12}^2=452.38m{m}^2$

$x_{u^{\prime }max}=0.48\times 300$

= 144 mm

$\therefore C=T$

$\Rightarrow 0.36f_{ck}b{x}_u=0.87f_y{A}_{st}$

$\Rightarrow x_u=\frac{0.87f_y{A}_{st}}{0.36f_{ck}b}=90.73mm$

$\therefore x_u<x_{u,lim}$

it is under reinforced section

$\therefore MOR=0.36f_{ck}b{x}_u(d-0.42x_u)$
$=42.7708\times {10}^6$ N-mm
$=42.7708$ kN-m