Question

A T-beam of flange width 1200 mm, flange thickness 100 mm, rib width 275 mm has an effective depth of 550 mm and is reinforced with 6 bars of 25 mm$\varphi$. The ultimate MOR will be ____ kNm. [Use M30 concrete and Fe415 steel]

• A. 400
• B. 800
• C. 548.21
• D. 100

Answer 1

The correct option is C 548.21

$A_{st}=6\times \frac{\pi }{4}(25{)}^2=2945.24m{m}^2$

$x_{u,lim}=0.48\times 550=264mm$

Assume neutral axis in flange.

$x_u=\frac{0.87\times 415\times 2945.24}{0.36\times 30\times 1200}=82.05mm<D_f(=100mm)$

$\therefore MOR=0.87f{A}_{st}(d-0.42x_u)$

$=0.87\times 415\times 2945.24\times (550-0.42\times 82.05)$

$=548.21\times {10}^6$N-mm = 548.21 kN-m