Question

A simply supported beam of T-section is subjected to a uniformly distributed load acting vertically downwards. Its neutral axis is located at 25 mm from the top of the flange and the total depth of the section is 100 mm. The ratio of maximum tensile stress to maximum compressive stress in the beam is

• A. 2.0
• B. 2.5
• C. 3.0
• D. 4.0

Answer 1

The correct option is C 3.0

Let the maximum tensile stress and maximum compressive stress be $f_t$ and $f_c$ respectively. The distribution of stresses in the beam is shown below.

From the rule of similar triangles, we have

$\frac{f_t}{100-25}=\frac{f_c}{25}$

$\Rightarrow \frac{f_t}{f_c}=\frac{75}{25}=3$