Question

A cantilever beam of T cross-section carries uniformly distributed load. Where does the maximum magnitude of the bending stress occur?

• A. At the top of cross-section
• B. At the junction of flange and web
• C. At the mid-depth point
• D. At the bottom of the section

Answer 1

The correct option is D At the bottom of the section

The neutral axis shifts towards the flange of T-beam. Hence the bottom most fibre of web is more distant than the top most fibre of the flange from neutral axis. As we know that the bending stress is given by

$f=\frac{M}{I}y$

For a particular loading and beam cross section, M and I are constant.

$\therefore f\propto y$

Since y in case of bottom most fibre of T-beam is more, hence bending stress will be maximum here. It may noted that bottom most fibre of T-beam will be in compression and top most fibre will be in tension.