As per IS:$800-2007$, design of a cantilever steel beam section for its moment capacity requires fulfilment of an upper bound, expressed as:
\[
M_{d} \leq 1.5 Z_{e} \frac{f_{y}}{\gamma_{m 0}}
\]
The reason for such upper bound is to
- control deflection
- restrain lateral-torsional buckling
- avoid plastic deformation under working load
- avoid yielding at ultimate load
