Determine from the first principles the maximum value of eccentricity $e,$ at which the

load $P_b($as defined in the clause $39\mathrm{.}7\mathrm{.}1\mathrm{.}1$ of IS $456)$ can be applied on the column section

shown in the following figure. Give your answer as a fraction of the total depth of the

section. The loss of concrete area due to compression steel is to be ignored. Consider

M$15$ concrete and Fe$415$ steel.