A symmetrical I$-$section beam supports an imposed load of $2\mathrm{.}5$ kN$/$m over a span of $8$ m$.$ The sectional details are: flange $-400$ mm wide and $80$ mm thick, web thickness $=100$ mm$,$ overall depth of the beam $=400$ mm$.$ At the centre of the span, the initial prestressing force of $125$ kN is located at $75$ mm from the soffit of the beam, loss ratio $\backslash$eta $=0\mathrm{.}8.$ Estimate the stresses at mid$-$span section of the beam for the load conditions: $($i$)$ Prestress $+$ Self Weight $($ii$)$ Prestress $+$ Self Weight $+$ Live load.