Situation $19$: A $250300mm$ concrete beam is prestressed with a prestressing force of $530kN$ at an eccentricity of $60mm.$

The beam carries a superimposed load of $50k\frac{N}{m}.$

Calculate the stress at the top.

$1\mathrm{.}41$MPa

$1\mathrm{.}39$MPa

$1\mathrm{.}34$MPa

$1\mathrm{.}30$MPa

Calculate the stress at the bottom.

$15\mathrm{.}23$MPa

$15\mathrm{.}55$MPa

$15\mathrm{.}67$MPa

$15\mathrm{.}78$MPa

Calculate the maximum span that can be carried by the beam.

$4m$

$3m$

$6m$

$9m$