Question $3(15$ marks$)$

$($a$)$ Select a suitable UB section to function as a simply supported beam in a

steel frame, carrying a $130mm$ thick solid concrete slab, together with a

variable imposed characteristic action of $5\mathrm{.}0k\frac{N}{m^2}.$ The beam span, $L,$ is $9m$

and the beams are spaced at $3\mathrm{.}5m$ intervals. The slab may be assumed to be

capable of providing continuous lateral restraint to the compression flange of

the beam.

Assume:

$45715267$UKB steel beam

Grade S$275$ steel

Take self$-$weight of the beam as $1k\frac{N}{m}$

Take the density of concrete $=2400k\frac{g}{m^3}$

A deflection limit of $\frac{L}{200}$

Due to the lateral restraint from the slab, there is no possibility of lateral torsional

buckling, so the beam should be checked for:

$($i$)$ Local buckling

$($ii$)($In$-$plane$)$ bending moment resistance

$($iii$)$ Shear resistance

$($iv$)$ Combined shear and bending

$($v$)$ Deflections

$(14$ marks$)$

$($b$)$ Draw a typical cross$-$section for the beam.

$(1$ mark$)$