The cross$-$section of a multi$-$span rectangular beam which is subjected to a bending moment of $160kNm$ is shown in Figure $6\mathrm{.}45.$ Using the data given and assuming $15\%$ redistribution, determine the areas of main steel which are required.

Data:

Concrete strength class

Characteristic strength of steel $(f_{yk})$

Nominal maximum aggregate size $(h_{\text{a}\text{g}\text{g}})$

C$40/50$

Diameter of main tension steel

$500$MPa

Diameter of main compression steel

$20mm$

Diameter of shear links

Exposure class $($assume cement$/$combination type IIA in Table NA$\mathrm{.}2)$

Minimum required standard fire resistance

Intended working life

Assume that no quality system in accordance with Clause $4\mathrm{.}4\mathrm{.}1\mathrm{.}3(3)$ of EC $2$ exists.

EN $1992$: Design of Reinforced Concrete Elements

$227$

Solution:

UK NA to EN $1992-1-1$:$2004$

Minimum cover due to environmental conditions. BS $8500-1$:$2006$: Table A$.4$ for $50$ years

For exposure class XS$1$ and strength class C$40/50c_{\text{m}\text{i}\text{n}\text{,}\text{d}\text{u}\text{r}}=30mm$