Determine the required thickness for the retaining wall shown exposed to lateral earth pressure. Use f$\text{'}$c $=28$ Mpa $,$ fy $=415$Mpa. Use diamater $25$mm bars. Use clear cover of $50$mm and use As $=0\mathrm{.}5$Asmax. Use $1\mathrm{.}2$DL $+1\mathrm{.}6($Soil pressure for design$)$