A rectangular reinforced concrete beam is $2500$x$2000$mm$($bxd$).$Determine the moment of resistance of the section,if fck$=25$N$/$mm$2,$fyk$=500$N$/$mm$2,$fyk link$=500$N$/$mm$2,$nominal concrete cover,cnom$=30$mm$,$weight of concrete$=25$N$/$mm$3,$characteristics of actions,finishes$=1\mathrm{.}0$kn$/$m$2,$variable qk$=1\mathrm{.}5$kn$/$m$2$ and diameter bar assumed bar $1=20$mm$,$bar $2=12$mm and bar link $=6$mm