Which of the following expressions is correct to calculate the limiting moment of resistance in accordance with the limit state design of a singly reinforced rectangular beam? Consider that the grade of steel is Fe500, fCK = characteristic compressive strength of concrete. b is the width of beam and d is the effective depth of beam.
1
Mu, lim = 0.1338 fck bd2
2
Mu, lim = 0.1498 fck bd2
3
Mu, lim = 0.1573 fck bd2
4
Mu, lim = 0.1389 fck bd2