Design of Singly Reinforced Beam

The procedure to be followed in designing of singly reinforced concrete beams to Eurocode 2 is discussed in the article. The basic steps to be followed are explained simply with relevant notes and remarks for ease of understanding.

Following steps could be followed in the order given

1. Considered x/d = 0.45; this value is considered in the EC2 for the designs
2. Calculated the Effective Depth (d) based on the cover, assumed link and bar diameters.
3. Calculate the K = M / ( b d² f_ck ); where the “M” is the applied bending moment, “b” is the width of the beam, “d” is the effective depth and “f_ck” is characteristic cylinder strength of the concrete.
4. Check K < K’ = 0.167. If this is satisfied, the beam can be designed as singly reinforced or otherwise it shall be designed as a double reinforcement section which will be discussed in a different article.
5. Find the lever arm; Z = d [ 0.5 + √ (0.25 – K / 1.134)]
6. Check Z < 0.95d, if satisfiy use the same or otherwise use Z = 0.95d
7. Find the As = M / (0.87 f_yk Z) , where f_yk is the charateristic strenght of the steel.
8. Check for minimum reinforcements; A_{s provided} > 0.26 (f_ctm / f_yk )bd but not less than 0.0013bd, where f_ctm is the mean value of axial tensile strength of concrete to be obtained from Table 3.1: Strength and deformation characteristics for concrete of Eurocode 2.
9. Check the Maximum reinforcements; (100 A_{s provided} /A_c) < 4

If the above procedures are followed strictly, a singly reinforced section can be designed as per the Eurocode 2