Guide to design of Singly reinforced Sections | Civil Engineering
For “Singly reinforced sections” article series, we have covered the following:
- Basic definitions and formulas
- Understanding stresses and modular ratios
- Assumptions for singly reinforced sections
- Design procedure for Singly reinforced section – I
- Solved Numericals for Singly reinforced beam | Method I
- Design of Singly reinforced sections | Design Method 2
- Solved Numericals for Singly reinforced beam | Method 2
- Moment of Resistance for Singly reinforced sections
- Solved numerical example | Moment of resistance
- Solved numerical example 2 | Guide to singly reinforced sections
Now we will move on with our next solved example in which we will make use of formulas derived earlier. That is why it is necessary that you go through the entire step by step guide in order to gain complete understanding.
Numerical Problem
Calculate the moment of resistance of an RC beam 250mm wide, the depth of the centre of reinforcement being 500mm. Assume σcbc = 5N/mm2, σst = 140 N/mm2, modular ratio = 18.66
Given that,
b = width of the beam = 250mm
d = depth of the beam = 500mm
σcbc = permissible compressive stress in concrete in bending = 5N/mm2
σst = permissible stress in steel = 140 N/mm2
m = modular ratio = 18.66
To find Neutral Axis (NA)
σcbc /(σst/m) = xc/(d – xc)
5/(140/18.66) = xc/(500 – xc)
Xc = 199.95mm = 200mm