Understanding stresses and modular ratios

Singly reinforced Sections | Design of RCC Structures

In our series of articles for singly reinforced sections, 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 discussion on “assumptions for singly reinforced sections”.

1. The sections that are plane before bending remain plane after bending, at any cross-section.
2. All tensile stresses are taken up by steel reinforcement and none by concrete.
3. The stress to strain relationship of steel and concrete under working load is a straight line.
4. The modular ratio m has the value 280/3σcbc
5. There is a perfect adhesion between steel and concrete and no slip takes place between steel and concrete.