Torsion Equation Derivation for Reinforced Concrete (Step-by-Step Animation)

👋 Background

Torsion in reinforced concrete is commonly analysed using the thin-walled hollow section analogy. In this method, a solid rectangular section is considered into an equivalent thin-walled section, which the shear flow around the perimeter to be evaluated. This article presents a step-by-step derivation of the torsion equation.

🔍 Derivation of the Thin-Walled Torsion Equation

Although the derivation is applicable to thin-walled sections of any shape, a rectangular section is used here as the example because it is the most common case in practice.

The derivation follows these steps:

• Convert the solid rectangular section into an equivalent thin-walled hollow section.

• Understand the shear flow acting around the perimeter of the hollow section.

• Isolate a small element of the wall with consider of the force equilibrium equations.

🔍 Formula of the Thin-Walled Torsion Equation

Hope that now you can have better understanding about how this equation come from. For further calcualtions and guideline about torsion or even other reinforced section design, feel free to visit other part of civilsimple.

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