The modulus of elasticity of concrete is derived from the stress-strain curve by considering
- ASecant modulus at 0.2% strain
- BInitial tangent modulus at the origin
- CTangent modulus at the peak stress
- DSecant modulus at a specific stress levelCorrect
Solution
Concept
Secant modulus of concrete
Formula
Ec = 5000√fck
Step-by-step solution
1. Concrete is non-linear, so the modulus is taken as a secant modulus at a specified stress level (e.g. 0.33 fck).
Explanation
The secant modulus up to a specific stress level is used.
Why the other options are wrong
Initial tangent and peak tangent are not used in design.
Shortcut
Secant at a stress level.
Correct answer: D) Secant modulus at a specific stress level