Compression is borne entirely by concrete
Steel possesses initial stresses when embedded in concrete
Plane sections transverse to the centre line of the beam before bending remain plane after bending
Elastic moduli for concrete and steel have different values within the limits of deformation of the beam
Answer is Right!
Answer is Wrong!
The correct answer is: C. Plane sections transverse to the centre line of the beam before bending remain plane after bending.
This is known as the Bernoulli principle of beam bending. It states that, in the elastic range, plane sections before bending remain plane after bending. In other words, the cross-section of a beam does not change shape when it is bent. This principle is used to calculate the stresses and strains in a beam.
The other options are incorrect.
- Option A is incorrect because compression is not borne entirely by concrete. Steel also bears some of the compression.
- Option B is incorrect because steel does not possess initial stresses when embedded in concrete. The stresses in the steel are zero when the beam is first loaded.
- Option D is incorrect because the elastic moduli for concrete and steel are not the same. The elastic modulus of concrete is much lower than the elastic modulus of steel.