Question

If the area of tensile steel reinforcement is doubled, the moment of resistance of the beam
increases only by about
​

Answer 1

If the area of tensile steel reinforcement is doubled, the moment of resistance of the beam increases only by about 22%.

Explanation:

If the area of tensile steel reinforcement is doubled, the moment of resistance of the beam increases only by about 22%.

Steel reinforcement bars or rebars are used to improve the concrete's tensile strength, as concrete is very low in tension but strong in compression. Only steel is used as rebar because its coefficient of thermal expansion or elongation due to high temperatures is almost equal to that of concrete.

If a beam bends under load, the length of the horizontal fiber varies. This is called the internal resistance moment.