Beams of Uniform Strength:

Generally, a beam has the similar cross-sectional area during the span. But the bending moment because of loads on the beam is not the similar at all of sections of the beam. For the maximum bending moment, we design the beam. Therefore, maximum permissible stress takes place in the extreme layers of the beam only at the specific section where the bending moment is maximum. At all of other sections, the stresses in the extreme layers of the beam are less than the permissible stress.

Since the bending moment decreases towards the supports, the cross-section of the beam might also be decreased towards the support. It ensures that the stress in the extreme layers attain permissible stress at each & every section of the beam. Such a beam is known as a beam of uniform strength.

The cross-section of any beam of consistent strength might be decreased by one of the following ways:

1. depth of beam is varied keeping the width constant.

2. width of beam is varied keeping the depth constant.

3. width & depth are both varied.

The following instance deals with a beam where the depth is varied keeping the width constant.