Which means that strain is proportional to distance from neutral axis. The beam resists externally applied M by an internal moment which can be thought of as the force in each fibre multiplied by the distance of that fibre from the beam s neutral axis. Then draw the BMD, obtain the maximum moment which each member needs to resist and take account of the compressive force in each column. This section is satisfactory. Although we could try to reduce slab thickness in other places, we would normally retain a constant thickness and change steel sizes - but only in a manner which did not make the floor unbuildable.
Minimum cost is far more important than minimum weight.
Aquaduct Design Calculate the bending moment on each beam, assuming each beam carries an equal proportion of the total load.