that the stringers (longitudinal reinforcement) are sufficiently
strong, the shear capacity of the beam will be exhausted in the following
way: at a certain load level the stirrups will reach the
yield stress (it is assumed that the beam is not overreinforced with
stirrups). Once the stirrups are yielding, increasing shear force can
only be carried by increasing the compression stress, which at the
same time rotates to smaller angles. The concrete stress may increase
until it reaches the effective compression strength and the beam