shear failure and stirrups

[RJcivileng]

hi
i have a question
for a concrete beam which was not designed in proper way for shear (shear deficiencies )
should the stirrups reach its ultimate yield strength ( fy) before the longitudinal steel?
or shear failure happens only when concrete becomes cracked very much

 

[asixth]

If the shear reinforcement is anchored around longitudinal reo and there is enough of them so that a crack has to cross them then a shear failure should be noticeable by a crack creating a differential level on the surface or soffit (possibly up to 1/8"). Hopefully it is noticed before an ultimate loading condition.