This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
Fig. 180 shows the bending of the bars for stirrups. The ends of the stirrups rest on the forms and support the beam bars, which assist in keeping these bars in place. The ends of the stirrups seldom show on the bottom of the slab of the finished floor. Sufficient mortar seems to get under the ends of the stirrups to cover them. Type a is much more extensively used than type b.
Fig. 180. Bending of Bars for Stirrups.
The latter type is generally used when a large amount of steel is required for stirrups, or if the stirrups are made of very small bars.