Which statement about shear reinforcement in reinforced concrete is most accurate?

• A. It resists shear forces and helps prevent diagonal cracking.
• B. It mainly increases bending stiffness.
• C. It resists axial loads.
• D. It has no significant effect.

Answer: (A)

Shear reinforcement is placed to carry shear forces and prevent diagonal cracking in reinforced concrete members. When a beam experiences shear, diagonal cracks tend to form and propagate; the transverse reinforcement (stirrups) crosses these cracks and provides resistance to the shear flow, turning part of the load into tensile forces in the stirrups and compressive resistance in the surrounding concrete. This action increases the shear capacity of the member and improves its ductility, helping to delay or avert brittle failure. It does not primarily increase bending stiffness—that role comes from the section’s geometry and the longitudinal reinforcement—and it is not meant to resist axial loads, which are carried mainly by the longitudinal steel and the cross-section itself. So, resisting shear forces and reducing diagonal cracking is the key function of shear reinforcement.