What is the net result of vertical and horizontal shear in a loaded beam or slab?

What is the net result of vertical and horizontal shear in a loaded beam or slab?

• A. Diagonal tension
• B. Diagonal compression
• C. Pure shear
• D. Buckling

Answer: (A)

When vertical and horizontal shear act together in a beam or slab, their forces combine to produce a resultant that acts along a diagonal across the cross-section. The stress on that diagonal plane is tensile, so the net effect is diagonal tension. This diagonal tensile stress causes the characteristic 45-degree shear cracks in concrete, which is exactly what shear reinforcement (stirrups) is designed to resist. Buckling is a separate instability under compression, and pure shear describes a different idealized state, not the actual diagonal tensile failure pattern observed in reinforced concrete shear. So the net result you’re looking for is diagonal tension.

When vertical and horizontal shear act together in a beam or slab, their forces combine to produce a resultant that acts along a diagonal across the cross-section. The stress on that diagonal plane is tensile, so the net effect is diagonal tension. This diagonal tensile stress causes the characteristic 45-degree shear cracks in concrete, which is exactly what shear reinforcement (stirrups) is designed to resist. Buckling is a separate instability under compression, and pure shear describes a different idealized state, not the actual diagonal tensile failure pattern observed in reinforced concrete shear. So the net result you’re looking for is diagonal tension.