Shear strength of any material is the maximum shear load a body can withstand before failure occurs divided by its cross sectional area.

#### Shear strength of concrete is affected by following factors:

1.Tensile strength of concrete: The inclined cracking load in shear is
a function of the tensile strength of concrete.

2.Longitudinal reinforcement ratio: The shear strength of the RC beams is
found to drop significantly if the longitudinal reinforcement ratio is
decreased below 1.2–1.5 per cent.

3.Shear span to effective depth ratio: Its effect is pronounced when av /d is less than two and has no effect
when it is greater than six.

4.Lightweight aggregate concrete: They reduce tensile strength than
concrete with normal aggregates.

5.Size of beam: As the depth of the beam increases, the shear stress at failure
decreases.

6.Axial forces : Axial
tension decreases the inclined cracking load and the shear strength of
concrete, whereas axial compression does just the opposite.

7.Size of coarse aggregate: Increasing the size of coarse
aggregates increases the roughness of the crack surfaces, thus allowing higher
shear stresses to be transferred across the cracks.

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