Reinforcement Detailing of Beams from ETABS output

Beam fails due to 

1)Shear failure

2)Flexural failure

SHEAR FAILURE:-

When the shear stress on an object exceeds the maximum permissible shear stress, then the object undergoes a failure .Shear failure can be defined as a failure that takes place due to insufficient of shear resistance.

Shear strength is the strength of a material or component against the type of yield or structural failure where the material or component fails in shear.

In simple words shear stress is maximum at 45 degree in cross section of beam hence diagonal crack is formed in shear failure and shear failure occurs at the end of the beam where beam connects to the column.To avoid this failure stirrups are provided.

Shear failure can be easily determined by checking out the excessive deflection or development of cracks, which gives an advance warning about the probable occuranceof shear failure.

The reason behind shear failure:-

1) It may occur due to insufficient knowledge of the resistance between reinforced steel rods and concrete column.

2) It may occur due to the wrong inter pretation of the data made available to the design engineer.

3) It may even take place due to mismatch in the positioning of the reinforcement steel rods.

Flexural Failure:-

It is also known as modulus of rupture, bond strength, or fracture strength, is a material property defined as the stress in a material just before it yields in a flexure test.

Flexure failure is of two type

1)Brittle failure

2)Ductile failure